Average Force?

Question

In a car crash, a 50 kg passenger moving at 15 m/s is stopped by an air bag in 0.10 sec. What is the average force the air bag exerts on the passenger?

 

Show work or explain concept using physics terms please. 

Answer 1

Change in momentum of the passenger:

mΔv = 50kg * (0 - 15m/s) = -750 kg*m/s

 

Impulse by the air bag:

I = F*t = F*0.1s

 

Since the impulse from the air bag directly translates to the change in momentum of the passenger:

0.1F = -750 kg*m/s

=>F = -7500 Newtons. (The negative sign because the impulse opposes the passenger velocity)