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Physics Definitions

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Nobody:
These are all the physics definitions that you will need...
Also, it will help you to understand the topics better.  ;)

Rotational Motion

Rotational Inertia: That property of an object to resist any change in its state of rotation. If at rest the body tends to remain at rest; if rotating, it tends to remain rotating and will continue to do so unless acted upon by a net external torque.

Torque: The product of force and lever-arm distance, which tends to produce rotation.

Center of Mass: The average position of mass or the single point associated with an object where all its mass can be considered to be concentrated.

Center of Gravity: The average position of weight or the single point associated with an object where the force of gravity can be considered to ace. Usually the same place as the center of mass.

Equilibrium: The state of an object when not acted upon by a net force or net torque. An object in equilibrium may be at rest or moving at uniform velocity; that is, not accelerating.

Centripetal Force: A center-seeking force that causes an object to follow a circular path
F = (mv^2)/r

Centrifugal Force: An outward force that is due to rotation. In an inertial frame of reference, it is fictitious in the sense that it doesn't act on the rotating object but on whatever supplied the centripetal force; it is the reaction to the centripetal force. In a rotating frame of reference, it does act on the rotating body and is fictitious in the sense that it is not an interaction with an agent or entity such as mass or charge but is a force in itself that is solely a product of rotation; it has no reaction-force counterpart.

Angular Momentum: A measure of an object's rotation about a particular axis; more specifically, the product of its rotational inertia and rotational velocity. For an object that is small compared to the radial distance, it is the product of mass speed, and radial distance of rotation.
Angular Momentum = rotational inertia x rotational velocity (mvr)

Conservation of Angular Momentum: When no external torque acts on an object or a system of objects, no changes of angular momentum takes place. Hence, the angular momentum before an event involving only internal torques is equal to the angular momentum after the event

to be continued...  ;)

nid404:
+ rep  ;)

Nobody:

--- Quote from: ~Xena~ on July 12, 2010, 06:08:41 pm ---+ rep  ;)

--- End quote ---
Thank you. ;)
did you read them, ALL?

Gravity

Kepler's Laws of Planetary Motion:
1] Each planet moves in an elliptical orbit with the sun at one focus
2] The line form the sun to any planet sweeps out equal areas of space in equal time intervals
3] The squares of the times of revolution (days, months or years) of the planets are proportional to the cubes of their average distances from the sun.

Law of Universal Gravitation: Every mass in the universe attracts every other mass with a force that for two masses is directly proportional to the product of their masses and inversely proportional to the square of the distance separating them
F = (G(m1*m2))/d^2

Inverse-Square Law: A law relating the intensity of an effect to the inverse square of the distance from the cause. Intensity ~ 1/distance`2
Gravity follows an inverse-square law, as do the effects of electric, magnetic, light, sound, and radiation phenomena

Weightlessness:condition wherein gravitational pull appears to be A lacking.

Spring Tide: A high or low tide that occurs when the sun, earth, and moon are all lined up so that the tides due to the sun and moon coincide, making the high tides higher than average and the low tides lower than average

Neap Tide: A tide that occurs when the moon is midway between new and full, in either direction. Tides due to the sun and moon partly cancel, making the high tides lower and the low tides higher than average.

Gravitational Field: The space surrounding a massive body in which another mass experiences a force of attraction

Black Hole: The configuration of a massive star that has undergone gravitational collapse, in which gravitation at the surface is so intense that even the star's own light cannot escape.

Big Bang: The primordial explosion that is thought to have resulted in the expanding universe

Stability: In order for an object to be stable, its center of gravity must lie directly above a point of support

The state of motion of the center of mass in a system can only be changed by forces outside the system

Escape Speed: That speed which is sufficient to propel an object away from a planet, or any object

Tides: Tides are caused by the variation of force on the earth exerted by the moon (and the sun)
The effect of the moon is about 4 times greater than that of the sun.

Nobody:
Vibrations and Waves

Summary of Terms:

Sine Curve: A wave form traced by simple harmonic motion that is uniformly moving in a perpendicular direction, like the wavelike path traced on a moving conveyor belt by a pendulum swinging at right angles about the moving belt.

Amplitude: For a wave or vibration, the maximum displacement on either side of the equilibrium (midpoint) position.

Wavelength: the distance between successive identical parts of a wave

Frequency: For a body undergoing simple harmonic motion, the number of vibrations it makes per unit time. For a series of waves, the number of waves that pass a particular point per unit time.
Frequency = 1/Period -or- Period = 1/Frequency
hertz (Hz): unit of frequency; one vibration per second is 1Hz

Period: The time required for a vibration or a wave to make a complete cycle

Wavespeed: The speed with which waves pass by a particular point frequency x wavelength

Nobody:
Sound

Summary of Terms

Infrasonic: A sound frequency too low to be heard by the normal human ear. i.e. below 20Hz

Ultrasonic: A sound frequency to high to be heard by the normal human ear. i.e. about 20kHz

Compression: Condensed region of the medium through which a longitudinal wave travels.

Rarefaction: Rarefied region, or region of lessened pressure, of the medium throughout which a longitudinal wave travels.

Reverberation: Re-echoed sound.

Refraction: The bending of a wave through either a nonuniform medium or from one medium to another, caused by differences in wave speed.

Forced Vibration: The setting up of vibrations in an object by a vibrating force.

Natural Frequency: A frequency at which an elastic object naturally tends to vibrate, so that minimum energy is required to produce a forced vibration or to continue vibration at that frequency.

Resonance: The result of forced vibrations in a body when an applied frequency matches the natural frequency of the body.

Beats: A series of alternate reinforcements and cancellations produced by the interference of two sets of superimposed waves of different frequencies, heard as a throbbing effect in sound waves.

Carrier Wave: The wave, usually of radio frequency, whose characteristics are modified in the process of modulation.

Modulation: The process of impressing one wave system upon another of higher frequency.

Amplitude Modulation: A type of modulation in which the amplitude of the carrier wave is varied above and below its normal value by an amount proportional to the amplitude of the impressed wave.

Frequency Modulation: A type of modulation in which the frequency of the carrier wave is varied above and below its normal frequency be an amount that is proportional to the amplitude of the impressed signal. In this case, the amplitude of the modulated carrier wave remains constant.

Transverse Wave: A wave in which the individual particles of a medium vibrate from side to side perpendicularly to the direction in which the wave travels. (Strings)

Longitudinal Wave: A wave in which the individual particles of a medium vibrate back and forth in the direction in which the wave travels. (Sound)

Interference Pattern: The pattern formed by superposition of different sets of waves that produces mutual reinforcement in some places and cancellation in others.

Standing Wave: A stationary wave pattern formed in a medium when two sets of identical waves pass through the medium in opposite directions.

Doppler Effect: Change in frequency of sound or lighter due to relative motion of source and receiver.

Bow Wave: The V-shaped wave made by an object moving across a liquid surface at a speed greater than the wave velocity.

Shock Wave: The cone-shaped wave made by an object moving at supersonic speed through a fluid.

Sonic Boom: The loud sound resulting from the incidence of a shock wave.

more coming up!  ;)

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