| A | B |
|---|
| force that acts only when one system touches another | contact force |
| forces whose push and pull and cancels each other out | balanced force |
| force exerted on objects by a field | field force |
| a system where one force is larger than the other | unbalanced force |
| A push or pull on a system | force |
| the tendency of an object to resist change in motion | inertia |
| an object accelerated by the force of gravity alone | freefall |
| for every external force, there is an equal but opposite force | law of action-reaction |
| maximum velocity a falling object can reach | terminal velocity |
| a contact force that opposes the movement of objects past each other | friction |
| a form of friction exerted by a fluid on an object moving in relation to the fluid | drag |
| weight | kg m/s2 |
| acceleration due to gravity | 9.8 m/s2 |
| velocity | m/s |
| acceleration | m/s2 |
| mass | kg |
| Gravitational constant | N m2/kg2 |
| law of motion states that an object at rest will stay at rest | 1st Law of motion |
| law of motion states that the change in motion is proportional to the force acting on the system | 2nd Law of motion |
| law of motion states that for every action there is an equal and opposite reaction | 3rd Law of motion |
