Question

A 10g block placed on a rough horizontal floor is being pulled by a constant force 50N. Coefficient of kinetic friction between the block and the floor is 0.4. Find work done by each individual force acting on the block over displacement of 5m?

Answer 1

Answer - First we'll see the forces acting on the block. It's weight (mg=100N) Normal reaction from the ground, force of kinetic friction (16N) and last the applied force (F=50N)

As we can see that all forces are constant therefore now

Work done by gravity i. e. weight of the block Wg=0 (me perpendicular to x) x=displacement

Similarly Work done by Normal reaction =0 (Normal is perpendicular to the x)

Work done by applied force WF = F. Hence this is the answer. Hope that it may help you!