(2007? Panzhihua simulation) as shown in the figure, a long wooden board is placed on the horizontal ground, and under the action of constant force F, it makes a uniform acceleration movement with an

(2007? Panzhihua simulation) as shown in the figure, a long wooden board is placed on the horizontal ground, and under the action of constant force F, it makes a uniform acceleration movement with an acceleration of A to the left, while A. according to the stress analysis of a, a remains static. A is pulled by the spring in the horizontal direction and the sliding friction of the wooden board against A, so the sliding friction of the wooden block is T, so A is wrong.

The stress analysis of B and A shows that A remains stationary. A is subjected to the tension of spring and the sliding friction of wood against A in the horizontal direction. According to the equilibrium condition, the sliding friction of block A is equal to the tension of spring T, so B is correct.

C. If the force of 2F acts on the long board, the board will accelerate, but the sliding friction of block A remains unchanged, which is still equal to t, regardless of f, so c is correct.

D, if the long wooden board is uniformly accelerated with the acceleration of 2a, the dynamic friction coefficient between them is unchanged, and the pressure of A on the wooden board is unchanged, then the sliding friction on the wooden block A remains unchanged, which is still equal to T, so D is wrong.

So: BC.