As shown in figure, a block of mass m is projected from wall A with...

As shown in figure, a block of mass $m$ is projected from wall A with velocity $2 \mathrm{v}_0$ on the rough surface with constant sliding friction to hit the wall B with velocity $\mathrm{v}_0$. With what velocity same mass $m$ should be projected to hit the wall B with same velocity $\mathrm{v}_0$ if the surface is now moving upward with an acceleration of $\mathrm{a}=4 \mathrm{~g}$ ?