Question 12
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. However, he moves on the circular path for one and a half cycle and then he moves forward up to 2.0 km. Calculate the work done by him.
Given,
Total displacement travelled by the boy = 1500 m +{1.5 (2π r)} + 2000 m = 1500 m + 942 m + 2000 = 4442 m
Because, frictional force is non-conservative force(path dependent ) so the total travelling displacement is equal to 4442 m.
Frictional force = 5 N
We know that,
Work done = Force × Displacement
W = F × D
=> Work done (W) = 5 × 4442
W = 22210 J = 22.21 KJ