Question

1) In a car collision, the driver's body must change speed from a high value to zero. This is true whether or not an airbag is used, so why use an airbag? How does it reduce injuries? Answer needs to include a discussion of impulse (force and time).

2) Two playground balls, the type used in the game of dodge ball, are inflated to different levels. One is fully inflated and the other is flat. Neglecting air resistance, which one would you rather be hit with? Why? Include both force and duration.

Answer 1

1) Airbags reduce the IMPULSE during a collision. When there is a collision, high amount of force is applied during a short duration of time and thus high impulse will be acted upon. Airbags in this case increase the duration of time which in turn reduces the impulse and thus injuries.

2) If I was to get hit with any of the balls I prefer the ball which is flat because the inflated ball bounces back as soon as it hits whereas the other ball does not. And the impulse which acts is higher in case of the inflated ball as the duration of time is much less (force acting in less duration of time) compared to that of the flat ball (force acting in more duration of time).