# Homework Help: Universal Gravitation homework

1. Jan 28, 2014

### yiyi

1. The problem statement, all variables and given/known data

In the not-too-distant future astronauts will travel to mars to carry out scientific explorations. As part of their mission, it is likely that a "geosynchronous" satelite will be placed
above a given point on the Martian equator to facilitate communcations. At what altitude above the surface of mars should such a satellite orbit? (the Martian day is 24.6229 hours. other relevant information can be found in appendix c.) At what altitude above the suface of mars should such a satellite orbit?

2. Relevant equations

I know that we should use Universal Gravitation (F = GmM1/R^2).

3. The attempt at a solution

r = (GMT/2pi)^.5
i did this to solve for the radius, converting the Maritan day into seconds first.

2. Jan 28, 2014

### collinsmark

Hello yiyi,

Welcome to Physics Forums!

You will have to show more work. Something isn't quite right to me with your "r = (GMT/2pi)^.5" answer. Perhaps if you show some of your work we can help find what went wrong.

As a hint though, set the gravitational force equal to the centripetal force and solve for r.

3. Jan 28, 2014

### yiyi

I think I just did some mathematical calculations wrong. Thanks for the help!