A rock held above the ground has potential energy. As the rock falls, this potential energy is converted to kinetic energy. Finally, the rock hits the ground and stays there. What has happened to the energy?
A)The energy goes to producing sound and to heating the ground, rock, and surrounding air.
B)It is transformed back into gravitational potential energy.
C)The rock keeps the energy inside it in the form of mass- energy.
D)The energy goes into the ground, and as a result, the orbit of the Earth about the Sun is slightly changed.

Question

Quizplus · Accepted Answer

When the rock hits the ground, the potential energy is converted into kinetic energy, which creates sound and heats up the ground, rock, and surrounding air. The energy is not transformed back into gravitational potential energy, as the rock is no longer held above the ground. The energy is also not kept inside the rock in the form of mass-energy, as the mass of the rock remains the same before and after the fall. The energy is not significant enough to change the orbit of the Earth about the Sun.

A Rock Held Above the Ground Has Potential Energy