Question

Find minimum value of $\mu$ for which it remains at rest.

Answer 1

block $2m$ is not involed in any type of motion, it wil remain unmoved . so for no slipping block m should also be at rest

consider block m,

net force on it should be zero,

$T-\mu mg=0$

$T=F$ ,so

$\mu =\frac{F}{mg}$ , it will be its min. value (a)