Question

A body of mass 6kg is under a force which causes displacement in it given by S = t²/4 metres where t is time. The work done by the force in 2 seconds is

A porter pushes a trunk on a railway platform which has a rough surface. He applies a force of 100 N over a distance of 10 m. Thereafter, He gets progressively tired and his applied force reduces linearly with distance to 50 N. The total distance through which the trunk has been moved is 20 m. Plot the force applied by the woman and the frictional force, which is 50 N versus displacement. Calculate the work done by the two forces over 20 m.