Question

A block of mass M is being pulled along rough horizontal surface. The coefficient of friction between the block and the surface is $\mu$. If another block of mass M/2 is placed on the block and it is again pulled on the surface, the coefficient of friction between the block and the surface will be

• A. $\mu$
• B. $\frac{3\mu }{2}$
• C. $2\mu$
• D. $\frac{5\mu }{2}$

Answer 1

The correct option is A $\mu$

coefficient of friction. A measure of the amount of resistance that a surface exerts on or substances moving over it, equal to the ratio between the maximal frictional force that the surface exerts and the force pushing the object toward the surface.

coefficient of friction does not change when we increase normal force .

Hence the correct option is A.