A block of mass m is moving on a rough horizontal surface where coefficient of friction between block and surface is $\mathrm{\mu }\mathrm{ }=\mathrm{ }0.5$ . At t = 0 block is moving with a velocity $\overrightarrow{\mathrm{v}}$ then a horizontal force F = 2t is applied on it in the direction of velocity. Here t represent time then the speed of block after the application of force