| A | B |
|---|
| force | a push or pull put on an object |
| net force | the overall force on an object when all the individual forces acting on an object are added together |
| unbalanced force | a nonzero net force which changes an object's motion |
| balanced forces | a net force of zero which does not change an object's motion |
| inertia | the tendency of a moving object to continue in a straight line or a stationary object to remain in place ( an object at rest wants to stay at rest, an object in motion wants to stay in motion) |
| mass | the amount of matter in an object |
| newton | a unit of force (kg m/s2) |
| friction | a force that is put out when two substances are rubbed together |
| sliding friction | friction that occurs when one solid surface slides over another |
| rolling friction | friction that occurs when an object rolls over a surface |
| fluid friction | friction that happens as an object moves through a fluid |
| gravity | a force that pulls objects towards each other |
| 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 felt by objects as they fall through air |
| terminal velocity | the maximum velocity a falling object can hit |
| weight | a measure of the force of gravity on an object |
| momentum | the product of an object's mass and velocity |
| law of conservation of momentum | the rule that the total momentum of objects in an interaction does not change |
| centripetal force | a force that causes an object to move in circles |
