A ball falls onto a horizontal surface and rebounds elastically. During the very brief interval when it is touching the surface, what happens to the ball's kinetic energy?
- AMost of the kinetic energy is lost as heat and sound.
- BThe kinetic energy decreases to zero and then returns to its original value.
- CThe kinetic energy remains constant because it is an elastic collision.
- DThe kinetic energy remains constant in magnitude but changes direction.