4: Momentum (Ch6)

When a moving object hits another object, some or all of the momentum of the of the first object if transferred to the object that is the that got hit. If only some of the momentum is transferred, the rest of the momentum stays with the first object. A example is that a cue ball hits a billiard ball so that the billiard ball starts moving and the cue ball stops, because the momentum was transferred. This is an example of the Law of Conservation of Momentum. This law applies whether the objects stick together or bounce off each other after they collide. The billiard ball and the cue ball are also an example of an action and reaction force.