A friend suggests that everone in the world simultaneously jumping off a high platform could cause an earthquake. "Yeahright." you say. Assume all 6.5 billion inhabitants(average mass 70kg each) jump together off a 4 m high platform. how much would theEarth " recoil" or move? What energy would be imparted to the Earthby the impact? A 7.0 magnitude earthquake releases about 2x10^15J.Is your friend'sclaim reasonable? (one person pointed out the jumpers would need to jump with their knees locked and major resultwould be a very loud cry of pain on impact.)