| A | B |
|---|
| force | A push or pull placed on an object |
| net force | Overall force on an object when all the individual forces acting on an object are added together |
| unbalanced forces | A non-zero net force that changes an object's motion |
| balanced forces | Equal forces acting on an object in opposite directions |
| inertia | Tendency of a moving object object to remain in place. |
| newton | A unit omeasure that equals the force required to accelerate one kilogram f of mass at 1 meter per second. |
| friction | Force that opposes the motion of one surface as it moves across another surface. |
| sliding friction | Friction that occurs when one solid surface slides over another. |
| rolling friction | Friction that occurs when an object rolls over a surface. |
| gravity | The attractive force between two objects; its magnitude depends on their masses and the distance between them. |
| free fall | The motion of a falling object when the only force acting on it is gravity. |
| projectile | An object that is thrown. |
| air resistance | The fluid friction experienced by objects falling through the air. |
| terminal velocity | The maximum velocity a falling object can achieve. |
| law of universal gravitation | Says that the force of gravity acts between all objects in the universe. |
