| A | B |
|---|
| Position | The location of an object. |
| Motion | A change in an object’s position over time. |
| Frame of reference | A group of objects from which a position or motion is measured. |
| Speed | How fast an object’s position changes with time at any given moment. |
| Velocity | The speed and direction of a moving object. |
| Acceleration | Change in velocity with respect to time. |
| Momentum | The mass of an object multiplied by its velocity. |
| Force | Any push or pull by one object on another. |
| Friction | A force that opposes the motion of one object moving past another. |
| Balanced force | Forces that act together without changing its motion. |
| Unbalanced force | A force that causes an object to change its motion. |
| Action force | The initial push or pull of one object on another object. |
| Reaction force | The push or pull of a second object back on the object that started the push or pull. |
