Final answer:
When a very light object like a ping-pong ball hits a very heavy object like a bowling ball head-on in an elastic collision, the light object will bounce back with a slightly lower speed than its initial speed.
Step-by-step explanation:
When a very light object like a ping-pong ball hits head-on a very heavy object like a bowling ball that is at rest, and the collision is elastic, the light object bounces back with a speed that is slightly less than its initial speed. This can be explained using the principle of conservation of momentum.
In an elastic collision, both the momentum and kinetic energy are conserved. Since the bowling ball is at rest initially, it has zero momentum. After the collision, the ping-pong ball gains momentum in the backward direction, causing it to bounce back.
However, due to conservation of kinetic energy, the final speed of the ping-pong ball will be slightly less than its initial speed. This is because some of the initial kinetic energy is converted into other forms of energy during the collision, such as sound or deformation of the objects.