Question

A boy is moving on a straight road against a frictional force of 5 N. After travelling a distance of 1.5 km, he forgets the correct path at a round about (see figure.) 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 $(\pi =3.14)$.

• A. 18500 J
• B. 17500 J
• C. 18000 J
• D. 22210 J

Answer 1

The correct option is D 22210 J

Because,frictional force is non-conservative force so the total travelling distance$=1500m+2000m+(1.5\times 2\times 3.14\times 100)=4442m$
frictional force$=5N$
so,the work done$=F.S=5\times 4442=22210J.$