Gravitational potential energy

[bearhug]

A 5.2 kg particle and a 2.4 kg particle have a gravitational attraction of magnitude 2.3E-12 N.
Gravitational potential energy is -4.40e-11J and r=19.03m

If you were to triple the distance between these particles, how much work is done by you on the particles?

My biggest problem here is that I don't know what equation I should use to find the work done. My book doesn't explain it very well. The first part of the question I figured out fine but this is where I'm stuck. Any help would be greatly appreciated.

 

[OlderDan]

What is the definition (not the equation) of gravitaional potential energy? Hint: it has something to do with work.

 

[bearhug]

The work done on the system is a change in gravitational potential energy.

 

[bearhug]

Nevermind, what I just posted is what I needed to know, I figured it out. Thanks for your hint.