Brain injuries generally occur any time the brain\'s acceleration reaches 100 {\
ID: 2046792 • Letter: B
Question
Brain injuries generally occur any time the brain's acceleration reaches 100 { m g} for even a short time. Consider a car running into a solid barrier. With an airbag, the driver's head moves through a distance of 20 { m cm} while the airbag stops it. Without an airbag, the head continues forward until the seatbelt stops the torso, causing the head to stop in a distance of only 5.0 { m cm}.
Find the maximum speed with which the car can strike the barrier without causing brain injury, using an airbag .
Explanation / Answer
a=100g=981m/s2
Let v be the velocity before clash.
a=v2/2s
v=sqrt(2as)=sqrt(2*981*0.2)=19.81m/s