A boy is moving on a straight road against a frictional force of 5 N. After travelling a distance of 1.5 km he forgot the correct path at a round about (Fig. 11.1) of radius 100 m. However, he moves on the circular path for one and half cycle and then he moves forward upto 2.0 km. Calculate the work done by him.


k = 5 N, frictional force


Displacement according to diagram is:



1.5 km + 200 + 2km = 1500 + 200+ 2000 = 3,700 Km.


W = F.S


W = 5 × 3700 = 18,500 J.


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