Problem 1: A particle of mass m is displaced from a position P1 to P2 with position vectors and by a force . Find the work done by the force.
Solution: If the displacement of the particle is , the work done W by the given force is equal to W = F→.S→ , when F→ is a constant force.
W = F→.S→ …(1)
Using (1), (2) and (3)
Þ W = (c-a)b + (a-b)c + (b-c)a
Þ W = bc – ab + ac – bc + ab – ac = 0
Net work done by the force for the given displacement is zero.