posted by jawn .
A spaceship of mass m travels from the Earth to the Moon along a line that passes through the center of the Earth and the center of the Moon.
(a) At what distance from the center of the Earth is the force due to the Earth five times the magnitude of the force due to the Moon?
mass of moon,mass of earth, distance from moon to earth are known
5GMe/r^2=GMmoon/(distance moon orbit-r)^2
solve for r.