| A | B |
|---|
| velocity | speed in a given direction |
| unbalanced force | force which changes an object's motion |
| speed | distance an object travels in one unit of time |
| rolling friction | friction that occurs when an object rolls over a surface |
| newton | unit of measure that equals the force required to accelerate one kilogram of mass at 1 meter per second per second |
| reference point | a place or object used for comparison to determine if something is in motion |
| motion | state in which one object's distance from another is changing |
| International System of Units | system of measurements |
| meter | basic SI unit of length |
| gravity | force that pulls objects toward earth |
| free fall | motion of a falling object when the only force acting on it is gravity |
| acceleration | rate at which velocity changes |
| force | push or pull exerted on an object |
| net force | overall force on an object when all the individual forces acting on an object are added together |
| balanced forces | equal forces acting on an object in opposite directions |
| inertia | tendency of an object to resist any change in its motion |
| mass | amount of matter in an object |
| friction | force that one surface exerts on another when the 2 rub against each other |
| sliding friction | friction that occurs when one solid surface slides over another |
| fluid friction | friction that occurs as an object moves through a fluid |
| projectile | an object that is thrown |
| air resistance | fluid friction experienced by objects falling through the air |
| terminal velocity | maximum velocity a falling object can achieve |
| weight | force of gravity on an object at the surface of a planet |
