For slipping $\begin{aligned}& \mathrm{a}=\mathrm{g} \sin \theta \
& \ell=\frac{1}{2} \mathrm{at}^2 \Rightarrow \mathrm{t}=\sqrt{\frac{2 \ell}{\mathrm{g} \sin \theta}}\end{aligned}Forrolling\begin{aligned}& \mathrm{a}^{\prime}=\frac{\mathrm{g} \sin \theta}{1+\frac{\mathrm{k}^2}{\mathrm{R}^2}}\left[\mathrm{k}=\frac{\mathrm{R}}{\sqrt{2}}\right] \& \Rightarrow \mathrm{a}^{\prime}=\frac{2 \mathrm{g} \sin \theta}{3} \& \ell=\frac{1}{2} \mathrm{a}^{\prime}\left(\mathrm{t}^{\prime}\right)^2 \& \Rightarrow \mathrm{t}^{\prime}=\sqrt{\frac{6 \ell}{2 \mathrm{g} \sin \theta}}=\sqrt{\frac{\alpha}{2}} \sqrt{\frac{2 \ell}{\mathrm{g} \sin \theta}} \
& \Rightarrow \alpha=3\end{aligned}$