A thin uniform rod, pivoted at O, is rotating in the horizontal plane with constatn angular speed `omega`, as shown in the figure. At time t = 0, a small insect starts from O and moves with constant sped v, with respect to the rod towards the other end. It reaches the end of the rod at t =T and stops. The angular speed of the system remains `omega` throughout. The magnitude of the torque `(|vecpi|)` about O, as a function of time is best represented by which plot?

Options

A.
B.
C.
D.

Answer

B

Explanation

`tau=omega(dI)/(dt)=omegad/(dt) (mv^(2)t^(2))=omega^(2)t=momegav^(2)t` (`:'I=ml^(2) -mv^(2)r^(2))`