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Physics Unit 3
Momentum & Energy
Question | Answer |
---|---|
momentum | the product of the mass of an object & its velocity |
impulse | the product of the force acting on an object & the time during which it acts |
impulse-momentum relationship | impulse is equal to the change in momentum of the object that the impulse acts upon |
Law of Conservation of Momentum | in the absence of an external force, the momentum of a system remains unchanged; the momentum before an event is equal to the momentum after the event |
elastic collision | objects rebound without lasting deformation or the generation of heat |
inelastic collision | objects become distorted, generate heat, & possibly stick together |
work | the product of the force & the distance moved by the force |
power | the rate at which energy is expended; work done over the time interval |
energy | the property of a system that enables it to do work |
mechanical energy | energy due to the position or movement of something |
potential energy | energy that something possesses because of its POSITION |
kinetic energy | energy that something possesses because of its MOTION |
work-energy theorem | the work done on an object equals the change in the kinetic energy of the object |
Law of Conservation of Energy | energy cannot be created or destroyed; it may be transformed from one form into another, but the total amount of energy never changes |
machine | a device, such as a lever or pulley, that increases/decreases a force or simply changes the direction of a force |
Conservation of Energy | the work output of any machine cannot exceed the work input |
lever | a simple machine consisting of a rigid rod pivoted at a fixed point called the fulcrum |
efficiency | the % of the work put into a machine that is converted into useful work output; useful energy output divided by total energy input |