Suppose the moon has a radius of R miles and a payload weighs P pounds at the surface of the moon (at a distance of R miles from the center of the moon). When the payload is x miles from the center of the moon (x 2 R), the force required to overcome the gravitational attraction between the moon and the payload is given by the following relation: . _ _ R213 requlred force 7 f(x) 7 7 pounds For example, the amount of work done raising the payload from the surface of the moon (i.e., x = R) to an altitude of R miles above the surface of the moon (i.e., x 2 2R) is b 2 work =f x} dx 7 dX = % milepounds a How much work would be needed to raise the payload from the surface of the moon (Le.r x : R) to the "end of the universe"? work = x mile-pounds