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 distance the rope must be pulled in order to lift the bag of nails?
Work done on the load = Work done by the effort.
Since work done = force x distance moved in direction of force we can write:
This is when the system is 100% efficient. Since it is 75% efficient we can write:
We need to find