A block slides down a rough inclined plane of slope angle $\theta$ with constant velocity.  It is then projected up the same plane with an initial velocity v.  The distance travelled by the block up the plane before coming to rest is

when it is sliding down
f = mg sin $\mathrm{\theta }$ , net acceleration is zero as velocity is constant.
when it is projected up retardation
$$\begin{gathered} \mathrm{a}=\frac{\mathrm{f}+\mathrm{mgsin\theta }}{\mathrm{m}} \\ =\frac{\mathrm{mgsin\theta }+\mathrm{mgsin\theta }}{\mathrm{m}} \\ =2\mathrm{gsin\theta } \end{gathered}$$

From 3^rd equation of motion ${\mathrm{v}}^2-{\mathrm{u}}^2=2\mathrm{as}$
$$\begin{gathered} 0-{\mathrm{v}}^2=-2\mathrm{as} \\ {\mathrm{v}}^2=2.2\mathrm{gsin\theta }.\mathrm{s} \\ \mathrm{s}=\frac{{\mathrm{v}}^2}{4\mathrm{gsin\theta }} \end{gathered}$$