If you mean the force of gravity, the force of gravity on Earthis equal to the mass of an object, times Earth's gravitationalfield (which is about 9.8 newton/kilogram).The gravitational forcebetween ANY two masses, on the other hand, is given by:force = G m1 m2 / r squaredWhere m1 and m2 are the two masses involved, "r" is the distancebetween them, and "G" is the universal gravitational constant.