A hammer of mass 1 kg strikes on the head of a nail with a velocity of 2 ms–1. It drives the nail 0.01 m into a wooden block. Find the force applied by the hammer and the time of impact.

a = Retardation of the nail For the nail, 0 = u2 - 2as F = Force applied by the hammer on the nail = Average resistance force applied by wood on the nail= ma = 1 x 200N = 200NNow, v = Final velocity of the hammer = 0, u = Initial velocity of the hammer = 2m/sV = u - at ⇒ 0 = 2 - 200.t ⇒ t = 10-2s.