| A | B |
|---|
| motion | an object's change in position relative to a reference point |
| displacement | the change in position of an object |
| speed | the distance traveled divided by the time interval during which the motion occurred |
| velocity | the speed of an object in a particular direction |
| acceleration | the rate at which velocity changes over time |
| force | an action exerted on a body in order to change the body's state of rest or motion; has magnitude and direction |
| net force | a single force whose external effects on a rigid body are the same as the effects of several actual forces acting on the body |
| friction | a force that opposes motion between two surfaces that are in contact |
| static friction | the force that resists the initiation of sliding motion between two surfaces that are in contact and at rest |
| kinetic friction | the force that opposes the movement of two surfaces that are in contact and are sliding over each other |
| centripetal acceleration | the acceleration directed toward the center of a circular path |
