Question

Two masses m and M are lying on a surface moving with acceleration a. Only the given supporting and moving surface has coefficient of friction as μ. The frictional forces for μ>a/gand μ<a/gare

• A. ma, ma
• B. ma, μmg
• C. μmg, μmg
• D. μmg, ma

Answer 1

Answer: (B)

ma, μmg

Answer 2

The maximum force of friction,

f_max = μmg

or a_max = $\frac{f_{\max}}{m}$

or m = $\frac{a_{\max}}{g}$.

Taking a less than a_max, friction f is also less than f_max. Here, if the value of μ > a/g then f ≠ μ mg rather f = ma.