Question

Blocks 1 and 2 are connected by a light string that passes over a pulley with negligible mass and friction, as shown in the figure. Block 1 is on a table covered with two different materials, A and B. The two-block system is released from rest, and the speed of block 1 begins to increase. When block 1 reaches material B, its speed increases at a greater rate. Which of the following correctly compares the coefficient of kinetic friction m between block 1 and the two materials and describes the change in the magnitude of the net force on block 2 as block 1 slides from material A to material B?

Answer 1

When block 1 slides from material A to material B, its speed increases at a greater rate. The coefficient of kinetic friction between block 1 and material B is lower than the coefficient of kinetic friction between block 1 and material A. The change in the magnitude of the net force on block 2 will decrease as block 1 slides from material A to material B.

Step-by-step explanation:

When block 1 slides from material A to material B, its speed increases at a greater rate. This suggests that the coefficient of kinetic friction between block 1 and material B is lower than the coefficient of kinetic friction between block 1 and material A. In other words, the frictional force between block 1 and material B is smaller than the frictional force between block 1 and material A.

Therefore, the correct comparison for the coefficients of kinetic friction would be that the coefficient of kinetic friction between block 1 and material B is lesser than the coefficient of kinetic friction between block 1 and material A.

The change in the magnitude of the net force on block 2 while block 1 slides from material A to material B depends on the difference in the frictional forces acting on block 1. Since the frictional force on block 1 is smaller when it slides on material B, the net force on block 2 will also decrease.