A force of 7 N acts on an object. The displacement is, say 8 m, in the direction of the force (Fig. 11.3). Let us take it that the force acts on the object through the displacement. What is the work done in this case?
Work is done whenever the given conditions are satisfied:
→ A force acts on the body.
→ There is a displacement of the body caused by the applied force along the direction of the applied force.
Write an expression for the work done when a force is acting on an object in the direction of its displacement.
When a force F displaces a body through a distance S in the direction of the applied force, then the work done W on the body is given by the expression:
Work done = Force × Displacement
W = F x s
1 J is the amount of work done by a force of 1 N on an object that displaces it through a distance of 1 m in the direction of the applied force.
A pair of bullocks exerts a force of 140 N on a plough. The field being ploughed is 15 m long. How much work is done in ploughing the length of the field?
Work done by the bullocks is given by the expression:
Work done = Force x Displacement
W= F x d
Applied force, F = 140 N
Displacement, d = 15 m
W= 140 x 15 = 2100 J
Hence, 2100 J of work is done in ploughing the length of the field.