Question

which is the best example of the law of conservation of energy?
a basketball stops bouncing because its energy disappears.
a rolling skateboard slows down because some of its kinetic energy changes to heat.
a falling book hits the ground and all of its energy is destroyed.
a toy car gains speed as it moves down a ramp because the ramp creates energy.

Explanation:

The law of conservation of energy states that energy cannot be created or destroyed, only converted from one form to another. A rolling skateboard slows down because some of its kinetic energy changes to heat due to friction, which is consistent with energy conservation. The other options violate the law as they suggest energy disappearance, destruction, or creation.

Answer:

A rolling skateboard slows down because some of its kinetic energy changes to heat.