| A | B |
|---|
| force | a push or a pull |
| gravity | force of attraction between two objects due to mass |
| newton | unit used to express force |
| rolling | friction between wheels and a surface |
| net force | combination of all forces acting on an object |
| velocity | speed in a certain direction |
| friction | force opposing motion between touching surfaces |
| motion | changing position over time, in relation to a reference point |
| speed | rate at which an object moves |
| weight | measure of the force of gravity |
| mass | amount of matter in an object |
| balanced | forces that produce a net force of zero |
| acceleration | rate at which velocity changes |
| static | friction experienced by objects that are not moving |
| kinetic | friction experienced by objects that are in motion |
| lubricant | a substance that decreases friction |
