Joe has a weight of 900 N (about 204 lb) when he is standing on the surface of the Earth. What would his weight (the gravitational force due to the Earth) be if he tripled his distance from the center of the Earth by flying in a spacecraft?
gravitational force is an inverse-square relationship
three times the distance means ... (1/3)^2 the force
1/9 * 900 N = ?