Question

A rod AB of length L and mass M is free to move on a frictionless horizontal surface is moving with a velocity v as shown in fig. End B of rod AB strikes end of wall. Assuming elastic impact, angular velocity of rod AB just after impact is

• A.
• B.
• C.
• D. None of these

Answer 1

The correct option is B

$\text{L-conservation}\Rightarrow M{v}_{cm}\frac{M{L}^2}{12}\omega =\frac{MvL}{2}\Rightarrow v_{cm}+\frac{\omega L}{6}=v\text{P-conservation}\Rightarrow \frac{\omega L}{2}-v_{cm}=v\Rightarrow \omega (\frac{L}{2}+\frac{L}{6})=2v\therefore \omega =\frac{3v}{L}$