One mole of nickel (6.02 x 10- atoms) has a mass of 59 g, and its density is 8.9g/cm'. You have a bar of nickel 2.56 m long witha square cross section, 2.7 mm on a side. You hang the rod vertically and attach a 31 kg mass to the bottom, and you observe that the bar becomes 0.59 mm longer. Next you remove the 31 kg mass, place the rod horizontally, and strike one end with a hammer. How much time / will elapse before a microphone at the other end of the bar will detect a disturbance? (Assume a simple cubic lattice for nickel)