Required information

Problem $02\mathrm{.}114-$ Counterweight power in elevator

Consider a vertical elevator whose cabin has a total mass of $800$ kg when fully loaded and $150$ kg when empty. The

weight of the elevator cabin is partially balanced by a $440\mathrm{.}0-$kg counterweight that is connected to the top of the cabin by

cables that pass through a pulley located on top of the elevator well. Neglecting the weight of the cables, and assuming

the guide rails and the pulleys to be frictionless, answer the questions that follow.

Problem $02\mathrm{.}114.$b $-$ Friction in elevator pulleys

Determine the power required while the empty cabin is descending at a constant speed of $1\mathrm{.}2\frac{m}{s}.$ What would your answer be if a

friction force of $800$ N has developed between the cabin and the guide rails?

The power required while the empty cabin is descending is

$1\mathrm{.}76$ kW $.$

The total power needed is

kW $.$