Asatellite 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?

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 

the average speed is 24.57 km/hr

the answer would be c