Question

which two objects have stored energy A)a ball rolling on the ground B) a small rock sitting on top of a big rock C)a stretched rubber band D) a stone lying on the ground

Answer 1

B). a small rock sitting on top of a big rock has a little bit of
stored gravitational potential energy

C). a stretched rubber band has some stored elastic energy

Answer 2

B) a small rock sitting on top of a big rock C)a stretched rubber band

Explanation: Stored energy is also known as potential energy. This is defined as the energy possessed by an object that is stationary, i.e an object that is not in motion.

A stretched rubber band has elastic potential energy.

A small rock sitting on top of a big rock has gravitational potential energy because it is stationary and it is located at a certain height above the earth's surface.

However, taking the earth's surface as a reference, the stone lying directly on the earth's surface does not have any potential energy even though it is stationary; reason being that it is at a zero height from the earth's surface. This claim can be justified from the simple formula E=mgh which is used to calculate gravitational potential energy. When height h = 0, then consequently the equation reduces to zero, i.e. potential energy E = 0