You are analyzing a scenario where two blocks are placed on a surface, Block A has a mass of 5 kg and Block B has a mass of 0.4 kg. Both blocks experience different frictional forces against the same surface. Classify the following statements into correct categories regarding their friction coefficients: 1) The friction coefficient of Block A is greater than that of Block B. 2) The frictional force on Block B can be considered negligible compared to Block A. 3) The friction coefficient depends solely on the mass of the block. 4) The surface material affects the friction coefficient regardless of mass. Which statements belong to the category of 'Correct Understanding of Friction Coefficients'?

The only statement that reflects a correct understanding of friction coefficients is statement 4: the coefficient depends on the surface material, not on the mass of the block. Statements 1, 2, and 3 are incorrect because a coefficient does not increase with mass, frictional force differences do not directly determine the coefficient, and mass alone does not dictate the coefficient. Thus, only statement 4 belongs to the correct category.