Question

A disc is freely rotating with an angular speed co on a smooth horizontal plane. It is hooked at a rigid peg P and rotates about P without bouncing. Its angular speed after the impact will be equal to:

• A. $\omega$
• B. $\frac{\omega }{3}$
• C. $\frac{\omega }{2}$
• D. None of these

Answer 1

The correct option is B $\frac{\omega }{3}$

Angular momentum is conserb in both case

$I_{1}w=I_2{w}_2$

$\frac{{MR}^2}{2}w={MR}^2{w}_2$

$w_2=\frac{w}{3}$ Option - C