. Consider the shown arrangement. The coefficient of friction between the two blocks is 0.5. There is no friction between the 4 kg block and the horizon

Consider the shown arrangement. The coefficient of friction between the two blocks is 0.5. There is no friction between the 4 kg block and the horizontal surface. If a horizontal force of 12 N is applied on the 2 kg block as shown in the figure, the acceleration of the 4 kg block would be