A rope is wound around a hollow cylinder of mass 3 kg and radius 40 cm. What is the angular acceleration of…

The torque about centre is $\tau =I \alpha$, here $I$ is the moment of inertia and $\alpha$ is angular acceleration.

The formula of moment of inertia is $M{R}^2$.
$F\times R=M{R}^2\alpha$
$30\times 0.4=3\times {\left(0.4\right)}^2\alpha$
$12=3\times 0.16\alpha$
$400=16\alpha$
Thus, angular acceleration is $\alpha =25\mathrm{ rad}/{\mathrm{s}}^2$