A boxer stops a punch with his head. To approximate the force of the blow, treat the opponent's glove, hand, and forearm as a particle of mass 1.49 kg moving with an initial velocity of 19.5 m/s.
a) Estimate the force exerted on the head if the hand moves forward 11.9 cm while delivering the blow and then coming to rest.
b) Estimate the force exerted on the head if the head is deliberately moved back during the punch so that the hand moves forward 23.8 cm while decelerating.