Physics
posted by Tanveer .
The moon has a period of 27.3 days and a mean distance of 3.90 x 10^5 km from the center of Earth.
a) Use Kepler's laws to find the period of a satellite in orbit 6.70 x 10^3 km from the center of Earth
 I was able to do this and the answer i got was: 88.6 mins, but was stuck on the 2nd part of this question, which is below:
b)How far above Earth's surface is this satellite?

You have the mean distance from the center of Earth. Normally, one might subtract the thickness of the Earth from the center to get the distance from the Surface .

you have to subtract the radius of earth from the total radius
so:
6.7x10^36.38x10^3
=0.4 km
or
=400 m