Question

a pair of bullocks exerts a force 140N on a plough. the field being ploughed is 15 m long. how much work is done in ploughing the length of the field?

Answer 1

work done=force*displacement
here force =140N and displacement or distance is 15 m 
so,
140*15= 2100J
HENCE work done is 2100J

Answer 2

Given,

Force, F = 140 N

Distance, s = 15 m

Work done, W =?

W = F × s

= 140 × 15

= 2100 J