question_answer

     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 of radius 100 m as shown in figure. However, he moves on the circular path for one and half cycle and then he moves forward upto 2 km. Calculate the work done by him.

Answer:

 Force applied on road by bpy, F = 5 N Displacement on the circular path =One cycle + Half cycle = 0 + Diameter of circular path = 200 m Total displacement, s=1.5 x 1000 + 200 + 2 x 1000      =1500 + 200 + 2000 + 3700 m  Work done = Fs = 5 x 3700 = 18500 J