How Do You Calculate the Gravitational Acceleration of a Satellite in Orbit?

[Meroko]

Homework Statement

Synchronous communications satellites are placed in a circular orbit that is 3.59 X 10^7m above the surface of the earth. What is the magnitude of the acceleration due to gravity at this distance?

Homework Equations

F=G M1M2 / R^2/ mp
g= GMe / r^2
r= Re + H
w=mg
g=w/m

The Attempt at a Solution

I tried to put the numbers in the "g= GMe / r^2" equation, which turns out to be
g= 6.673 X 10^-11 X 5.9742 X 10^24 /( 3.59 X 10^7)^2

But the answer that I got is wrong. Can someone please help me fix my mistakes and help me get the right answer?

 

[Phyisab****]

Consider the third equation in your list of relevant equations.