As shown in the figure, in the experiment of studying friction, a small wooden block placed on the horizontal table is pulled horizontally with a spring scale each time, and the reading of the small wooden block's movement is shown in the following table (the contact surface between the wooden block and the table is the same each time): then from the table, we can see () & nbsp; the number of experiments, the movement state of the small wooden block, and the reading of the spring scale (n) 1 static 0.4 2 static 0.6 3 Acceleration 0.7 4 constant speed 0.5 5 deceleration 0.3 A. The maximum friction force on the block is 0.7nb. The maximum static friction force on the block may be 0.5nc. In the five experiments, the friction force on the block is the same three times. D. in the five experiments, the friction force on the block is the same two times

As shown in the figure, in the experiment of studying friction, a small wooden block placed on the horizontal table is pulled horizontally with a spring scale each time, and the reading of the small wooden block's movement is shown in the following table (the contact surface between the wooden block and the table is the same each time): then from the table, we can see () & nbsp; the number of experiments, the movement state of the small wooden block, and the reading of the spring scale (n) 1 static 0.4 2 static 0.6 3 Acceleration 0.7 4 constant speed 0.5 5 deceleration 0.3 A. The maximum friction force on the block is 0.7nb. The maximum static friction force on the block may be 0.5nc. In the five experiments, the friction force on the block is the same three times. D. in the five experiments, the friction force on the block is the same two times

A. When the pulling force is 0.7n, it has accelerated, so it is not the maximum friction force. So a error B, when the pulling force is 0.6N, the block is still static, so the maximum static friction force must be greater than or equal to 0.6N. So B error C, whether accelerating or decelerating, the friction force in this problem is equal, so C is correct. D is wrong, so C is selected