Chapter 5, Problem 12RQ

Which requires the greater impulse, stopping something dead in its tracks or stopping it and then reversing its direction?

To determine

Whether the stopping something dead in its track or stopping it and then reversing its direction requires the greater impulse.

Answer to Problem 12RQ

Something requires greater impulse to stop and reverse the direction than to stop dead in its track due to more time for the force to stop and reverse the direction.

Explanation of Solution

The impulse of a body is the effect of the force that acts for some duration on the body. It is also the same as the change in the momentum of the body. If the force acts for a small duration on the body, then the change in the momentum of the body will also be small. If the same force acts for more time, than the change in momentum becomes high.

The time necessary for stopping something dead in its track is less than the time that is necessary to stop it and reverse the direction. The time necessary to stop something and reverse its direction is more because the force acts for more duration, so it requires the greater impulse.

Conclusion:

Therefore, something requires greater impulse to stop and reverse the direction than to stop dead in its track due to more time for the force to stop and reverse the direction.