A drop hammer of mass 120 kg falls 2.5 m onto a pile of mass 250 kg and drives it 70 mm into the ground. Calculate:

a.The velocity with which the hammer strikes the pile (use the conservation of energy principle)

b.The velocity immediately after the impact(use the conservation of momentum principle,
assuming the hammer does not rebound on impact)

c. The average ground resistance (use work-energy method)

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