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:

\( W= F × d \)

Applied force, F = 140 N

Displacement, d = 15 m

W= 140 × 15 = 2100 J

Hence, 2100 J of labour is finished in tilling the length of the sector.