| A | B |
|---|
| Force | a push or pull on an object |
| contact force | a push or pull on an object by another object that is touching it |
| noncontact force | a force one object can apply to another without touching it |
| gravity | an attractive force that exists between objects that have mass |
| mass | the amount of matter in an object |
| weight | the gravitational force acting on an object |
| friction | the force that resists the motion of two surfaces that are touching |
| Static friction | prevents surfaces from sliding past each other |
| Sliding friction | opposes the motion of surfaces sliding past each other |
| Fluid friction | friction between a surface and any fluid that flows |
