Mechanical Energy- Geosynchronous Orbit

[hsphysics2]

Homework Statement

What is the total mechanical energy of a 290 kg satellite in a geosynchronous orbit around the Earth?

Homework Equations

W= K + U_G where K= 1/2 (mv²) and U_G= -(GmM)/r
F_c= ma_c where a_c= v²/r

The Attempt at a Solution

I think the geosynchronous part is what is throwing me off. What would the radius be so I can solve for the initial speed.

 

[AATroop]

I don't want to throw you off, but I think it might be easier to find the initial speed first then find the radius. It's a geosynchronous orbit, so what do you know about its period?