Question

A satellite of mass 6500 kg orbits the earth in a circular orbit of radius of 7.5 106 m (this is above the earth's atmosphere).the mass of the earth is 6.0 1024 kg. what is the speed of the satellite?

Answer 1

The two forces, centripetal force and gravity are equal 

So, G M m / r^2 = (m V^2) / r 

so sqrt (GM/r)= V 

G is a gravitational constant which is G=6,67.10exp(-11) 

Sqrt (6.67 x 10^-11) (6 x 10^24)/7.5 x 10^6

so V= 7.30479295e9 or 7305 m/s