Determining Satellite's Altitude and Period Using Kepler's Laws

[featherua08]

Homework Statement

A satellite moves in a circular orbit around Earth at a speed of 4505 m/s.

a) Determine satellite's altitude above surface of the Earth.
b) Determine the period of satellite's orbit.

Homework Equations

I'm not sure about equations for the altitude, but I know the period has something to do with Kelper's laws &

T^2=(4pie^2/GMe)r^3=KeR^3

The Attempt at a Solution

My attempt was to use the above equation with G=6.67x10^-11 & Me=6378.1
It wasn't right.

 

[Kurdt]

I think this will probably have more to do with circular motion than Kepler's laws.

 

[D H]

My attempt was to use the above equation with G=6.67x10^-11 & Me=6378.1
It wasn't right.

What units are those numbers in? You have to make sure the values you use are consistent with respect to units. Those numbers are not.