Change in energy in orbiting satellite.

[Gianf]

Homework Statement

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?

Homework Equations

U=GMm/r

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?

 

[rude man]

Homework Statement

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?

Homework Equations

U=GMm/r

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?

It says find the work done by all the forces acting on it.

Contemplate the possibility that this is a 'trick' question.

 

[Gianf]

I've been thinking about this question all day... still don't get it
what would the trick be?

 

[rude man]

Sorry, I think I misread the question. Actually, it's a bit misty. My reading of it now is that there was a circular orbit of 7272 km which gets moved to a NEW circular orbit of 7356 km.

Just use conservation of energy but remember to include potential and kinetic energies.