At 11:00 AM on September 7, 2001, more than one million British school children jumped up and down for one minute to simulate an earthquake. (a) Find the energy stored in the children's bodies that was converted into internal energy in the ground and their bodies and propagated into the ground by seismic waves during the experiment. Assume that 1 200 000 children of average mass 33.0 kg jump 15 times each, raising their centers of mass by 28.0 cm each time and briefly resting between one jump and the next.