Newton's law of gravity states that the force on an object by the Earth follows an inverse square law: 0 2 E g m m F G x ? ? where G is a constant (the universal gravitational constant), E m is the mass of the Earth, 0 m is the mass of the object, and x is the distance from the center of the earth to the center of the object. How much work is done moving the object from x ? ? to x ? R ?