speed of a satellite

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; R_E= 6.37·10³ km M_E= 5.98·10²⁴ kg

Answer 1

mv²/R = GM_em/R² Rearranging

v = sqrt(GM_e/R) where G is 6.67 x 10^-11 Nm²/kg², and R = 3.89*(6.37x10⁶ m)