Gravity and Rotation 7?

Question

Calculate the force of gravity on a spacecraft 25600 km (4 earth radii) above the Earth's surface if its mass is 1200 kg.

Answer should be in N (toward the earth).

Answer 1

Force of gravity

F = G Me ms / (Re+h)^2 Newtons towards earth -its attractive

ms = 1200 kg, G= 6.67*10^-11 MKS, h = 4Re
Re =6400*10^3 meter Me = 6 * 10^24 kg

F = G Me ms / 25 (Re)^2

F = 6.67*10^-11* 6 * 10^24 *1200 / 25 (6400*10^3)^2

F = 6.67 *6 * 10^15 *12 / 25 *64 64*10^10
F = 468.984 newtons