Q.
A smooth rod $OP$ is fixed vertically. A disc of mass $m$ and radius $R$ is rolling without slipping at the given instant on a rough horizontal surface as shown. Velocity of centre of mass $C$ of disc is $v_{0}$ . A rod $AB$ of length $L$ is connected with disc at $A$ , $R / 2$ distance vertically up from centre of disc with pin joint (about which it can rotate freely), other end of the rod is attached to a small smooth ring $B$ , which can move freely over rod $OP$ . At an instant rod $AB$ makes an angle $60^\circ $ with the vertical. The velocity of ring on the vertical rod at this instant is.

NTA AbhyasNTA Abhyas 2020System of Particles and Rotational Motion
Solution: