A helicopter lifts a body of mass `100kg` to a height of `500m` at a constant speed. It takes `5min` to lift the body. Find the work done by the helicopter and the power required.

Explanation

The helicopter does work. When the helicopter raises the mass, the potential energy of the body changes. Potential energy gained by the mass `=mgh=1000xx9.8xx500=4900kJ`
Work done by the helicopter=Gain in potential energy by the body=`4900kJ`. Power is developed with respect to the ground. Power developed=work done by the helicopter/time taken to do the work `=4900kJ//5xx60=16.333kW`
We assign a positive sign for the power developed as the helicopter serves as the source for delivering the power.