Suppose a small piece weighs m and n pieces weigh nmg.
Firstly, the whole method is used to analyze: n pieces of wood are regarded as a whole, and the friction between them and the board is analyzed.
Through the force analysis, it can be concluded that the friction on both sides of the plate is nmg, and the friction on one side is nmg/2.
Isolation method: analyze the stress analysis of the first block from left to right.
Vertical downward gravity, upward friction between plates and blocks, and friction between the second block and the first block.
To be still: the first block must be satisfied, and the total force of these three forces is 0.
List relationships: nmg/2 > mg. So the second plate is needed to give the first plate a downward force.
This F=nmg/2 MINUS mg.
General differentiation is the standard answer, f=mg(n-2)/2.
Because the force is mutual, so the mutual friction between the first block and the second block is these.
Similarly, between n- 1 and n,