A block and tackle system consisting of 5pulleys are used to raise a load of 400N through a height of 10m, if the work done against friction is 100joules.

1.calculate the work done by effort.
2.Calculate the efficiency of the system.

work output = 400 Newtons * 10 meters = 4,000 Joules

work input = 4,000 + 100 = 4,100 Joules
efficiency = 100 (4000/4100) = 97.6%