**1. The problem statement, all variables and given/known data**

A satellite of mass 45.5 kg orbiting the earth moves from an orbit of 7271 km to an orbit of 7356 km.

what is the work done by all forces acting on it?

**2. Relevant equations**

U=GMm/r

**3. The attempt at a solution**

I calculated the total energies of the satellite in both orbits which is -1/2GMm/r

This gave -1.2458Gj for the lower orbit and -1.2315 for the higher one.

Should the difference be the total work done?

http://ift.tt/1lPENqi