Question

A 3000 kg elevator rises from rest in the basement to the floor. A distance of 25m . As it passes the fourth floor it's speed is 3 m/s . There's a constant frictional force of 500N. Calculate the work by the lifting mechanism?

Answer 1

Explanation and Calculation.

• The minimum needed energy or the minimum work need to be done to lift upto 25 m is,

$\qquad\qquad \begin{aligned} \small E&=\small mgh+fh\\ &=\small 25\,(3000\times9.8+500)\\ &=\small 29900\,J \end{aligned}$