Two riders, A and B, of equal mass, are riding identical bicycles. Rider A posit

Question

Two riders, A and B, of equal mass, are riding identical bicycles. Rider A positions the chain of his bicycle on a smaller rear sprocket than does Rider B. Both riders travel the exact same distance d at the exact same speed v along a level road (assume no friction). Which of the following is true?

A) Rider A performs less work on the pedals than Rider B

B) Neither Rider A nor Rider B perform any work on the pedals.

C) Rider A performs more work on the pedals than Rider B

D) Riders A and B perform equal amounts of work on the pedals.

Explanation / Answer

since both travell same distance in same time,
angular speed w is same.
moment of inertia, I= m*r^2
So i will be less if r is less
work done = increase in kinetic energy = 0.5*i*w^2
so, lesser r imples less work done
Rider A performs less work on the pedals than Rider B

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