A 2.0 kilogram possum hangs from a tree limb 5 meters above the ground. Assuming that the gravitational potential energy is zero at y = 0 and that g is 9.8 meters per second squared, what is the gravitational potential energy, to the nearest joule, of the possum-Earth system if we take the reference point y = 0 to be 1.0 meters above the limb?