Answer:
The work done by the person to raise a load of 300kg through a height of 4m is 3000J
Explanation:
Calculate the work done by the person:
Given efficiency of the machine = 80%
Mass of the load, m = 300kg
Height raised, h = 4m
Acceleration due to gravity, g = 10m/s^2
Calculate the work done by the machine:
Work done by the machine = Work output / Work input
Work output = mgh = 300kg * 10m/s^2 * 4m = 12000J
Work input = Work output / Efficiency = 12000J / 0.80 = 15000J
Calculate the work done by the person:
Work done by the person = Work input - Work output = 15000J - 12000J = 3000J
