How to calculate g (geosync orbit)

[GreatEscapist]

Homework Statement

Communications satellites are placed in a circular orbit where they stay directly over a fixed point on the equator as the Earth rotates. These are called geosynchronous orbits. The altitude of a geosynchronous orbit is 3.58e7 m.

Homework Equations

v=2∏r/T

a=(v^2)/r

The Attempt at a Solution

In the previous problem, I was asked to calculate the period of the satellite, which is obviously 24 hours.

I figure that g is another form of radial acceleration (both point to the center of earth).

Therefore, I calculated v using the period equation. Once I got v I used the radial acceleration equation to arrive at my answer for g.

It's wrong though- can anyone explain why and set me on the right track?

 

[voko]

Your method is correct. It must be some numeric mistake that you made.

 

[Cbray]

Did you add on the radius of the Earth to the orbit?