Question

H . While you are driving , your car collides with a tree. If you were to collide with the steering wheel, you would not come to a stop instantly; your center of gravity would travel 0.0 1 m before you were brought to a stop. In this case, you would feel

16 ,000 N of force from th e steering wheel – enough to break many ribs. If the force on you were 800 N or less, you would end up badly bruised, but with no broken bones. How much distance would an airbag let you travel while coming to a stop , so that you felt a for ce of only 1000 N?

Answer 1

The magnitude of the work done by the steering wheel to stop you

The work done is -160J, because force by the steering wheel on you and your displacement are in opposite directions. If they would have been in the same direction the work done would be +160J.

By work energy theorem

The amount of kinetic energy you had before collision is 160J, after you hit the steering wheel your kinetic energy quickly (in 0.01s) reduced to zero.

Now, consider the airbag. The airbag must do -160J of work to bring you to rest.