Two inclined planes are placed as shown in figure. A block is projected from the Point A of inclined plane AB along its surface with a velocity just…

Two inclined planes are placed as shown in figure. A block is projected from the Point A of inclined plane AB along its surface with a velocity just sufficient to carry it to the top Point B at a height $\displaystyle 10$ m. After reaching the Point B the block slides down on inclined plane BC . Time it takes to reach to the point C from point A is $\displaystyle \mathrm{t}(\sqrt{2}+1) \mathrm{s}$. The value of t is \_\_\_\_. (use $\displaystyle \mathrm{g}=10 \mathrm{~m} / \mathrm{s}^2$ )