A pulley system with 75% efficiency is set up to lift a 21kg bag of nails. The bag is lifted to a height of 2.3m by a person pulling on the rope with a force of 91.5N. What is the work done on the bag of nails by the pulley?

1 Answer
Apr 18, 2016

#683.79 J #


Be careful with that bag !!

The person applies a total of #(Mg+91.5 N)# force. And the displacement is #2.3 m#.

Hence the work done is:

#(21xx9.8+91.5)Nxx2.3m = 683.79 J #