By conservation of angular momentum about the hinge
\(\mathrm{m}\left(\frac{\mathrm{v}}{\sqrt{2}}\right)\left(\frac{\ell}{2}\right)=\left[\frac{4 \mathrm{m} \ell^{2}}{12}+\frac{\mathrm{m} \ell^{2}}{4}\right] \omega\)
On solving
\(\omega=\frac{3 \sqrt{2}}{7}\left(\frac{v}{l}\right)\)