Question

Find the speed of a satellite in a circular orbit around the Earth with a radius 3.89 times the mean radius of the Earth; RE= 6.37·103 km ME= 5.98·1024 kg

Answer 1

F = m a = m v^2/R = G m Me / R^2

so
v^2 = G Me /3.89R = 6.67*10^-11 * 5.98*10^24 / (3.89 * 6.37 *10^6)
(note 10^3 km = 10^6 meters)