I really don't even understand what this problem is talking about! If someone could just point me in the right direction, I would appreciate it!

A satellite is placed in a noncircular orbit about the Earth. The farthest point of its orbit (

*apogee*) is 4 Earth radii from the center of the Earth, while its nearest point (

*perigee*) is 2 Earth radii from the Earth's center. If we define the gravitational potential energy

*U*to be zero for an infinite separation of Earth and satellite, find the ratio

*U perigee/U apogee*.

Thanks!