Author Question: When a rock is held above the ground, we say it has some potential energy. When we let it go, it ... (Read 73 times)

chads108 · **on:** Jul 27, 2018

When a rock is held above the ground, we say it has some potential energy. When we let it go, it falls and we say the potential energy is converted to kinetic energy. Finally, the rock hits the ground. What has happened to the energy?

A) The energy goes into the ground and, as a result, the orbit of the earth about the Sun is slightly changed.
B) The energy goes to producing sound and to heating the ground, rock, and surrounding air.
C) The rock keeps the energy inside it (saving it for later use).
D) It is lost forever. Energy does not have to be conserved.
E) It is transformed back into gravitational potential energy.

Question 2

We are not yet capable of detecting life on planets around other stars. But as our technology develops, our first real chance of detecting such life will probably come from

A) sending spacecraft to study the planets up close.
B) examining spectral lines from the atmospheres of distant planets.
C) examining high-resolution images of the planets made by orbiting telescopes.
D) determining the orbital properties of the planets.