Question

prove that the work done by coolie is zero

Answer 1

Since the weight is kept on the head of the coolie, therefore the force acting is perpendicular to the earth's surface, and as we all know that work is not said to be done when force is acting perpendicular.

Answer 2

when Kohli carrying some load on his head motion horizontal platform in order to balance the load of his head he applies a force on the load and the four direction which is equal to its weight. His displacement is along the horizontal direction find the angle between weight on the Coolie and the displacement is 90° point there for work done by him is zero