Action Physics

Action Physics is an attribute of the dynamics of a physical system from which the equations of motion of the system can be derived. Action Physics is the Study of Motion. Stillness is an illusion. Everything is moving. If standing still on Earth you're moving 800 miles per second or 2,880,000 MPH. "All entities move and nothing remains still" - Heraclitus.

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Newton's balls or Executive Ball Clicker Action Theory the processes causing willful human bodily movements of a more or less complex kind.

Potential - Flight - Spin - Elastic - Physics

Reaction Physics all forces occur in pairs such that if one object exerts a force on another object, then the second object exerts an equal and opposite reaction force on the first. The third law is also more generally stated as: "To every action there is always opposed an equal reaction: or the mutual actions of two bodies upon each other are always equal, and directed to contrary parts." The attribution of which of the two forces is the action and which is the reaction is arbitrary. Either of the two can be considered the action, while the other is its associated reaction.

Principle of Least Action is a variational principle that, when applied to the action of a mechanical system, can be used to obtain the equations of Motion for that system. Principle of Least Effort - Water.

Action Formulas

The units of Action are Energy times Time, or ML2/T (Mass x Length x Length / Time).

Speed is the magnitude of its velocity (the rate of change of its position). Acceleration.

Velocity of an object is the rate of change of its position with respect to a frame of reference, and is a function of time.

Duration is the amount of elapsed time between two events. Rotation - Pendulum.

D = V x T  (Distance equals Velocity multiplied by Time)

Flight - Gravity - Pressure - Motion - E = mc²

Action has the Dimension of Energy x Time, where a Physical System follows simultaneously all possible paths with amplitudes determined by the action. For the action integral to be well defined the Trajectory has to be bounded in time and space. Spatial Intelligence - Time Management.


Force is any interaction that, when unopposed, will change the motion of an object. In other words, a force can cause an object with mass to change its velocity (which includes to begin moving from a state of rest), i.e., to accelerate. Force can also be described by intuitive concepts such as a push or a pull. A force has both magnitude and direction, making it a vector quantity. It is measured in the SI unit of newtons and represented by the symbol F. Isaac Newton.

F = ma (Force equals mass times acceleration). The net force on an object is equal to the mass of the object multiplied by the acceleration of the object.

Agency is the state of being in action or exerting power. How a result is obtained or an end is achieved. Control - Agency.

Restoring Force is a force that gives rise to an equilibrium in a physical system. If the system is perturbed away from the equilibrium, the restoring force will tend to bring the system back toward equilibrium. The restoring force is a function only of position of the mass or particle. It is always directed back toward the equilibrium position of the system. The restoring force is often to in simple harmonic motion. The force which is responsible to restore original size and shape is called restoring force. An example is the action of a spring. An idealized spring exerts a force that is proportional to the amount of deformation of the spring from its equilibrium length, exerted in a direction to oppose the deformation. Pulling the spring to a greater length causes it to exert a force that brings the spring back toward its equilibrium length. The amount of force can be determined by multiplying the spring constant of the spring by the amount of stretch. Another example is of a pendulum. When the pendulum is not swinging all the forces acting on the pendulum are in equilibrium. The force due to gravity and the mass of the object at the end of the pendulum is equal to the tension in the string holding that object up. When a pendulum is put in motion the place of equilibrium is at the bottom of the swing, the place where the pendulum rests. When the pendulum is at the top of its swing the force bringing the pendulum back down to this midpoint is gravity. As a result gravity can be seen as the restoring force in this. Restoring force of a spring : ( f=-kx ).

Conservative Force is a force with the property that the work done in moving a particle between two points is independent of the taken path. Equivalently, if a particle travels in a closed loop, the net work done (the sum of the force acting along the path multiplied by the displacement) by a conservative force is zero. A conservative force is dependent only on the position of the object. If a force is conservative, it is possible to assign a numerical value for the potential at any point. When an object moves from one location to another, the force changes the potential energy of the object by an amount that does not depend on the path taken. If the force is not conservative, then defining a scalar potential is not possible, because taking different paths would lead to conflicting potential differences between the start and end points. Gravitational Force is an example of a conservative force, while Frictional Force is an example of a non-conservative force. Other examples of conservative forces are: force in elastic spring, electrostatic force between two electric charges, magnetic force between two magnetic poles. The last two forces are called central forces as they act along the line joining the centres of two charged/magnetized bodies. Thus, all central forces are conservative forces.

Harmonic Oscillator is a system that, when displaced from its equilibrium position, experiences a restoring force, F, proportional to the displacement, x:

Centrifugal Force is used to refer to an inertial force directed away from the axis of rotation that appears to act on all objects when viewed in a Rotating reference frame. Centrifugal Force is an inertial force (also called a "fictitious" or "pseudo" force) that appears to act on all objects when viewed in a rotating frame of reference. It is directed away from an axis passing through the coordinate system's origin and parallel to the axis of rotation. If the axis of rotation passes through the coordinate system's origin, the centrifugal force is directed radially outwards from that axis. The concept of centrifugal force can be applied in rotating devices, such as centrifuges, centrifugal pumps, centrifugal governors, and centrifugal clutches, and in centrifugal railways, planetary orbits and banked curves, when they are analyzed in a rotating coordinate system. The term has sometimes also been used for the reactive centrifugal force that may be viewed as a reaction to a centripetal force in some circumstances.

Fans - Propellers - Spin

If two individual forces are of equal magnitude and opposite direction, then the forces are said to be balanced. An object is said to be acted upon by an unbalanced force only when there is an individual force that is not being balanced by a force of equal magnitude and in the opposite direction.

Magnetics - Reaction Force - E = mc²

Chain Fountain phenomenon, also known as the self-siphoning beads or the Mould effect, is a counterintuitive physical phenomenon observed with a chain of beads placed inside a jar, when one end of the chain is yanked from the jar and is allowed to fall to the floor beneath. This establishes a self-sustaining flow of the chain of beads which rises up from the jar into an arch ascending into the air over and above the edge of the jar with a noticeable gap, and down to the floor or ground beneath it, as if being sucked out of the jar by an invisible siphon.

Fictitious Force is an apparent force that acts on all masses whose motion is described using a non-inertial frame of reference, such as a rotating reference frame.

Electromotive Force is the voltage developed by any source of electrical energy such as a battery or dynamo. It is generally defined as the electrical potential for a source in a circuit.  A device that supplies electrical energy is called electromotive force or emf. Emfs convert chemical, mechanical, and other forms of energy into electrical energy. The product of such a device is also known as emf.

Coriolis Force is an inertial force (also called a fictitious force) that acts on objects that are in motion relative to a rotating reference frame. In a reference frame with clockwise rotation, the force acts to the left of the motion of the object. In one with anticlockwise rotation, the force acts to the right. Though recognized previously by others, the mathematical expression for the Coriolis force appeared in an 1835 paper by French scientist Gaspard-Gustave de Coriolis, in connection with the theory of water wheels. Early in the 20th century, the term Coriolis force began to be used in connection with meteorology. Deflection of an object due to the Coriolis force is called the 'Coriolis effect'. Ocean Currents.

Recoil is the backward movement of a gun when it is discharged. In technical terms, the recoil momentum acquired by the gun exactly balances the forward momentum of the projectile and exhaust gases (ejecta), according to Newton's third law, known as conservation of momentum. In hand-held small arms, the recoil momentum is transferred to the ground through the body of the shooter; while in heavier guns such as mounted machine guns or cannons, recoil momentum is transferred to the ground through the mount.

World's Heaviest Weight (youtube) By calibrating your Force Transducer on the world's biggest weight - 1,000,000 pounds of force. This machine ensures planes don't break apart, jets provide required thrust, and rockets make it to their destination. Futek.

Centripetal Force is a force that makes a body follow a curved path. Its direction is always orthogonal to the motion of the body and towards the fixed point of the instantaneous center of curvature of the path.

As your cornering speed increases, the force pushing you to the outside of the turn increases. These forces are absorbed by your car's suspension resulting in the body leaning to the outside of the corner. On the free upper part, there is centrifugal force which is caused by the inertia of the free upper part of your body tending to continue in a straight line as the car makes a turn to the right. Thus, the upper part of your body tends to lean left as the car turns right. Chariot Racing (wiki).

Bicycle and Motorcycle Dynamics is the science of the motion of bicycles and motorcycles and their components, due to the forces acting on them. Dynamics falls under a branch of physics known as classical mechanics. Bike motions of interest include balancing, steering, braking, accelerating, suspension activation, and vibration. The study of these motions began in the late 19th century and continues today. Bicycles and motorcycles are both single-track vehicles and so their motions have many fundamental attributes in common and are fundamentally different from and more difficult to study than other wheeled vehicles such as dicycles, tricycles, and quadracycles. As with unicycles, bikes lack lateral stability when stationary, and under most circumstances can only remain upright when moving forward. Experimentation and mathematical analysis have shown that a bike stays upright when it is steered to keep its center of mass over its wheels. This steering is usually supplied by a rider, or in certain circumstances, by the bike itself. Several factors, including geometry, mass distribution, and gyroscopic effect all contribute in varying degrees to this self-stability, but long-standing hypotheses and claims that any single effect, such as gyroscopic or trail, is solely responsible for the stabilizing force have been discredited. While remaining upright may be the primary goal of beginning riders, a bike must lean in order to maintain balance in a turn: the higher the speed or smaller the turn radius, the more lean is required. This balances the roll torque about the wheel contact patches generated by centrifugal force due to the turn with that of the gravitational force. This lean is usually produced by a momentary steering in the opposite direction, called countersteering. Countersteering skill is usually acquired by motor learning and executed via procedural memory rather than by conscious thought. Unlike other wheeled vehicles, the primary control input on bikes is steering torque, not position. Although longitudinally stable when stationary, bikes often have a high enough center of mass and a short enough wheelbase to lift a wheel off the ground under sufficient acceleration or deceleration. When braking, depending on the location of the combined center of mass of the bike and rider with respect to the point where the front wheel contacts the ground, bikes can either skid the front wheel or flip the bike and rider over the front wheel. A similar situation is possible while accelerating, but with respect to the rear wheel.

A cyclist must lean into a turn to prevent tipping over in the other direction. The frictional force provides the centripetal force necessary to turn the cyclist to the left. But the frictional force also produces a clockwise torque that will cause the rider and bicycle to tip clockwise to the right. When a car or truck makes a turn it cannot lean into the turn. The torque that prevents it from tipping away from the turn arises from the normal force on the outside tires being larger than the normal force on the inside tires.

Countersteering is used by single-track vehicle operators, such as cyclists and motorcyclists, to initiate a turn toward a given direction by momentarily steering counter to the desired direction ("steer left to turn right"). To negotiate a turn successfully, the combined center of mass of the rider and the single-track vehicle must first be leaned in the direction of the turn, and steering briefly in the opposite direction causes that lean. The rider's action of countersteering is sometimes referred to as "giving a steering command". The scientific literature does not provide a clear and comprehensive definition of countersteering. In fact, "a proper distinction between steer torque and steer angle is not always made. Center of Mass.


Pressure is the force applied perpendicular to the surface of an object per unit area over which that force is distributed.

pressure force area F = Force applied by the body.
A = Total area of the object.

Where, h is the height, ρ is density, g is gravity. Pressure Formula is used to calculate pressure, force, area, density, height and gravity if some of these quantities are given. Pressure is expressed in Pascal (Pa).

Boyle's Law is an experimental gas law that describes how the pressure of a gas tends to increase as the volume of the container decreases. A modern statement of Boyle's law is the absolute pressure exerted by a given mass of an ideal gas is inversely proportional to the volume it occupies if the temperature and amount of gas remain unchanged within a closed system. The pressure law states that for a constant volume of gas in a sealed container the temperature of the gas is directly proportional to its pressure. This can be easily understood by visualizing the particles of gas in the container moving with a greater energy when the temperature is increased.

Wind Pressure - Wing Pressure - Barometric Pressure (High Pressure / Low Pressure)

Compressor - Breathing - Vacuum - Negative Pressures (wiki) - Positive Pressure Room

Partial Pressure. In a mixture of gases, each constituent gas has a partial pressure which is the notional pressure of that constituent gas if it alone occupied the entire volume of the original mixture at the same temperature. The total pressure of an ideal gas mixture is the sum of the partial pressures of the gases in the mixture. The partial pressure of a gas is a measure of thermodynamic activity of the gas's molecules. Gases dissolve, diffuse, and react according to their partial pressures, and not according to their concentrations in gas mixtures or liquids. This general property of gases is also true in chemical reactions of gases in biology. For example, the necessary amount of oxygen for human respiration, and the amount that is toxic, is set by the partial pressure of oxygen alone. This is true across a very wide range of different concentrations of oxygen present in various inhaled breathing gases or dissolved in blood. The partial pressures of oxygen and carbon dioxide are important parameters in tests of arterial blood gases, but can also be measured in, for example, cerebrospinal fluid.

Pressure Sensor is a device for pressure measurement of gases or liquids. Pressure is an expression of the force required to stop a fluid from expanding, and is usually stated in terms of force per unit area. A pressure sensor usually acts as a transducer; it generates a signal as a function of the pressure imposed, such a signal is electrical. Pressure sensors are used for control and monitoring in thousands of everyday applications. Pressure sensors can also be used to indirectly measure other variables such as fluid/gas flow, speed, water level, and altitude. Pressure sensors can alternatively be called pressure transducers, pressure transmitters, pressure senders, pressure indicators, piezometers and manometers, among other names. Body Senses Pressure.

Pressure Measurement is the analysis of an applied force by a fluid (liquid or gas) on a surface. Pressure is typically measured in units of force per unit of surface area. Many techniques have been developed for the measurement of pressure and vacuum. Instruments used to measure and display pressure in an integral unit are called pressure gauges or vacuum gauges. A manometer is a good example as it uses a column of liquid to both measure and indicate pressure. Likewise the widely used Bourdon gauge is a mechanical device which both measures and indicates and is probably the best known type of gauge.- Pressure Gage is an instrument indicating pressure.

Pascal unit is the SI derived unit of pressure used to quantify internal pressure, stress, Young's modulus and ultimate tensile strength. It is defined as one newton per square metre. Common multiple units of the pascal are the hectopascal (1 hPa = 100 Pa) which is equal to one millibar, and the kilopascal (1 kPa = 1000 Pa) which is equal to one centibar. The unit of measurement called standard atmosphere (atm) is defined as 101325 Pa. Meteorological reports typically state atmospheric pressure in millibars. (symbol: Pa).

Pressure Cooking is the process of cooking food, using water or other cooking liquid, in a sealed vessel known as a pressure cooker. This simulates the effects of long braising within a shorter time. Almost any food that can be cooked in steam or water-based liquids can be cooked in a pressure cooker. The cooker works by trapping the steam produced from boiling the cooking liquid inside the vessel. This causes internal pressure and temperature to rise quickly. After use, the steam is slowly released so that the vessel can be opened safely.


Gyroscope Precession Momentum is the product of the mass and velocity of an object.

Moment of Inertia determines the torque needed for a desired angular acceleration about a rotational axis.

Angular Momentum is the rotational analog of linear momentum, which is a vector quantity defined as the product of an object's mass, m, and its velocity, v. Linear momentum is denoted by the letter p and is called “momentum” for short. Linear momentum is defined as the product of a system's mass multiplied by its velocity. What IS Angular Momentum?? (youtube).

Conservation of Angular Momentum in a closed system, no torque can be exerted on any matter without the exertion on some other matter of an equal and opposite torque. Hence, angular momentum can be exchanged between objects in a closed system, but total angular momentum before and after an exchange remains constant (is conserved). Seen another way, a rotational analogue of Newton's first law of motion might be written, "A rigid body continues in a state of uniform rotation unless acted by an external influence." Thus with no external influence to act upon it, the original angular momentum of the system remains constant. The law of conservation of angular momentum states that when no external torque acts on an object, no change of angular momentum will occur.

Inertia is the resistance of any physical object to any change in its state of motion (this includes changes to its speed, direction or state of rest). Inertia is also defined as the tendency of objects to keep moving in a straight line at a constant velocity. A property of matter by which it continues in its existing state of rest or uniform motion in a straight line, unless that state is changed by an external force. There is no measurable difference between gravitational mass and inertial mass.

List of Moments of Inertia is the mass moment of inertia, usually denoted by I, measures the extent to which an object resists rotational acceleration about a particular axis, and is the rotational analogue to mass. Mass moments of inertia have units of dimension ML2([mass] × [length]2). It should not be confused with the second moment of area, which is used in bending calculations. The mass moment of inertia is often also known as the rotational inertia, and sometimes as the angular mass. Quantized Inertia is a fringe theory of inertia. (Unruh radiation and horizon mechanics). Negative Mass.

Inertial Frame of Reference in classical physics and special relativity is a frame of reference in which a body with zero net force acting upon it is not accelerating; that is, such a body is at rest or it is moving at a constant speed in a straight line. In analytical terms, it is a frame of reference that describes time and space homogeneously, isotropically, and in a time-independent manner. Conceptually, the physics of a system in an inertial frame have no causes external to the system. An inertial frame of reference may also be called an inertial reference frame, inertial frame, Galilean reference frame, or inertial space.

Non-Inertial Reference Frame is a frame of reference that is undergoing acceleration with respect to an inertial frame. An accelerometer at rest in a non-inertial frame will in general detect a non-zero acceleration. In a curved spacetime all frames are non-inertial. The laws of motion in non-inertial frames do not take the simple form they do in inertial frames, and the laws vary from frame to frame depending on the acceleration. To explain the motion of bodies entirely within the viewpoint of non-inertial reference frames, fictitious forces (also called inertial forces, pseudo-forces and d'Alembert forces) must be introduced to account for the observed motion, such as the Coriolis force or the centrifugal force, as derived from the acceleration of the non-inertial frame. As stated by Goodman and Warner, "One might say that F = ma holds in any coordinate system provided the term 'force' is redefined to include the so-called 'reversed effective forces' or 'inertia forces'.

Correspondence Rules govern the principle of replacing physical quantities with operators. Such replacements include energy and momentum, which can be derived informally from taking the time and space derivities of the plane wave function. These show a similarity to the Heisenberg Uncertainty Principle, which is any of a variety of mathematical inequalities asserting a fundamental limit to the precision with which certain pairs of physical properties of a particle, known as complementary variables, such as position x and momentum p, can be known.


Gimbal Gimbal is a pivoted support that allows the rotation of an object about a single axis. A set of three gimbals, one mounted on the other with orthogonal pivot axes, may be used to allow an object mounted on the innermost gimbal to remain independent of the rotation of its support (e.g. vertical in the first animation). For example, on a ship: the gyroscopes, shipboard compasses, stoves, and even drink holders typically use gimbals to keep them upright with respect to the horizon despite the ship's pitching and rolling. The Space Travel Machine in the 1997 Movie named Contact, was a film adaptation of Carl Sagan's 1985 novel.

Gyroscope is a spinning wheel or disc in which the axis of rotation is free to assume any orientation by itself. When rotating, the orientation of this axis is unaffected by tilting or rotation of the mounting, according to the conservation of angular momentum. Because of this, gyroscopes are useful for measuring or maintaining orientation. The main reason gyroscopes seem to defy gravity is the effective torque applied to the spinning disc has on its angular momentum vector. The influence of gravity on the plane of the spinning disc causes the rotational axis to "deflect". Gyroscopic Primer by Prof Eric Laithwaite Full Video (youtube) - Anti Gravity Wheel.

Gyroscopic Effect is ability of the rotating body to maintain a steady direction of its axis of rotation. The gyroscopes are rotating with respect to the axis of symmetry at high speed.

Perpetual Motion - Anti-Gravity - Generator - Kinetic Energy

The world's smallest optical gyroscope, Spinning the light. Engineers create an optical gyroscope smaller than a grain of rice. The new gyroscope from Hajimiri's lab achieves this improved performance by using a new technique called "reciprocal sensitivity enhancement." In this case, "reciprocal" means that it affects both beams of the light inside the gyroscope in the same way. Since the Sagnac Effect relies on detecting a difference between the two beams as they travel in opposite directions, it is considered nonreciprocal. Inside the gyroscope, light travels through miniaturized optical waveguides (small conduits that carry light, that perform the same function as wires do for electricity). Imperfections in the optical path that might affect the beams (for example, thermal fluctuations or light scattering) and any outside interference will affect both beams similarly. Hajimiri's team found a way to weed out this reciprocal noise while leaving signals from the Sagnac effect intact. Reciprocal sensitivity enhancement thus improves the signal-to-noise ratio in the system and enables the integration of the optical gyro onto a chip smaller than a grain of rice.

Caster Angle is the angular displacement of the steering axis from the vertical axis of a steered wheel in a car, motorcycle, bicycle or other vehicle, measured in the longitudinal direction.

Precession is a change in the orientation of the rotational axis of a rotating body. In an appropriate reference frame it can be defined as a change in the first Euler angle, whereas the third Euler angle defines the rotation itself. In other words, if the axis of rotation of a body is itself rotating about a second axis, that body is said to be precessing about the second axis. A motion in which the second Euler angle changes is called nutation. In physics, there are two types of precession: torque-free and torque-induced. In astronomy, precession refers to any of several slow changes in an astronomical body's rotational or orbital parameters. An important example is the steady change in the orientation of the axis of rotation of the Earth, known as the precession of the equinoxes. Earth is fatter or bigger at the equator because of spin.

Magnus Effect is the commonly observed effect in which a spinning ball (or cylinder) curves away from its principal flight path.


Spinning is to revolve quickly and repeatedly around one's own axis. Head Spin (dizzy).

Spin in physics is an intrinsic form of angular momentum carried by elementary particles, composite particles (hadrons), and atomic nuclei. Centrifugal Force.

Spin-1/2 an intrinsic property of all elementary particles. All known fermions, the particles that constitute ordinary matter, have a spin of 1/2. The spin number describes how many symmetrical facets a particle has in one full rotation; a spin of 1/2 means that the particle must be fully rotated twice (through 720°) before it has the same configuration as when it started. Particles having net spin 1/2 include the proton, neutron, electron, neutrino, and quarks. The dynamics of spin-1/2 objects cannot be accurately described using classical physics; they are among the simplest systems which require quantum mechanics to describe them. As such, the study of the behavior of spin-1/2 systems forms a central part of quantum mechanics.

Spinor are elements of a complex vector space that can be associated with Euclidean space. Like geometric vectors and more general tensors, spinors transform linearly when the Euclidean space is subjected to a slight (infinitesimal) rotation. However, when a sequence of such small rotations is composed (integrated) to form an overall final rotation, the resulting spinor transformation depends on which sequence of small rotations was used: unlike vectors and tensors, a spinor transforms to its negative when the space is continuously rotated through a complete turn from 0° to 360°. This property characterizes spinors: spinors can be viewed as the "square roots" of vectors.

Proton Spinning is the reason why Everything Spins. (above and below). Pulsars can Spin as fast as Atoms.

Spintronics also known as spin electronics, is the study of the intrinsic spin of the electron and its associated magnetic moment, in addition to its fundamental electronic charge, in solid-state devices.

Molecular Spintronics. Chemists and physicists have designed, deposited and operated single molecular spin switches on surfaces. The newly developed molecules feature stable spin states and do not lose their functionality upon adsorption on surfaces. Practical spin wave transistor one step closer.

Spin Wave are propagating disturbances in the ordering of magnetic materials. These low-lying collective excitations occur in magnetic lattices with continuous symmetry. From the equivalent quasiparticle point of view, spin waves are known as magnons, which are boson modes of the spin lattice that correspond roughly to the phonon excitations of the nuclear lattice. As temperature is increased, the thermal excitation of spin waves reduces a ferromagnet's spontaneous magnetization. The energies of spin waves are typically only μeV in keeping with typical Curie points at room temperature and below. The discussion of spin waves in antiferromagnets is beyond the scope of this article.

A new energy-efficient mechanism using the Rashba effect. Scientists have proposed new quasi-1D materials for potential spintronic applications, an upcoming technology that exploits the spin of electrons. They performed simulations to demonstrate the spin properties of these materials and explained the mechanisms behind their behavior. Conventional electronics is based on the movement of electrons and mainly concerns their electric charge; unfortunately, we are close to reaching the physical limits for improving electronic devices. However, electrons bear another intrinsic quantum-physical property called "spin," which can be interpreted as a type of angular momentum and can be either "up" or "down." While conventional electronic devices do not deploy the spin of the electrons that they employ, spintronics is a field of study in which the spin of the conducting electrons is crucial. Serious improvements in performance and new applications can be attained through "spin currents."

GHz Rotation of an Optically Trapped Nanoparticle in Vacuum. Rotating an optically trapped silica nanoparticle in vacuum by transferring spin angular momentum of light to the particle's mechanical angular momentum. At sufficiently low damping, realized at pressures below 10−5 mbar, we observe rotation frequencies of single 100 nm particles exceeding 1 GHz. We find that the steady-state rotation frequency scales linearly with the optical trapping power and inversely with pressure, consistent with theoretical considerations based on conservation of angular momentum. Rapidly changing the polarization of the trapping light allows us to extract the pressure-dependent response time of the particle's rotational degree of freedom.

Gyrobus is an electric bus that uses flywheel energy storage, not overhead wires like a trolleybus. The name comes from the Greek language term for flywheel, gyros. While there are no gyrobuses currently in use commercially, development in this area continues.

Flywheel is a mechanical device specifically designed to efficiently store rotational energy (kinetic energy). Flywheels resist changes in rotational speed by their moment of inertia. The amount of energy stored in a flywheel is proportional to the square of its rotational speed and its mass. The way to change a flywheel's stored energy without changing its mass is by increasing or decreasing its rotational speed. Since flywheels act as mechanical energy storage devices, they are the kinetic-energy-storage analogue to electrical capacitors, for example, which are a type of accumulator. Like other types of accumulators, flywheels smooth the ripple in power output, providing surges of high power output as required, absorbing surges of high power input (system-generated power) as required, and in this way act as low-pass filters on the mechanical velocity (angular, or otherwise) of the system. Common uses of a flywheel include: Smoothing the power output of an energy source. For example, flywheels are used in reciprocating engines because the active torque from the individual pistons is intermittent. Energy storage systems. Delivering energy at rates beyond the ability of an energy source. This is achieved by collecting energy in a flywheel over time and then releasing it quickly, at rates that exceed the abilities of the energy source. Controlling the orientation of a mechanical system, gyroscope and reaction wheel. Flywheels are typically made of steel and rotate on conventional bearings; these are generally limited to a maximum revolution rate of a few thousand RPM. High energy density flywheels can be made of carbon fiber composites and employ magnetic bearings, enabling them to revolve at speeds up to 60,000 RPM (1 kHz). Carbon-composite flywheel batteries have recently been manufactured and are proving to be viable in real-world tests on mainstream cars. Additionally, their disposal is more eco-friendly than traditional lithium ion batteries.

Flywheel Energy Storage works by accelerating a rotor (flywheel) to a very high speed and maintaining the energy in the system as rotational energy. When energy is extracted from the system, the flywheel's rotational speed is reduced as a consequence of the principle of conservation of energy; adding energy to the system correspondingly results in an increase in the speed of the flywheel. Most FES systems use electricity to accelerate and decelerate the flywheel, but devices that directly use mechanical energy are being developed. Advanced FES systems have rotors made of high strength carbon-fiber composites, suspended by magnetic bearings, and spinning at speeds from 20,000 to over 50,000 rpm in a vacuum enclosure. Such flywheels can come up to speed in a matter of minutes – reaching their energy capacity much more quickly than some other forms of storage. Batteries (mechanical battery).

Rotational Energy or angular kinetic energy is kinetic energy due to the rotation of an object and is part of its total kinetic energy. Looking at rotational energy separately around an object's axis of rotation, the following dependence on the object's moment of inertia is observed.

Planck Constant is a physical constant that is the quantum of action, central in quantum mechanics.


Rotation is a circular movement of an object around a center or point of rotation. A three-dimensional object always rotates around an imaginary line called a rotation axis. If the axis passes through the body's center of mass, the body is said to rotate upon itself, or spin.

is the center around which something rotates. Centrifuge - Orbit.

Rotation Around a Fixed Axis is a special case of rotational motion. The fixed axis hypothesis excludes the possibility of an axis changing its orientation, and cannot describe such phenomena as wobbling or precession. According to Euler's rotation theorem, simultaneous rotation along a number of stationary axes at the same time is impossible. If two rotations are forced at the same time, a new axis of rotation will appear. This article assumes that the rotation is also stable, such that no torque is required to keep it going. The kinematics and dynamics of rotation around a fixed axis of a rigid body are mathematically much simpler than those for free rotation of a rigid body; they are entirely analogous to those of linear motion along a single fixed direction, which is not true for free rotation of a rigid body. The expressions for the kinetic energy of the object, and for the forces on the parts of the object, are also simpler for rotation around a fixed axis, than for general rotational motion. For these reasons, rotation around a fixed axis is typically taught in introductory physics courses after students have mastered linear motion; the full generality of rotational motion is not usually taught in introductory physics classes.

Tennis Racket Theorem is a result in classical mechanics describing the movement of a rigid body with three distinct principal moments of inertia. It is also dubbed the Dzhanibekov effect, The theorem describes the following effect: rotation of an object around its first and third principal axes is stable, while rotation around its second principal axis (or intermediate axis) is not. The experiment can be performed with any object that has three different moments of inertia. The effect occurs whenever the axis of rotation differs only slightly from the object's second principal axis; air resistance or gravity are not necessary.

The Bizarre Behavior of Rotating Bodies, Explained (youtube) - Magnetic Flip - Aircraft Principal Axes.

Nutation is a rocking, wobbling, swaying, or nodding motion in the axis of rotation of a largely axially symmetric object, such as a gyroscope, planet, or bullet in flight, or as an intended behavior of a mechanism. In an appropriate reference frame it can be defined as a change in the second Euler angle. If it is not caused by forces external to the body, it is called free nutation or Euler nutation. A pure nutation is a movement of a rotational axis such that the first Euler angle is constant. In spacecraft dynamics, precession (a change in the first Euler angle) is sometimes referred to as nutation.


Trajectory is the path that a moving object follows through space as a function of time. The object might be a projectile or a satellite.

Trajectory of a Projectile is the path that a thrown or launched projectile or missile without propulsion will take under the action of gravity, neglecting all other forces, such as friction from aerodynamic drag.


Torque is the tendency of a force to rotate an object about an axis.

Torsion in mechanics is the twisting of an object due to an applied torque. Torsion is expressed in newton per squared meter (Pa) or pound per squared inch (psi) while torque is expressed in newton metres (N·m) or foot-pound force (ft·lbf). In sections perpendicular to the torque axis, the resultant shear stress in this section is perpendicular to the radius.

Torsion Spring (twisting force) - Mousetrap (wiki) - Spring (elastic rubber)

Torsion Tensor is a manner of characterizing a twist or screw of a moving frame around a curve. The torsion of a curve, as it appears in the Frenet–Serret formulas, for instance, quantifies the twist of a curve about its tangent vector as the curve evolves (or rather the rotation of the Frenet–Serret frame about the tangent vector). In the geometry of surfaces, the geodesic torsion describes how a surface twists about a curve on the surface. The companion notion of curvature measures how moving frames "roll" along a curve "without twisting. Cheetah (image).

Vorticity is a pseudovector field that describes the local spinning motion of a continuum near some point (the tendency of something to rotate ), as would be seen by an observer located at that point and traveling along with the flow.

Capillary Action (water) - Erosion

Torsion Spring is a spring that works by twisting its end along its axis; that is, a flexible elastic object that stores mechanical energy when it is twisted. When it is twisted, it exerts a torque in the opposite direction, proportional to the amount (angle) it is twisted. There are various types: A torsion bar is a straight bar of metal or rubber that is subjected to twisting (shear stress) about its axis by torque applied at its ends. A more delicate form used in sensitive instruments, called a torsion fiber consists of a fiber of silk, glass, or quartz under tension, that is twisted about its axis. A helical torsion spring, is a metal rod or wire in the shape of a helix (coil) that is subjected to twisting about the axis of the coil by sideways forces (bending moments) applied to its ends, twisting the coil tighter. Clocks use a spiral wound torsion spring (a form of helical torsion spring where the coils are around each other instead of piled up) sometimes called a "clock spring" or colloquially called a mainspring. Those types of torsion springs are also used for attic stairs, clutches, and other devices that need near constant torque for large angles or even multiple revolutions.


Mach's Principle local inertial frames are determined by the large scale distribution of matter, as exemplified by this anecdote: You are standing in a field looking at the stars. Your arms are resting freely at your side, and you see that the distant stars are not moving. Now start spinning. The stars are whirling around you and your arms are pulled away from your body. Why should your arms be pulled away when the stars are whirling? Why should they be dangling freely when the stars don't move? Mach's principle says that this is not a coincidence—that there is a physical law that relates the motion of the distant stars to the local inertial frame. If you see all the stars whirling around you, Mach suggests that there is some physical law which would make it so you would feel a centrifugal force. There are a number of rival formulations of the principle. It is often stated in vague ways, like "mass out there influences inertia here". A very general statement of Mach's principle is "Local physical laws are determined by the large-scale structure of the universe.

Ernst Mach was an Austrian physicist and philosopher, noted for his contributions to physics such as study of shock waves. (18 February 1838 – 19 February 1916).

Ultrarelativistic Limit is when its speed is very close to the speed of light c. Light - Sound - Engineering.


Acceleration is the rate of change of velocity of an object with respect to time. An object's acceleration is the net result of any and all forces acting on the object, as described by Newton's Second Law. The SI unit for acceleration is metre per second squared (m s−2). Accelerations are vector quantities (they have magnitude and direction) and add according to the parallelogram law. As a vector, the calculated net force is equal to the product of the object's mass (a scalar quantity) and its acceleration. Accelerate is to cause something to move faster. Rockets.

Accelerometer is a device that measures proper acceleration. Proper acceleration, being the acceleration (or rate of change of velocity) of a body in its own instantaneous rest frame, is not the same as coordinate acceleration, being the acceleration in a fixed coordinate system. For example, an accelerometer at rest on the surface of the Earth will measure an acceleration due to Earth's gravity, straight upwards (by definition) of g ≈ 9.81 m/s2. By contrast, accelerometers in free fall (falling toward the center of the Earth at a rate of about 9.81 m/s2) will measure zero.

Velocity of an object is the rate of change of its position with respect to a frame of reference, and is a function of time. Velocity is equivalent to a specification of its speed and direction of motion (e.g. 60 km/h to the north).

Speed of an object is the magnitude of its velocity (the rate of change of its position); it is thus a scalar quantity. The average speed of an object in an interval of time is the distance travelled by the object divided by the duration of the interval; the instantaneous speed is the limit of the average speed as the duration of the time interval approaches zero. Speed has the dimensions of distance divided by time. The SI unit of speed is the metre per second, but the most common unit of speed in everyday usage is the kilometre per hour or, in the US and the UK, miles per hour. For air and marine travel the knot is commonly used. The fastest possible speed at which energy or information can travel, according to special relativity, is the speed of light in a vacuum c = 299,792,458 metres per second (approximately 1,079,000,000 km/h or 671,000,000 mph). Matter cannot quite reach the speed of light, as this would require an infinite amount of energy. In relativity physics, the concept of rapidity replaces the classical idea of speed.

Thrust is when a system expels or accelerates mass in one direction, the accelerated mass will cause a force of equal magnitude but opposite direction on that system. Propulsion.

Cheetahs can attain short bursts of speed well over 100 km/h (62 mph), the American quarter horse has topped 88 km/h (55 mph), greyhounds can reach 70 km/h (43 mph), and the Mongolian wild ass has been measured at 64 km/h (40 mph). Even the domestic cat may reach 48 km/h (30 mph). Human Running Speed.

Terminal Velocity is the highest velocity attainable by an object as it falls through a fluid (air is the most common example, but the concept applies equally to any fluid).

Angular Velocity of an object is the rate of change of its angular displacement with respect to time. The SI unit of angular velocity is radians per second. Angular velocity is usually represented by the symbol omega (ω, rarely Ω). When the angular velocity is represented as a vector, its direction is perpendicular to the plane of rotation, with its orientation conventionally specified by the right-hand rule.

Hypersonic Speed is one that is highly supersonic. Since the 1970s, the term has generally referred to speeds of Mach 5 and above. The precise Mach number at which a craft can be said to be flying at hypersonic speed varies, since individual physical changes in the airflow (like molecular dissociation and ionization) occur at different speeds; these effects collectively become important around Mach 5. The hypersonic regime is often alternatively defined as speeds where ramjets do not produce net thrust. Rocket Engines.

Speed of Sound is the distance travelled per unit time by a sound wave as it propagates through an elastic medium. In dry air at 0 °C (32 °F), the speed of sound is 331.2 metres per second (1,087 ft/s; 1,192 km/h; 741 mph; 644 kn). At 20 °C (68 °F), the speed of sound is 343 metres per second (1,125 ft/s; 1,235 km/h; 767 mph; 667 kn), or a kilometre in 2.91 s or a mile in 4.69 s.

Kinematics describes the motion of points (alternatively "particles"), bodies (objects), and systems of bodies without consideration of the masses of those objects nor the forces that may have caused the motion.

Fermi Acceleration is the acceleration that charged particles undergo when being repeatedly reflected, usually by a magnetic mirror (see also Centrifugal mechanism of acceleration). This is thought to be the primary mechanism by which particles gain non thermal energies in astrophysical shock waves. It plays a very important role in many astrophysical models, mainly of shocks including solar flares and supernova remnants.

Cosmic Rays - Atoms - Physics Math Information

The Quantum of action in the photon is not separated into a separate piece of time and a separate piece of energy. Each ordinary (observable) Photon in the universe consists of a little piece (quantum) of non-observable action. Light.


Gravity Pendulum Pendulum is a weight suspended from a pivot so that it can swing freely. When a pendulum is displaced sideways from its resting, equilibrium position, it is subject to a restoring force due to gravity that will accelerate it back toward the equilibrium position. When released, the restoring force combined with the pendulum's mass causes it to oscillate about the equilibrium position, swinging back and forth. The time for one complete cycle, a left swing and a right swing, is called the period. The period depends on the length of the pendulum and also to a slight degree on the amplitude, the width of the pendulum's swing.

How To Make A Pendulum Wave (Science Experiment / Physics Toy) (youtube)

Pendulum Clock is a clock that uses a pendulum, a swinging weight, as its timekeeping element. The advantage of a pendulum for timekeeping is that it is a harmonic oscillator: it swings back and forth in a precise time interval dependent on its length, and resists swinging at other rates.

Metronome (tempo) - Synchronicity - Principle Vibration

Harmonic Oscillator is a system that, when displaced from its equilibrium position, experiences a restoring force F proportional to the displacement x.

Spring Pendulum is a physical system where a piece of mass is connected to a spring so that the resulting motion contains elements of a simple pendulum as well as a spring. The system is much more complex than a simple pendulum, as the properties of the spring add an extra dimension of freedom to the system. For example, when the spring compresses, the shorter radius causes the spring to move faster due to the conservation of angular momentum. It is also possible that the spring has a range that is overtaken by the motion of the pendulum, making it practically neutral to the motion of the pendulum.

Agent is a substance that exerts some force or effect. An active and efficient cause; capable of producing a certain effect.

Wilberforce Pendulum consists of a mass suspended by a long helical spring and free to turn on its vertical axis, twisting the spring. It is an example of a coupled mechanical oscillator, often used as a demonstration in physics education. The mass can both bob up and down on the spring, and rotate back and forth about its vertical axis with torsional vibrations. When correctly adjusted and set in motion, it exhibits a curious motion in which periods of purely rotational oscillation gradually alternate with periods of purely up and down oscillation. The energy stored in the device shifts slowly back and forth between the translational 'up and down' oscillation mode and the torsional 'clockwise and counterclockwise' oscillation mode, until the motion eventually dies away. Despite the name, in normal operation it does not swing back and forth as ordinary pendulums do. The mass usually has opposing pairs of radial 'arms' sticking out horizontally, threaded with small weights that can be screwed in or out to adjust the moment of inertia to 'tune' the torsional vibration period. Coupled Oscillations is where energy alternates between two forms of oscillation.


Newton First Law Motion is a change in position of an object with respect to time. Motion is typically described in terms of displacement, distance, velocity, acceleration, time and speed. Motion of a body is observed by attaching a frame of reference to an observer and measuring the change in position of the body relative to that frame. Gravity - Chaotic Motion.

Newton's 3 Laws of Motion (wiki)

First Law:
If a body is at rest it remains at rest or, if it is in motion, it moves with uniform velocity, until it is acted on by a resultant force.

Second Law: The resultant force is equal to mass times acceleration. A resultant force, also called a net force, is a force equal to the sum of all forces applied to an object. Materials Science.

Third Law: For every action, there is an equal and opposite reaction. Or every action always reacts in the opposite direction.

Philosophiae Naturalis Principia Mathematica is a work in three books by Isaac Newton, in Latin, first published 5 July 1687. After annotating and correcting his personal copy of the first edition, Newton published two further editions, in 1713 and 1726. The Principia states Newton's laws of motion, forming the foundation of classical mechanics; Newton's law of universal gravitation; and a derivation of Kepler's laws of planetary motion (which Kepler first obtained empirically). The Principia is considered as one of the most important works in the history of science.

Introduction to Motion (youtube)

Equations of Motion are equations that describe the behaviour of a physical system in terms of its motion as a function of time. More specifically, the equations of motion describe the behaviour of a physical system as a set of mathematical functions in terms of dynamic variables: normally spatial coordinates and time are used, but others are also possible, such as momentum components and time. The most general choice are generalized coordinates which can be any convenient variables characteristic of the physical system. The functions are defined in a Euclidean space in classical mechanics, but are replaced by curved spaces in relativity. If the dynamics of a system is known, the equations are the solutions to the differential equations describing the motion of the dynamics.

Locomotion is the power or the ability to move or to have self-propelled movement.

Move is to change location and to travel or to proceed to some place or to a new position.

Reaction states that all forces occur in pairs such that if one object exerts a force on another object, then the second object exerts an equal and opposite reaction force on the first. The third law is also more generally stated as: "To every action there is always opposed an equal reaction: or the mutual actions of two bodies upon each other are always equal, and directed to contrary parts." The attribution of which of the two forces is the action and which is the reaction is arbitrary. Either of the two can be considered the action, while the other is its associated reaction.

Body Motion (Human Body)

7 Myths About Movement (youtube)

Displacement as a vector is a vector that is the shortest distance from the initial to the final position of a point P. It quantifies both the distance and direction of an imaginary motion along a straight line from the initial position to the final position of the point. A displacement may be also described as a 'relative position': the final position of a point (Sf) relative to its initial position (Si), and a displacement vector can be mathematically defined as the difference between the final and initial position vectors.

Mechanics is an area of science concerned with the behaviour of physical bodies when subjected to forces or displacements, and the subsequent effects of the bodies on their environment. Mechanics is the branch of physics concerned with the motion of bodies in a frame of reference. The technical aspects of doing something.

Quantum Mechanics

Dynamics in mechanics is a branch of applied mathematics (specifically classical mechanics) concerned with the study of forces and torques and their effect on motion, as opposed to kinematics, which studies the motion of objects without reference to its causes. Isaac Newton defined the fundamental physical laws which govern dynamics in physics, especially his second law of motion. Materials Science.

Dynamics is the branch of mechanics concerned with the forces that cause motions of bodies.

Vehicular Dynamics refers to the dynamics of vehicles, here assumed to be ground vehicles. Vehicle dynamics is a part of engineering primarily based on classical mechanics.

Ricochet is to spring back or spring away from an impact.

Rebound is a movement back from an impact.

Bounce is to move up and down repeatedly.

Deflection is to turn away from a straight course, or fixed direction, or line of interest. Turn aside and away from an initial or intended course.

Locomotion is the power or the ability to move. Self-propelled movement.

Space Travel (rockets)

Work and Energy Formula

Work in relation to physics is when acting there is a displacement of the point of application in the direction of the force. For example, when a ball is held above the ground and then dropped, the work done on the ball as it falls is equal to the weight of the ball (a force) multiplied by the distance to the ground (a displacement).

Power in relation to physics is the rate of doing work."

Work in relation to electrical is the work done on a charged particle by an electric field. The equation for 'electrical' work is equivalent to that of 'mechanical' work. Energy - Machines


Potentiality and actuality is a change or activity that represents the possibility of something happening. The inherent capacity for coming into being. A possibility becomes real when knowledge of the requirements that are needed to complete a task are available. Not to say something will happen, it's saying that something could happen under the right conditions or requirements.

Potential is possessing numerous possibilities. The capacity for coming into being. Having prospect and the possibility of future success. Having capability and aptitude that may be developed. Having the skills and qualifications to do things well.

Action-Specific Perception is when people perceive their environment and events within it in terms of their ability to act.

Self-Fulfillment is the realizing of one's deepest desires and capacities. A satisfying and worthwhile life well lived.

Evoked Potential is an electrical potential recorded from the nervous system of a human or other animal following presentation of a stimulus, as distinct from spontaneous potentials as detected by electroencephalography (EEG), electromyography (EMG), or other electrophysiologic recording method. Such potentials are useful for electrodiagnosis and monitoring. Speed Reading.

Long-Term Potentiation is a persistent strengthening of synapses based on recent patterns of activity. These are patterns of synaptic activity that produce a long-lasting increase in signal transmission between two neurons. The opposite of LTP is long-term depression, which produces a long-lasting decrease in synaptic strength. It is one of several phenomena underlying synaptic plasticity, the ability of chemical synapses to change their strength. As memories are thought to be encoded by modification of synaptic strength, LTP is widely considered one of the major cellular mechanisms that underlies learning and memory.

Depotentiation is when the long term potentiation has been erased. The action of a substance that reduces the effect of another substance. Deficiencies.

Action Potential is a short-lasting event in which the electrical membrane potential of a cell rapidly rises and falls, following a consistent trajectory.

Resting Potential of quiescent cells is called the resting membrane potential or resting voltage, as opposed to the specific dynamic electrochemical phenomena called action potential and graded membrane potential. Apart from the latter two, which occur in excitable cells (neurons, muscles, and some secretory cells in glands), membrane voltage in the majority of non-excitable cells can also undergo changes in response to environmental or intracellular stimuli. The resting potential exists due to the differences in membrane permeabilities for potassium, sodium, calcium, and chloride ions, which in turn result from functional activity of various ion channels, ion transporters, and exchangers. Conventionally, resting membrane potential can be defined as a relatively stable, ground value of transmembrane voltage in animal and plant cells. The typical resting membrane potential of a cell arises from the separation of potassium ions from intracellular, relatively immobile anions across the membrane of the cell. Because the membrane permeability for potassium is much higher than that for other ions, and because of the strong chemical gradient for potassium, potassium ions flow from the cytosol into the extracellular space carrying out positive charge, until their movement is balanced by build-up of negative charge on the inner surface of the membrane. Again, because of the high relative permeability for potassium, the resulting membrane potential is almost always close to the potassium reversal potential. But in order for this process to occur, a concentration gradient of potassium ions must first be set up. This work is done by the ion pumps/transporters and/or exchangers and generally is powered by ATP. In the case of the resting membrane potential across an animal cell's plasma membrane, potassium (and sodium) gradients are established by the Na+/K+-ATPase (sodium-potassium pump) which transports 2 potassium ions inside and 3 sodium ions outside at the cost of 1 ATP molecule. In other cases, for example, a membrane potential may be established by acidification of the inside of a membranous compartment (such as the proton pump that generates membrane potential across synaptic vesicle membranes).

Membrane Potential is the difference in electric potential between the interior and the exterior of a biological cell. With respect to the exterior of the cell, typical values of membrane potential range from –40 mV to –80 mV. Porous.

Electric Potential is the amount of electric potential energy that a unitary point electric charge would have if located at any point in space, and is equal to the work done by an external agent in carrying a unit of positive charge from the arbitrarily chosen reference point (usually infinity) to that point without any acceleration. Natures Electrical Properties.

Electric Potential Energy is a potential energy (measured in joules) that results from conservative Coulomb forces and is associated with the configuration of a particular set of point charges within a defined system.

Potential Energy is energy possessed by a body by virtue of its position relative to others, stresses within itself, electric charge, and other factors. Batteries - Electric Potential Difference (voltage).

Yukawa Potential is the amplitude of potential, m is the mass of the particle, r is the radial distance to the particle, and k is another scaling constant, so that 1/km is the range. The potential is monotone increasing in r and it is negative, implying the force is attractive. In the SI system, the unit of the Yukawa potential is (1/m).

Multipotentiality is an educational and psychological term referring to the ability and preference of a person, particularly one of strong intellectual or artistic curiosity, to excel in two or more different fields. It can also refer to an individual whose interests span multiple fields or areas, rather than being strong in just one. Such traits are called multipotentialities, while "multipotentialites" has been suggested as a name for those with this trait. By contrast, those whose interests lie mostly within a single field are called "specialists."

Potential Well is the region surrounding a local minimum of potential energy. Energy captured in a potential well is unable to convert to another type of energy (kinetic energy in the case of a gravitational potential well) because it is captured in the local minimum of a potential well. Therefore, a body may not proceed to the global minimum of potential energy, as it would naturally tend to due to entropy.

Threshold Potential is the critical level to which a membrane potential must be depolarized to initiate an action potential. Threshold potentials are necessary to regulate and propagate signaling in both the central nervous system (CNS) and the peripheral nervous system (PNS). Thermodynamics.

Untapped is something that has not yet been fully utilized or used or taken advantage of. Information Potential.

Unlocking Potential is to free or release oneself from restraints, restrictions or doubts.

Opportunity is a favorable combination of circumstances that makes it possible to do something advantageous or beneficial for a particular purpose. A chance for making progress and achieving a goal.

Window of Opportunity is a period of time during which some action can be taken that will achieve a desired outcome. Once this period is over, or the "window is closed", the specified outcome is no longer possible. Launch Window.

Opportunity Cost is the cost that is incurred by not utilizing a benefit from an option that was chosen from alternatives.

Elastics - Bouncing Back

Elasticity in physics is the ability of a body to resist a distorting influence or deforming force and to return to its original size and shape when that influence or force is removed. Solid objects will deform when adequate forces are applied on them. If the material is Elastic, the object will return to its initial shape and size when these forces are removed. The physical reasons for elastic behavior can be quite different for different materials. In metals, the atomic lattice changes size and shape when forces are applied (energy is added to the system). When forces are removed, the lattice goes back to the original lower energy state. For rubbers and other polymers, elasticity is caused by the stretching of polymer chains when forces are applied.

Elastic is something capable of resuming original shape after stretching or compression; Springy. Able to adjust readily to different conditions.

Resilience - Adaptable - Surface Tension.

Silicone Rubber is an elastomer (rubber-like material) composed of silicone—itself a polymer—containing silicon together with carbon, hydrogen, and oxygen.

Rubber Band is a loop of Rubber, usually ring shaped, and commonly used to hold multiple objects together. The rubber band was patented in England on March 17, 1845, by Stephen Perry. Most rubber bands are manufactured out of natural rubber or, especially at larger sizes, elastomer, and are sold in a variety of sizes. Kinetic Energy.

Visco-Elastic Material absorbs, isolates, and reduces vibrations simultaneously. It is capable of absorbing nearly 95% of shock energy and reducing more than 50% of vibration energy. Sorbothane performs well in nearly every industrial application. Rubber hardens over time. Natural rubber degrades and hardens as heat, oils, and even simple oxygen cause chemical reactions. Therefore, limiting exposure to heat, oils, and oxygen is one way to delay the hardening of rubber objects. At the same time, however, properly employed heat or oil can restore some softness to rubber objects, although it is a battle that will eventually be lost. Placing rubber items in zip-close bags and using a straw to suck out most of the air can noticeably delay the hardening process. Heat the rubber with a blow dryer may help, but there are many rubber formulations, and some may respond better than others. Also, there is no miracle cure, and some hardened rubber items will simply be too far gone for softening. You are actually damaging the rubber by heating it to soften it, and some items cannot take the beating any longer.

Viscoelasticity is the property of materials that exhibit both viscous and elastic characteristics when undergoing deformation. Viscous materials, like water, resist shear flow and strain linearly with time when a stress is applied. Elastic materials strain when stretched and immediately return to their original state once the stress is removed. Viscoelastic materials have elements of both of these properties and, as such, exhibit time-dependent strain. Whereas elasticity is usually the result of bond stretching along crystallographic planes in an ordered solid, viscosity is the result of the diffusion of atoms or molecules inside an amorphous material.

Inelastic Collision is a collision in which kinetic energy is not conserved due to the action of internal friction. In collisions of macroscopic bodies, some kinetic energy is turned into vibrational energy of the atoms, causing a heating effect, and the bodies are deformed.

Elastic Collision is an encounter between two bodies in which the total kinetic energy of the two bodies remains the same. In an ideal, perfectly elastic collision, there is no net conversion of kinetic energy into other forms such as heat, noise, or potential energy.

Rubber Dampers or shock absorbers are used to reduce the transmission of shock to the surrounding structure. Shock absorption is possible as the rubber absorber deflects under the applied shock load. The construction of rubber dampers (also known as rectangular buffers) is such that rubber is bonded to a metal plate which incorporates a number of fixing holes allowing for simple installation. A wide range of dimensions and rubber hardness options are available from stock or alternatively rectangular buffers and rubber dampers can be specially manufactured to meet the customer's individual requirement. Slowmo Comparison between 2 gimbals on simple shake table Left: Newer stiffer rubber dampers (youtube).

Shock Absorber is a mechanical or hydraulic device designed to absorb and damp shock impulses. It does this by converting the kinetic energy of the shock into another form of energy (typically heat) which is then dissipated. Most shock absorbers are a form of dashpot (a damper which resists motion via viscous friction).

Vibration Isolation is the process of isolating an object, such as a piece of equipment, from the source of vibrations.

Vibration is a mechanical phenomenon whereby oscillations occur about an equilibrium point. The word comes from Latin vibrationem ("shaking, brandishing"). The oscillations may be periodic, such as the motion of a pendulum—or random, such as the movement of a tire on a gravel road. The studies of sound and vibration are closely related. Sound, or pressure waves, are generated by vibrating structures (e.g. vocal cords); these pressure waves can also induce the vibration of structures (e.g. ear drum). Hence, attempts to reduce noise are often related to issues of vibration.

Ball Joint are spherical bearings that connect the control arms to the steering knuckles. They are used on virtually every automobile made and work similarly to the ball-and-socket design of the human hip joint or Synovial Joint, which joins bones with a fibrous joint capsule that is continuous with the periosteum of the joined bones, constitutes the outer boundary of a synovial cavity, and surrounds the bones' articulating surfaces. The synovial cavity/joint is filled with synovial fluid. The joint capsule is made up of an outer layer, the articular capsule, which keeps the bones together structurally, and an inner layer, the synovial membrane, which seals in the synovial fluid. They are the most common and most movable type of joint in the body of a mammal. As with most other joints, synovial joints achieve movement at the point of contact of the articulating bones. (lso known as diarthrosis).

Resilin is an elastomeric protein found in many insects and arthropods. It provides soft rubber-elasticity to mechanically active organs and tissue; for example, it enables insects of many species to jump or pivot their wings efficiently. Resilin was first discovered by Torkel Weis-Fogh in locust wing-hinges. Resilin is currently the most efficient elastic protein known (Elvin et al., 2005). The elastic efficiency of the resilin isolated from locust tendon has been reported to be 97% (only 3% of stored energy is lost as heat). It does not have any regular structure but its randomly coiled chains are crosslinked by di- and tri-tyrosine links at the right spacing to confer the elasticity needed to propel some jumping insects distances up to 38 times their length (as found in fleas). Resilin must last for the lifetime of adult insects and must therefore operate for hundreds of millions of extensions and contractions; its elastic efficiency ensures performance during the insect's lifetime. Resilin exhibits unusual elastomeric behavior only when swollen in polar solvents such as water.

Fleas can jump 38 times their body length (jump speed is one thousandth of a second). Frogs can jump 20 times their body length. Jumping Spiders can jump 100 times their body length. At the 1968 Summer Olympics Bob Beamon jumped 8.90 m (29 ft 2 1⁄4 in) at an altitude of 7,349 feet (2,240 m), a jump not exceeded for 23 years, and which remains the second longest legal jump of all time.

Jump is to push oneself off a surface and into the air by using the muscles in the legs and feet. Gravity.

Elastomer is a polymer with viscoelasticity (i. e., both viscosity and elasticity) and very weak inter-molecular forces, and generally low Young's modulus and high failure strain compared with other materials. The term, a portmanteau of elastic polymer, is often used interchangeably with rubber, although the latter is preferred when referring to vulcanisates. Each of the monomers which link to form the polymer is usually a compound of several elements among carbon, hydrogen, oxygen and silicon. Elastomers are amorphous polymers maintained above their glass transition temperature, so that considerable molecular reconformation, without breaking of covalent bonds, is feasible. At ambient temperatures, such rubbers are thus relatively soft (E ≈ 3 MPa) and deformable. Their primary uses are for seals, adhesives and molded flexible parts. Application areas for different types of rubber are manifold and cover segments as diverse as tires, soles for shoes, and damping and insulating elements. The importance of these rubbers can be judged from the fact that global revenues are forecast to rise to US$56 billion in 2020. IUPAC defines the term "elastomer" by "Polymer that displays rubber-like elasticity." Rubber-like solids with elastic properties are called elastomers. Polymer chains are held together in these materials by relatively weak intermolecular bonds, which permit the polymers to stretch in response to macroscopic stresses. Natural rubber, neoprene rubber, buna-s and buna-n are all examples of such elastomers.

Catapult is a device in which accumulated tension is suddenly released to hurl an object some distance, in particular.

Spring as a device is an elastic object that stores mechanical energy. Springs are typically made of spring steel. There are many spring designs. In everyday use, the term often refers to coil springs. When a conventional spring, without stiffness variability features, is compressed or stretched from its resting position, it exerts an opposing force approximately proportional to its change in length (this approximation breaks down for larger deflections). The rate or spring constant of a spring is the change in the force it exerts, divided by the change in deflection of the spring. That is, it is the gradient of the force versus deflection curve. An extension or compression spring's rate is expressed in units of force divided by distance, for example lbf/in or N/m. A torsion spring is a spring that works by twisting; when it is twisted about its axis by an angle, it produces a torque proportional to the angle. A torsion spring's rate is in units of torque divided by angle, such as N·m/rad or ft·lbf/degree. The inverse of spring rate is compliance, that is: if a spring has a rate of 10 N/mm, it has a compliance of 0.1 mm/N. The stiffness (or rate) of springs in parallel is additive, as is the compliance of springs in series. Springs are made from a variety of elastic materials, the most common being spring steel. Small springs can be wound from pre-hardened stock, while larger ones are made from annealed steel and hardened after fabrication. Some non-ferrous metals are also used including phosphor bronze and titanium for parts requiring corrosion resistance and beryllium copper for springs carrying electrical current (because of its low electrical resistance).

Coil Spring is a mechanical device which is typically used to store energy and subsequently release it, to absorb shock, or to maintain a force between contacting surfaces. They are made of an elastic material formed into the shape of a helix which returns to its natural length when unloaded. Under tension or compression, the material (wire) of a coil spring undergoes torsion. The spring characteristics therefore depend on the shear modulus, not Young's Modulus. A coil spring may also be used as a torsion spring: in this case the spring as a whole is subjected to torsion about its helical axis. The material of the spring is thereby subjected to a bending moment, either reducing or increasing the helical radius. In this mode, it is the Young's Modulus of the material that determines the spring characteristics. Metal coil springs are made by winding a wire around a shaped former - a cylinder is used to form cylindrical coil springs.

Slinky is a precompressed helical spring toy invented by Richard James in the early 1940s. It can perform a number of tricks, including travelling down a flight of steps end-over-end as it stretches and re-forms itself with the aid of gravity and its own momentum, or appear to levitate for a period of time after it has been dropped. In the state of equilibrium of a slinky, all net force is cancelled throughout the entire slinky. This results in a stationary slinky with zero velocity. As the positions of each part of the slinky is governed by the slinky's mass, the force of gravity and the spring constant, various other properties of the slinky may be induced. Amazing Slinky Tricks (youtube).

Simple Harmonic Motion is a special type of periodic motion or oscillation where the restoring force is directly proportional to the displacement and acts in the direction opposite to that of displacement.

Somersaulting simulation for jumping bots. New simulation methods enable easier, faster design of elastic materials for robots and other dynamic objects.

Conservative Force is a force with the property that the work done in moving a particle between two points is independent of the taken path. Equivalently, if a particle travels in a closed loop, the net work done (the sum of the force acting along the path multiplied by the distance travelled) by a conservative force is zero.

Coulomb's Law is a law of physics that describes force interacting between static electrically charged particles.

Kinetic - Thermoelectric

Physics of Tennis (PDF)

Dancing T-Handle in Zero-G, HD, free floating rotation showing a bi-stable state due to intermediate moments of inertia (youtube)

How to imitate natural spring-loaded snapping movement without losing energy. Venus flytraps do it, trap-jaw ants do it, and now materials scientists can do it, too - they discovered a way of efficiently converting elastic energy in a spring to kinetic energy for high-acceleration, extreme velocity movements as nature does it.

Flight - Science of Flying

Thrust to Weight RatioFlight is the process by which an object moves through an atmosphere or through the air surrounding earth, or beyond the atmosphere into outer space such as spaceflight, without direct support from any surface. This can be achieved by generating aerodynamic lift, propulsive thrust, aerostatically using buoyancy, or by ballistic movement.

Aviation refers to the activities surrounding mechanical flight and the aircraft industry. Aircraft includes fixed-wing and rotary-wing types, morphable wings, wing-less lifting bodies, as well as lighter-than-air craft such as balloons and airships.

Aeronautics is the theory and practice of navigation through air or space. Aeronautics is the science or art involved with the study, design, and manufacturing of air flight–capable machines, and the techniques of operating aircraft and rockets within the atmosphere. The British Royal Aeronautical Society identifies the aspects of "aeronautical art, science and engineering" and "the profession of Aeronautics (which expression includes Astronautics).

Air Travel is a form of travel in vehicles such as helicopters, hot air balloons, blimps, gliders, hang gliding, parachuting, airplanes, jets, or anything else that can sustain flight. Use of air travel has greatly increased in recent decades – worldwide it doubled between the mid-1980s and the year 2000. Transportation.

Propulsion is the action or process of pushing or pulling to drive an object forward. A propulsion system consists of a source of mechanical power, and a propulsor (means of converting this power into propulsive force). A technological system uses an engine or motor as the power source (commonly called a powerplant), and wheels and axles, propellers, or a propulsive nozzle to generate the force. Components such as clutches or gearboxes may be needed to connect the motor to axles, wheels, or propellers. propulsion system is a machine that produces thrust to push an object forward. First, the thrust from the propulsion system must balance the drag of the airplane when the airplane is cruising. And second, the thrust from the propulsion system must exceed the drag of the airplane for the airplane to accelerate. Jet Propulsion (rockets).

Propeller is a type of fan that transmits power by converting rotational motion into thrust. A pressure difference is produced between the forward and rear surfaces of the airfoil-shaped blade, and a fluid (such as air or water) is accelerated behind the blade. Propeller dynamics, like those of aircraft wings, can be modelled by Bernoulli's principle and Newton's third law. Most marine propellers are screw propellers with fixed helical blades rotating around a horizontal (or nearly horizontal) axis or propeller shaft. Fans.

Aerodynamics is a branch of fluid dynamics concerned with studying the motion of air, particularly when it interacts with a solid object, such as an airplane wing. Aerodynamics is a sub-field of fluid dynamics and gas dynamics, and many aspects of aerodynamics theory are common to these fields. The term aerodynamics is often used synonymously with gas dynamics, with the difference being that "gas dynamics" applies to the study of the motion of all gases, not limited to air. Fluid Mechanics.

Bernoulli's Principle states that an increase in the speed of a fluid occurs simultaneously with a decrease in pressure or a decrease in the fluid's potential energy. If the air flowing past the top surface of an aircraft wing is moving faster than the air flowing past the bottom surface, then Bernoulli's principle implies that the pressure on the surfaces of the wing will be lower above than below. This pressure difference results in an upwards lifting force.

Wing is a type of fin that produces lift, while moving through air or some other fluid. As such, wings have streamlined cross-sections that are subject to aerodynamic forces and act as airfoils. A wing's aerodynamic efficiency is expressed as its lift-to-drag ratio. The lift a wing generates at a given speed and angle of attack can be one to two orders of magnitude greater than the total drag on the wing. A high lift-to-drag ratio requires a significantly smaller thrust to propel the wings through the air at sufficient lift. Lifting structures used in water, include various foils, such as hydrofoils. Hydrodynamics is the governing science, rather than aerodynamics. Applications of underwater foils occur in hydroplanes, sailboats and submarines. Air moves more quickly over the curved upper surface of the wing than it does under the wing, which has a flatter surface. The faster moving air produces less pressure than the slower moving air, causing the wing to lift toward the area of low pressure, thus creating lift. If you turned a wing upside down it would have the opposite effect and push down, like with racecar airfoils. An automotive wing is a device whose intended design is to generate downforce as air passes around it, not simply disrupt existing airflow patterns. As such, rather than decreasing drag, automotive wings actually increase drag. Spoiler is an automotive aerodynamic device whose intended design function is to 'spoil' unfavorable air movement across a body of a vehicle in motion, usually described as turbulence or drag. Spoilers on the front of a vehicle are often called air dams. Spoilers are often fitted to race and high-performance sports cars, Vortex Shedding - Pressure Changes.

Fixed-Wing Aircraft is a flying machine, such as an airplane (or aeroplane; see spelling differences), which is capable of flight using wings that generate lift caused by the aircraft's forward airspeed and the shape of the wings. Fixed-wing aircraft are distinct from rotary-wing aircraft (in which the wings form a rotor mounted on a spinning shaft or "mast"), and ornithopters (in which the wings flap in a manner similar to that of a bird). The wings of a fixed-wing aircraft are not necessarily rigid; kites, hang gliders, variable-sweep wing aircraft and airplanes that use wing morphing are all examples of fixed-wing aircraft. Gliding fixed-wing aircraft, including free-flying gliders of various kinds and tethered kites, can use moving air to gain altitude. Powered fixed-wing aircraft (airplanes) that gain forward thrust from an engine include powered paragliders, powered hang gliders and some ground effect vehicles. Most fixed-wing aircraft are flown by a pilot on board the craft, but some are specifically designed to be unmanned and controlled either remotely or autonomously (using onboard computers).

Airplane is a powered, fixed-wing aircraft that is propelled forward by thrust from a jet engine or propeller. Airplanes come in a variety of sizes, shapes, and wing configurations. Supply Chain.

How Planes Work - The Science Behind Airplanes

HOW AIRPLANES FLY - The Science Behind Flight (youtube)

Jet Aircraft is an aircraft or fixed-wing aircraft that is propelled by jet engines or jet propulsion.

Rockets (space travel)

Dynamics of Flight - Principles of Flight

Dynamics of Space Flight - NASA - Flight Dynamics (spacecraft)

Flight Envelope of an aircraft refers to the capabilities of a design in terms of airspeed and load factor or altitude.

Archer's Paradox refers to the phenomenon of an arrow traveling in the direction it is pointed at full draw, when it seems that the arrow would have to pass through the starting position it was in before being drawn, where it was pointed to the side of the target.

Aircraft Pilot or Aviator is a person who controls the flight of an aircraft by operating its directional flight controls. Some other aircrew members, such as navigators or flight engineers, are also considered aviators, because they are involved in operating the aircraft's navigation and engine systems. Other aircrew members, such as drone operators, flight attendants, mechanics and ground crew, are not classified as aviators.

Aircraft Flight Control System consists of flight control surfaces, the respective cockpit controls, connecting linkages, and the necessary operating mechanisms to control an aircraft's direction in flight. Aircraft engine controls are also considered as flight controls as they change speed. The fundamentals of aircraft controls are explained in flight dynamics. Bridge (ship controls).

Flight Instruments are the instruments in the cockpit of an aircraft that provide the pilot with information about the flight situation of that aircraft, such as altitude, airspeed and direction. They improve safety by allowing the pilot to fly the aircraft in level flight, and make turns, without a reference outside the aircraft such as the horizon. Visual Flight Rules or VFR require an airspeed indicator, an altimeter, and a compass or other suitable magnetic direction indicator. Instrument Flight Rules or IFR additionally require a gyroscopic pitch-bank (artificial horizon), direction (directional gyro) and rate of turn indicator, plus a slip-skid indicator, adjustable altimeter, and a clock. Flight into Instrument meteorological conditions or IMC require radio navigation instruments for precise takeoffs and landings.

Spatial Intelligence - Dizziness - Pilot Error

Airway or air route, or flight path, or air corridor, is a defined corridor that connects one specified location to another at a specified altitude, along which an aircraft that meets the requirements of the airway may be flown high Airways are defined with segments within a specific altitude block, corridor width, and between fixed geographic coordinates for satellites navigation system, or between ground-based Radio transmitter navigational aids (navaids; such as VORs or NDBs) or the intersection of specific radials of two navaids.

Geodesic relates to the shortest possible line between two points on a sphere or other curved surface. Geodesic is commonly a curve representing in some sense the shortest[a] path (arc) between two points in a surface, or more generally in a Riemannian manifold. The term also has meaning in any differentiable manifold with a connection. It is a generalization of the notion of a "straight line" to a more general setting.

Geodesics in general relativity generalizes the notion of a "straight line" to curved space time. Importantly, the world line of a particle free from all external, non-gravitational forces is a particular type of geodesic. In other words, a freely moving or falling particle always moves along a geodesic. In general relativity, gravity can be regarded as not a force but a consequence of a curved spacetime geometry where the source of curvature is the stress–energy tensor (representing matter, for instance). Thus, for example, the path of a planet orbiting a star is the projection of a geodesic of the curved four-dimensional (4-D) spacetime geometry around the star onto three-dimensional (3-D) space. Geodesic Curvature (wiki).

Time of Flight is a property of an object, particle or acoustic, electromagnetic or other wave. It is the time that such an object needs to travel a distance through a medium. The measurement of this time (i.e. the time of flight) can be used for a time standard (such as an atomic fountain), as a way to measure velocity or path length through a given medium, or as a way to learn about the particle or medium (such as composition or flow rate). The traveling object may be detected directly (e.g., ion detector in mass spectrometry) or indirectly (e.g., light scattered from an object in laser doppler velocimetry).

Why Are Airplane Wings Angled Backwards?? (youtube)

Aerodynamic Force is exerted on a body by the air (or some other gas) in which the body is immersed, and is due to the relative motion between the body and the gas. Aerodynamic force arises from two causes: the normal force due to the pressure on the surface of the body. The shear force due to the viscosity of the gas, also known as skin friction. Pressure acts locally, normal to the surface, and shear force acts locally, parallel to the surface. The net aerodynamic force over the body is due to the pressure and shear forces integrated over the total exposed area of the body. When an airfoil (or a wing) is moving relative to the air it generates an aerodynamic force, in a rearward direction at an angle with the direction of relative motion. This aerodynamic force is commonly resolved into two components.

Drafting in aerodynamics or slipstreaming, is a technique where two vehicles or other moving objects are caused to align in a close group reducing the overall effect of drag due to exploiting the lead object's slipstream. Especially when high speeds are involved, as in motor racing and cycling, drafting can significantly reduce the paceline's average energy expenditure required to maintain a certain speed and can also slightly reduce the energy expenditure of the lead vehicle or object.

Air Flow is the movement of air from one area to another. The primary cause of airflow is the existence of pressure gradients. Air behaves in a fluid manner, meaning particles naturally flow from areas of higher pressure to those where the pressure is lower. Atmospheric air pressure is directly related to altitude, temperature, and composition. In engineering, airflow is a measurement of the amount of air per unit of time that flows through a particular device. The flow of air can be induced through mechanical means (such as by operating an electric or manual fan) or can take place passively, as a function of pressure differentials present in the environment. Flow Rate (water, liquid).

Air Flow Meter is a device that measures air flow, i.e. how much air is flowing through a tube. It does not measure the volume of the air passing through the tube, it measures the mass of air flowing through the device per unit time. Thus air flow meters are simply an application of mass flow meters for a special medium. Typically, mass air flow measurements are expressed in the units of kilograms per second (kg/s). Air Tightness.

Vortex is a region in a fluid in which the flow is rotating around an axis line, which may be straight or curved. Torus - Vortex Shedding.

Impeller is a Rotor used to increase or decrease in case of turbines the pressure and flow of a fluid.

Helicopter Rotor is the combination of several rotary wings (rotor blades) and a control system that generates the aerodynamic lift force that supports the weight of the Helicopter, and the thrust that counteracts aerodynamic drag in forward flight. Each main rotor is mounted on a vertical mast over the top of the helicopter, as opposed to a helicopter tail rotor, which connects through a combination of drive shaft(s) and gearboxes along the tail boom. The blade pitch is typically controlled by a swashplate connected to the helicopter flight controls. Helicopters are one example of rotary-wing aircraft (rotorcraft). The name is derived from the Greek words helix, helik-, meaning spiral; and pteron meaning wing.

Coandă Effect is the tendency of a fluid jet to stay attached to a convex surface. It is named after Romanian inventor Henri Coanda, who described it as "the tendency of a jet of fluid emerging from an orifice to follow an adjacent flat or curved surface and to entrain fluid from the surroundings so that a region of lower pressure develops." Coanda was the first to recognize the practical application of the phenomenon in aircraft design.

Ground Effect is the increased lift and decreased aerodynamic drag that an aircraft's wings generate when they are close to a fixed surface. When landing, ground effect can give the pilot the feeling that the aircraft is "floating". When taking off, ground effect may temporarily reduce the stall speed. The pilot can then fly just above the runway while the aircraft accelerates in ground effect until a safe climb speed is reached. For rotorcraft, ground effect results in more power being available during hovering which allows heavier weights to be lifted. Helicopter pilots are provided with performance charts which show the limitations for hovering their helicopter in ground effect (IGE) and out of ground effect (OGE). The charts show the added lift benefit produced by ground effect. For fan- and jet-powered VTOL aircraft, ground effect when hovering can cause suckdown and fountain lift on the airframe and loss in hovering thrust if the engine sucks in its own exhaust gas, which is known as hot gas ingestion (HGI).

VTOL or a vertical take-off and landing aircraft is one that can hover, take off, and land vertically.

Rotorcraft is a heavier-than-air flying machine that uses lift generated by wings, called rotary wings or rotor blades, that revolve around a mast. Several rotor blades mounted on a single mast are referred to as a rotor.

Yaw, Pitch and Roll Aircraft Principal Axes. An aircraft in flight is free to rotate in three dimensions: Yaw, nose left or right about an axis running up and down; Pitch, nose up or down about an axis running from wing to wing; and Roll, rotation about an axis running from nose to tail. The axes are alternatively designated as vertical, transverse, and longitudinal respectively. These axes move with the vehicle and rotate relative to the Earth along with the craft. These definitions were analogously applied to spacecraft when the first manned spacecraft were designed in the late 1950s. These rotations are produced by torques (or moments) about the principal axes. On an aircraft, these are intentionally produced by means of moving control surfaces, which vary the distribution of the net aerodynamic force about the vehicle's center of gravity. Elevators (moving flaps on the horizontal tail) produce pitch, a rudder on the vertical tail produces yaw, and ailerons (flaps on the wings that move in opposing directions) produce roll. On a spacecraft, the moments are usually produced by a reaction control system consisting of small rocket thrusters used to apply asymmetrical thrust on the vehicle. Normal axis, or yaw axis — an axis drawn from top to bottom, and perpendicular to the other two axes. Parallel to the fuselage station. Transverse axis, lateral axis, or pitch axis — an axis running from the pilot's left to right in piloted aircraft, and parallel to the wings of a winged aircraft. Parallel to the buttock line. Longitudinal axis, or roll axis — an axis drawn through the body of the vehicle from tail to nose in the normal direction of flight, or the direction the pilot faces. Parallel to the waterline. Normally, these axes are represented by the letters X, Y and Z in order to compare them with some reference frame, usually named x, y, z. Normally, this is made in such a way that the X is used for the longitudinal axis, but there are other possibilities to do it. Vertical axis (yaw) - The position of all three axes, with the right-hand rule for its rotations.The yaw axis has its origin at the center of gravity and is directed towards the bottom of the aircraft, perpendicular to the wings and to the fuselage reference line. Motion about this axis is called yaw. A positive yawing motion moves the nose of the aircraft to the right. The rudder is the primary control of yaw. The term yaw was originally applied in sailing, and referred to the motion of an unsteady ship rotating about its vertical axis. Its etymology is uncertain. Transverse axis (pitch). - The pitch axis (also called transverse or lateral axis) has its origin at the center of gravity and is directed to the right, parallel to a line drawn from wingtip to wingtip. Motion about this axis is called pitch. A positive pitching motion raises the nose of the aircraft and lowers the tail. The elevators are the primary control of pitch. Longitudinal axis (roll) - The roll axis (or longitudinal axis) has its origin at the center of gravity and is directed forward, parallel to the fuselage reference line. Motion about this axis is called roll. An angular displacement about this axis is called bank. A positive rolling motion lifts the left wing and lowers the right wing. The pilot rolls by increasing the lift on one wing and decreasing it on the other. This changes the bank angle. The ailerons are the primary control of bank. The rudder also has a secondary effect on bank.

Density of Air is the mass per unit volume of Earth's Atmosphere. Air density, like air pressure, decreases with increasing altitude. It also changes with variation in temperature or humidity.

Altitude is defined based on the context in which it is used (aviation, geometry, geographical survey, sport, and many more). As a general definition, altitude is a distance measurement, usually in the vertical or "up" direction, between a reference datum and a point or object.

Elevation mainly used when referring to points on the Earth's surface, while altitude or geopotential height is used for points above the surface, such as an aircraft in flight or a spacecraft in orbit, and depth is used for points below the surface.

Wind is the flow of gases on a large scale. Fans.

Wind Direction is reported by the direction from which it originates. A northerly Wind blows from the north to the south.

Turbulence is fluid motion characterized by chaotic changes in pressure and flow velocity. It is in contrast to a laminar flow, which occurs when a fluid flows in parallel layers, with no disruption between those layers.

Clear-Air Turbulence is the turbulent movement of air masses in the absence of any visual clues, such as clouds, and is caused when bodies of air moving at widely different speeds meet.

Wind Shear is a difference in wind speed or direction over a relatively short distance in the atmosphere. Atmospheric wind shear is normally described as either vertical or horizontal wind shear. Vertical wind shear is a change in wind speed or direction with change in altitude. Horizontal wind shear is a change in wind speed with change in lateral position for a given altitude.

Thermal is a column of rising air in the lower altitudes of Earth's atmosphere, a form of atmospheric updraft. Thermals are created by the uneven heating of Earth's surface from solar radiation, and are an example of convection, specifically atmospheric convection. The Sun warms the ground, which in turn warms the air directly above it. Convection is the movement of groups of molecules within fluids such as gases and liquids, including molten rock (rheid). Convection takes place through advection, diffusion or both. Advection is the transport of a substance by bulk motion. Hot Air.

Gravity - Vacuum

Aviation Safety means the state of an aviation system or organization in which risks associated with aviation activities, related to, or in direct support of the operation of aircraft, are reduced and controlled to an acceptable level. It encompasses the theory, practice, investigation, and categorization of flight failures, and the prevention of such failures through regulation, education, and training. It can also be applied in the context of campaigns that inform the public as to the safety of air travel.

De Havilland Canada DHC-2 Beaver is a single-engined high-wing propeller-driven short takeoff and landing (STOL) aircraft developed and manufactured by de Havilland Canada. It has been primarily operated as a bush plane and has been used for a wide variety of utility roles, such as cargo and passenger hauling, aerial application (crop dusting and aerial topdressing), and civil aviation duties. Shortly after the end of the Second World War, de Havilland Canada made the decision to orient itself towards civilian operators. Based upon feedback from pilots, the company decided that the envisioned aircraft should have excellent STOL performance, all-metal construction, and accommodate many features sought by the operators of bush planes. On 16 August 1947, the maiden flight of the aircraft, which had received the designation DHC-2 Beaver, took place. In April 1948, the first production aircraft was delivered to the Ontario Department of Lands and Forests. A Royal New Zealand Air Force (RNZAF) Beaver played a supporting role in Sir Edmund Hillary's famous 1958 Commonwealth Trans-Antarctic Expedition to the South Pole. In addition to its use in civilian operations, the Beaver has been widely adopted by armed forces as a utility aircraft. The United States Army purchased several hundred aircraft; nine DHC-2s are still in service with the U.S. Air Force Auxiliary (Civil Air Patrol) for search and rescue. By 1967, in excess of 1,600 Beavers had been constructed prior to the closure of the original assembly line. Various aircraft have been remanufactured and upgraded. Additionally, various proposals have been mooted to return the Beaver to production. The Beaver's versatility and performance led to it being the preferred aircraft of bush pilots servicing remote locations in the Canadian north, and it is considered by aviation historians to be a Canadian icon. In 1987, the Canadian Engineering Centennial Board named the DHC-2 one of the top ten Canadian engineering achievements of the 20th century. The Royal Canadian Mint honoured the aircraft on a special edition Canadian quarter in November 1999, and on a 50-cent commemorative gold coin in 2008. Large numbers continue to be operational into the 21st century, while the tooling and type certificate for the Beaver have been acquired by Viking Air who continue to produce replacement components and refurbish examples of the type.

Drag - Friction

Drag is a type of friction, or fluid resistance, another type of friction or fluid friction) is a force acting opposite to the relative motion of any object moving with respect to a surrounding fluid.

Aerodynamic Drag is the fluid drag force that acts on any moving solid body in the direction of the fluid freestream flow.

Drag Coefficient is a dimensionless quantity that is used to quantify the drag or resistance of an object in a fluid environment, such as air or water. It is used in the drag equation in which a lower drag coefficient indicates the object will have less aerodynamic or hydrodynamic drag. The drag coefficient is always associated with a particular surface area.

Drag in physics sometimes called air resistance, a type of friction, or fluid resistance, another type of friction or fluid friction) is a force acting opposite to the relative motion of any object moving with respect to a surrounding fluid. This can exist between two fluid layers (or surfaces) or a fluid and a solid surface. Unlike other resistive forces, such as dry friction, which are nearly independent of velocity, drag forces depend on velocity. Drag force is proportional to the velocity for a laminar flow and the squared velocity for a turbulent flow. Even though the ultimate cause of a drag is viscous friction, the turbulent drag is independent of viscosity.

Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other. There are several types of friction: Dry friction is a force that opposes the relative lateral motion of two solid surfaces in contact. Dry friction is subdivided into static friction ("stiction") between non-moving surfaces, and kinetic friction between moving surfaces. With the exception of atomic or molecular friction, dry friction generally arises from the interaction of surface features, known as asperities. Fluid friction describes the friction between layers of a viscous fluid that are moving relative to each other. Lubricated friction is a case of fluid friction where a lubricant fluid separates two solid surfaces. Skin friction is a component of drag, the force resisting the motion of a fluid across the surface of a body. Internal friction is the force resisting motion between the elements making up a solid material while it undergoes deformation. When surfaces in contact move relative to each other, the friction between the two surfaces converts kinetic energy into thermal energy (that is, it converts work to heat). This property can have dramatic consequences. Laser-cooled ions contribute to better understanding of friction.

Skin Friction Drag is a component of profile drag, which is resistant force exerted on an object moving in a fluid. Skin friction drag is caused by the viscosity of fluids and is developed from laminar drag to turbulent drag as a fluid moves on the surface of an object. Skin friction drag is generally expressed in terms of the Reynolds number, which is the ratio between inertial force and viscous force.

Frictional Force refers to the force generated by two surfaces that contacts and slide against each other. These forces are mainly affected by the surface texture and quantity of force requiring them together. The angle and position of the object affect the volume of frictional force.

Laminar-Turbulent Transition is the process of a laminar flow becoming Turbulent, which is a flow regime in fluid dynamics characterized by chaotic changes in pressure and flow velocity. It is in contrast to a laminar flow regime, which occurs when a fluid flows in parallel layers, with no disruption between those layers.

Fluid Dynamics describes the flow of fluids (liquids and gases).

Atmosphere - Pressure - Superconductivity

Windshield is the front window generally made of laminated safety glass, a type of treated glass, which consists of two (typically) curved sheets of glass with a plastic layer laminated between them for safety, and are bonded into the window frame. Motorbike windshields are often made of high-impact acrylic plastic.

CAVU is an aeronautical term that stands for "Ceiling and Visibility Unlimited".

Why are plane windows round? (youtube)

Stress Concentration is a location in an object where stress is concentrated. An object is strongest when force is evenly distributed over its area, so a reduction in area, e.g., caused by a crack, results in a localized increase in stress. A material can fail, via a propagating crack, when a concentrated stress exceeds the material's theoretical cohesive strength. The real fracture strength of a material is always lower than the theoretical value because most materials contain small cracks or contaminants (especially foreign particles) that concentrate stress. Fatigue cracks always start at stress raisers, so removing such defects increases the fatigue strength.

Center of Mass of a distribution of mass in space is the unique point where the weighted relative position of the distributed mass sums to zero, or the point where if a force is applied it moves in the direction of the force without rotating. The distribution of mass is balanced around the center of mass and the average of the weighted position coordinates of the distributed mass defines its coordinates. Calculations in mechanics are often simplified when formulated with respect to the center of mass. It is a hypothetical point where entire mass of an object may be assumed to be concentrated to visualise its motion. In other words, the center of mass is the particle equivalent of a given object for application of Newton's laws of motion. In the case of a single rigid body, the center of mass is fixed in relation to the body, and if the body has uniform density, it will be located at the centroid. The center of mass may be located outside the physical body, as is sometimes the case for hollow or open-shaped objects, such as a horseshoe. In the case of a distribution of separate bodies, such as the planets of the Solar System, the center of mass may not correspond to the position of any individual member of the system. The center of mass is a useful reference point for calculations in mechanics that involve masses distributed in space, such as the linear and angular momentum of planetary bodies and rigid body dynamics. In orbital mechanics, the equations of motion of planets are formulated as point masses located at the centers of mass. The center of mass frame is an inertial frame in which the center of mass of a system is at rest with respect to the origin of the coordinate system. Pivot axes.

Cabin Pressurization is a process in which conditioned air is pumped into the cabin of an aircraft or spacecraft, in order to create a safe and comfortable environment for passengers and crew flying at high altitudes. For aircraft, this air is usually bled off from the gas turbine engines at the compressor stage, and for spacecraft, it is carried in high-pressure, often cryogenic tanks. The air is cooled, humidified, and mixed with recirculated air if necessary, before it is distributed to the cabin by one or more environmental control systems. The cabin pressure is regulated by the outflow valve.

Weather Wiz Kids - Weather effects on Mood

STRAPPED INTO A FALLING HELICOPTER - Smarter Every Day 154 (youtube)

Autorotation is a state of flight in which the main rotor system of a helicopter or similar aircraft turns by the action of air moving up through the rotor, as with an autogyro, rather than engine power driving the rotor. (adjust collective pinwheel).

Engineers Fly first-ever Plane with No Moving Parts. Instead of propellers or turbines, the light aircraft is powered by an 'ionic wind' -- a silent but mighty flow of ions that is produced aboard the plane, and that generates enough thrust to propel the plane over a sustained, steady flight. Space Flight.

Wingless Electromagnetic Air Vehicle uses a multitude of small electrodes covering the whole wetted area of the aircraft, in a multi-barrier plasma actuator (MBPA) arrangement, an enhancement over dual-electrode dielectric barrier discharge (DBD) systems using multiple layers of dielectric materials and powered electrodes. These electrodes are very close to one another so surrounding air can be ionized using RF AC high voltage of a few tens of kilovolts even at the standard pressure of one atmosphere. The resultant plasma contains ions that are accelerated by the Coulomb force using electrohydrodynamics (EHD) at low altitude and small velocity. The surface of the vehicle acts as an electrostatic fluid accelerator pumping surrounding air as ion wind, radially then downward, so the lower pressure zone on the upper surface and the higher pressure zone underneath the aircraft produces lift and thrust for propulsion and stability. At a higher altitude and to reach greater speeds, a magnetic field is also applied to enhance collisions between electrons and heavy species in the plasma and use the more powerful Lorentz body force to accelerate all charge carriers in the same direction along a radial high speed jet.

Ion Wind is the airflow induced by electrostatic forces linked to corona discharge arising at the tips of some sharp conductors (such as points or blades) subjected to high voltage relative to ground. Ion wind is an electrohydrodynamic phenomenon. Ion wind generators can also be considered electrohydrodynamic thrusters. The term “ionic wind” is considered a misnomer due to misconceptions that only positive and negative ions were primarily involved in the phenomenon.

Ionocraft is a device that uses an electrical electrohydrodynamic (EHD) phenomenon to produce thrust in the air without requiring any combustion or moving parts. Orbital Mechanics.

Bird Flight Mechanics

How Birds Fly Bird Flight is the primary mode of locomotion used by most bird species in which birds take off and fly. Flight assists birds with feeding, breeding, avoiding predators, and migrating. Bird flight is one of the most complex forms of locomotion in the animal kingdom. Each facet of this type of motion, including hovering, taking off, and landing, involves many complex movements. As different bird species adapted over millions of years through evolution for specific environments, prey, predators, and other needs, they developed specializations in their wings, and acquired different forms of flight. Various theories exist about how bird flight evolved, including flight from falling or gliding (the trees down hypothesis), from running or leaping (the ground up hypothesis), from wing-assisted incline running or from proavis (pouncing) behavior.
Most Birds can Fly, which distinguishes them from almost all other vertebrate classes. Flight is the primary means of locomotion for most bird species and is used for searching for food and for escaping from predators. Birds have various adaptations for flight, including a lightweight skeleton, two large flight muscles, the pectoralis (which accounts for 15% of the total mass of the bird) and the supracoracoideus, as well as a modified forelimb (wing) that serves as an aerofoil. Wing shape and size generally determine a bird's flight style and performance; many birds combine powered, flapping flight with less energy-intensive soaring flight. About 60 extant bird species are flightless, as were many extinct birds. Flightlessness often arises in birds on isolated islands, probably due to limited resources and the absence of land predators. Although flightless, penguins use similar musculature and movements to "fly" through the water, as do some flight-capable birds such as auks, shearwaters and dippers.

Advanced Robotic Bat Can Fly Like the Real Thing (youtube)

Engineers Build Robot Drone That Mimics Bat Flight.

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