In February 1995, a total of 54.3 billion kW-h of electrical energy was generated by nuclear power plants in the United States. At the same time, the population of the United States was about 255 million people. If the average American has a mass of 60 kg, and if the entire energy output of all nuclear power plants was diverted to supplying energy for a single giant elevator, estimate the height h at which the entire population of the country could be lifted by the elevator. In your calculations, assume that 25% of the energy goes into lifting the people; assume also that g is constant over the entire height h.