| A | B |
|---|
| Displacement | distance moved in a particular direction |
| Velocity | rate of change of displacement |
| Speed | rate of change of distance |
| Acceleration | rate of change of velocity |
| Average | over a period of time |
| Instantaneous | at one particular time |
| Relative velocity | the velocity of an item in comparison to another |
| Force | can deform, stretch, or compress a body; causes accelaration |
| Mass | amount of material in a body |
| Weight | the gravitational force experienced by a body |
| Tension | force that arises in a body when it is stretched; is a result of electromagnetic interactions between the molecules of the material making up the string |
| Extension | difference between normal and stretch lengths |
| Normal reaction (contact force) | perpendicular to body exerting force |
| Drag force | forces that oppose the motion of a body through a fluid |
| Upthrust | upward force experienced by object placed in liquid |
| Friction | arises when one body slides over another |
| Equilibrium | when the net force on a body is zero |
| Terminal velocity | when the acceleration is zero and a body moves at a maximum constant velocity |
| Momentum | the mass of a body times its velocity |
| Impulse | change in momentum |
| Work | the product of the force times the distance moved by its point of application in the direction of the force |
| Elastic collision | collision when no mechanical energy is lost |
| Totally inelastic collision | large amount of mechanical energy is lost but total momentum is conserved and the objects join together |
| Inelastic collision | some energy is lost but objects do no join together. Total momentum is conserved. |
| Power | at which energy is transferred (rate at which work is done) |
| Efficiency | ratio of useful energy to total energy transfer |
