momrnt of Inertia \((I)\) of cubical block is given by

\(\begin{array}{l}
I = m\left( {\frac{{{R^2}}}{6} + {{\left( {\frac{R}{{\sqrt 2 }}} \right)}^2}} \right)\\
\therefore \,\,\omega  = \frac{{m.2\frac{R}{2}}}{{m\left( {\frac{{{R^2}}}{6} + {{\left( {\frac{R}{{\sqrt 2 }}} \right)}^2}} \right)}}\\
 \Rightarrow \omega  = \frac{{12}}{{8R}} = \frac{3}{{2 \times 0.3}} = \frac{{10}}{2} = 5\,rad/s.
\end{array}\)