Work, Energy, and Power — Physics STD 11 Science — Question

Let F_f be the force of friction in a surface. The work done to carry a mass m from a point A to another point B is, -F_f AB. In the return path B to A also, the work done is -F_f AB, since the F_f acts against the motion. The net work done is therefore, -2F_f (AB). Since friction is dependent on the nature of the surface it is dependent on path.