An automobile of mass 1000 kg travelling at 72 km h strikes a crash cushion and comes…
PHYSICS · Subjective · AP · Physics 1: Algebra-based · Linear Momentum · Linear Momentum
Problem
An automobile of mass 1000 kg travelling at 72 km h−1 strikes a crash cushion and comes to rest.
(i) Calculate the change in linear momentum of the car.
(ii) If the car stops uniformly in 0.30 s, find the average horizontal force exerted on the car by the cushion.
(iii) Modern cushions increase the stopping time to 1.5 s. Determine the average force in this case.
(iv) Express the average forces obtained in parts (ii) and (iii) as multiples of the weight of the car and comment on the effectiveness of the improved cushion.