| A | B |
|---|
| net force | the combination of all the forces acting on an object |
| balanced forces | forces acting on an object that combine and form a net force of zero |
| unbalanced forces | forces acting on an object that combine and form a net force that is not zero |
| Newton's first law of motion | if the net force on an object is zero the motion of the object does not change |
| inertia | the tendency of an object to resist a change in its motion |
| Newton's second law of motion | the acceleration of an object is equal to the net forces acting on the object divided by the object's mass |
| circular motion | any motion in which an object is moving along a curved path |
| centripetal force | in circular motion a force that acts perpendicular to the direction of motion, towards the center of the curve |
| Newton's third law of motion | when one object exerts a force on a second object, the second object exerts an equal force in the opposite direction on the first object |
| force pair | the force two objects apply to each other |
| momentum | a measure of how hard it is to stop a moving object |
| law of conservation of momentum | the total momentum of a group of objects stays the same unless outside forces act on the objects. |
