Calculate the work done.

The boy first moves a distance of 1.5 km against the force of friction.

 

Hence, work done to cover this distance is

 

W₁ = Fs = 5 × 1500 = 7500 J

 

Now, the boy moves along a circle of radius 100 m for one and a half cycle.

For one complete cycle, displacement is zero and hence the work done will be zero. Thus, the boy will do work for remaining half cycle only. That is,

 

W₂ = 5 × 3.14 × 100 = 1570 J

 

Finally the boy moves forward for 2 km.

Hence, work done is

 

W₃ = 5 × 2000 = 10000 J

 

Thus, the total work done by the boy is

 

W = W₁ + W₂ + W₃ = 7500 + 1570 + 10000 = 19,070 J