Consider two uniform discs of the same thickness and different...

Moment of inertia of disc is given by $I = \dfrac{{MR}^{2}}{2} = \dfrac{\left[ρ\left({\pi R}^{2}\right)t\right]{R}^{2}}{2}$

$I\alpha{R}^{4}$

$\dfrac{{I}_{2}}{{I}_{1}} = {\left(\dfrac{{R}_{2}}{{R}_{1}}\right)}^{4}$

$\dfrac{16}{1} = {\alpha}^{4}$

$\alpha = 2$