This question is an exact duplicate of:
An elevator does need some kind of acceleration when it starts to rise up so there has to be s force acting on it. But it surely does not accelerate the whole time so after some distance or time it reaches a speed and stops to accelerate. In an old physics textbook I found an example where the power a motor would need to lift it was calculated like this
P = F * v
But they did not take the average speed for v but the speed which would be reached at the end of the acceleration. Why was this speed used and not the average speed?