A construction crane lifted bags of dry cement with a total weight of 500 kg to a height of 20 meters.

A construction crane lifted bags of dry cement with a total weight of 500 kg to a height of 20 meters. Identify the work that the crane did.

Given:

m = 500 kilograms – the mass of bags of dry cement, which was lifted by a construction crane;

h = 20 meters – the height to which the cement bags were lifted.

It is required to determine A (Joule) – the work performed by the construction crane.

Since it was not specified in the problem statement, we believe that the crane lifted the bags evenly. Then, the force applied by the crane will be equal to the force of gravity acting on the bags:

F = F gravity = m * g, where g = 9.8 Newton / kilogram;

F = 500 * 9.8 = 4900 Newton.

Then the perfect work will be equal to:

A = F * h = 4900 * 20 = 98000 Joules = 98 kJ.

Answer: when lifting the bags, the construction crane performed a work equal to 98 kJ.