Question

A uniform rod of mass $'m'$ and length $'l'$ lying on a smooth horizontal table is pivoted about one end. An impulse $'J'$ is applied to the other end. Angular speed with which rod starts rotating is

• A. $\frac{3 J}{m l}$
• B. $\frac{3 J l}{m}$
• C. $\frac{2 J}{m l}$
• D. $\frac{2 J l}{m}$

Answer 1

Answer: (A)

Angular impulse $=I\left(w_{2} - w_{1}\right)$
$\Rightarrow J\times l=\frac{m l^{2}}{3}\left(w - 0\right)\Rightarrow w=\frac{3 J}{m l}$