A small box of mass m1 is sitting on a board of mass m2 and length L (gure 1). The board rests on a frictionless horizontal surface. The coefficient of static friction between the board and the box is us. The coefficient of kinetic friction between the board and the box is, as usual, less than us. Throughout the problem, use 9 for the magnitude of the free-fall acceleration. In the hints, use f for the magnitude of the friction force between the board and the box. Figure 1 of 1