A block of mass $\mathrm{M}=2\mathrm{ }\mathrm{k}\mathrm{g}$ with a semicircular track of radius $\mathrm{R}=1.1\mathrm{ }\mathrm{m}$ rests on a horizontal frictionless surface. A uniform cylinder of radius $\mathrm{r}=10\mathrm{ }\mathrm{c}\mathrm{m}$ and mass $\mathrm{m}=1.0\mathrm{ }\mathrm{k}\mathrm{g}$ is released from rest from the top point $\mathrm{A}$. The cylinder slips on the semicircular frictionless track. The speed of the block when the cylinder reaches the bottom of the track at $\mathrm{B}$ is $\left(\mathrm{g}=10 \mathrm{m} {\mathrm{s}}^{-2}\right)$