Which of the following is an example of kinetic energy?

Kinetic energy is defined as the energy that an object possesses due to its motion. The correct example in this context is a ball rolling down a hill, as it is in motion and possesses kinetic energy due to its velocity. The speed and mass of the ball contribute to its kinetic energy, which can be calculated using the formula KE = 1/2 mv², where m is the mass and v is the velocity of the moving object.

In contrast, a stationary ball does not possess kinetic energy because it is not moving. A compressed spring and a stretched rubber band both represent potential energy, as they are in a state of tension or compression and have the potential to do work when released, but they are not moving in those states. Therefore, the ball rolling down the hill clearly exemplifies kinetic energy, distinguishing it from the other options that describe stored energy rather than energy in motion.