As shown in the figure, two identical wooden blocks are clamped by vertical wooden boards to keep static. If the mass of each block is m, the friction force between the two blocks is Please analyze in detail, thank you!

As shown in the figure, two identical wooden blocks are clamped by vertical wooden boards to keep static. If the mass of each block is m, the friction force between the two blocks is Please analyze in detail, thank you!

First of all, the friction force of the two sides of the board to the block is mg, a total of 2mg, which is balanced with the total weight of the two blocks. Then, it is analyzed separately that one of the blocks is balanced by the downward gravity mg and the upward friction force mg given by one side of the board. There is no friction force between the two blocks, so the two blocks in the system are balanced