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

683.79J

Explanation:

Be careful with that bag !!

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

Hence the work done is:

(21×9.8+91.5)N×2.3m=683.79J