| A | B |
|---|
| balanced forces | equal forces acting on an object in opposite directions |
| gravity | the force that pulls objects toward each other |
| sliding friction | friction that occurs when one solid surface slides over another |
| force | a push or pull exerted on an object |
| unbalanced force | a nonzero net force that changes an objects motion |
| law of conservation of momentum | the rule that the total momentum of objects in an interaction does not change |
| free fall | the motion of a falling object when the only force acting on it is gravity |
| fluid friction | friction that occurs as an object moves through a fluid |
| rolling friction | friction that occurs when an object rolls over a surface |
| terminal velocity | the maximum velocity a falling object achieves |
| friction | a force that one surface exerts on another when the two rub against each other |
| centripetal force | a force that causes an object to move in a circle |
| momentum | the product of an objects mass and its velocity |
| newton | a unit of measure that equals the force required to accelerate one kilogram of mass at a rate of one meter per second per second |
| inertia | the tendency of a moving object to continue in a straight line or a stationary object to remain in place |
| satellite | any object that travels around another object in space |
| air resistance | the fluid friction experienced by objects falling through air |
| centrifugal force | in circular motion |
| projectile | an object that is thrown |
| net force | the overall force on an object when all of the individual forces acting on an object are added together |
