Chapter 7, Problem 7Q

According to Eq. 7-4, the longer the impact time of an impulse, the smaller the force can be for the same momentum change, and hence the smaller the deformation of the object on which the force acts. On this basis, explain the value of air bags, which are intended to inflate during an automobile collision and reduce the possibility of fracture or death.

$\stackrel{\to }{F}\Delta t=\Delta \stackrel{\to }{p}$

The quantity on the left, the product of the force times the time $\Delta t$ over which the force acts, is called the impulse: