A 75kg stunt performer jumps from rest off a platform 5.0m above the upper surface of a large safety airbag. Upon landing, the performer depresses the airbag and comes to rest in 0.40s. Neglect air resistance while the performer is in free fall and assume that the upward normal force exerted by the airbag on the performer is approximately constant during the deceleration interval.
(a) Calculate the performer’s speed just before first making contact with the airbag.
(b) Determine the change in the performer’s vertical momentum from the instant just before contact to the instant the performer comes to rest.
(c) Calculate the magnitude of the average upward force exerted on the performer by the airbag while the performer is slowing to rest.
(d) Express the average force found in part (c) as a multiple of the performer’s weight mg. Interpret this ratio in terms of the potential for injury reduction supplied by the airbag.