AAMC FL 3, C/P Section Q7

[mariposas905]

---

Members do not see this ad.

For this question, how do we know to use 1000N and not 5000N? both are decelerating forces...and the 5000N specifically corresponds to the 40 m/s the question is referring to. Help please??

 

[AdaptPrep]

Hi, Mariposas905--

The question starts out by saying, "If no braking occurs". Therefore, the generator was not engaged (no 5000 N at 40 m/s was engaged) and no stationary surface was added to the wheels to decelerate. If no braking occurs, then we have no deceleration (constant velocity of 40 m/s). So we must look at the free body diagram: 1000 N of force due to rolling friction/internal friction must be balanced by the power needed to maintain constant velocity. So the power output must be 1000 N x 40 m/s.

I hope that helps.

Happy Studying!