The strength of the gravitational field of a source mass can be measured by the magnitude of the acceleration due to gravity at a field point. thus the gravitational field strength at a point depends on the distance from the source mass. for this problem assume that earth’s mass is concentrated at its center and that earth has a radius of re = 6,378 km at sea level and a mass of me = 5.972×1024 kg. ignore any forces due to earth’s rotation or due to other astronomical bodies.