I have a problem about average power that I am stuck on:(adsbygoogle = window.adsbygoogle || []).push({});

A 686 kg elevator starts from rest and moves upward for 3.10 s with constant acceleration until it reaches its cruising speed, 1.70 m/s.

a) What is the average power of the elevator during this period?

b) What is the average power during an upward cruise with constant speed?

I used (delta x) = (V+Vo)/2 x t to solve for delta X, and got 2.635 m. I used V=Vo+at to solve for acceleration, and got 0.55 m/s^2 (I also used delta V over delta t and got the same answer).

I know that power is Work/time, which is F(delta x)/(delta t). I used F=mg to find a force of 994.18 N, and plugged it into work = F(delta X) to get 320.705 J.

I tried dividing this by my time, 3.1s, and got 320.705, but the Webassign page told me I was not only wrong but was off by orders of magnitude. Any tips on what I'm doing wrong?

thanks for your time and patience!

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# Homework Help: Power/work problem

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