Question

Find the minimum value of coefficient of friction between the $6kg$ block and the surface if the system shown does not accelerate.

• A. $\mu =\frac{5}{6}$
• B. $\mu =\frac{2}{3}$
• C. $\mu =\frac{1}{2}$
• D. $\mu =\frac{3}{4}$

Answer 1

The correct option is A $\mu =\frac{5}{6}$

The given system can be reframed as

Let the coefficient of friction be $\mu$
So, from the given figure we can write the force equations for the condition i.e. system has zero acceleration as
$\left(a\right)T=5g$
$\left(b\right)T=f=\mu \times N=\mu \left(6g\right)$
Hence, from above two equations we get
$\mu \left(6g\right)=5g$
$\Rightarrow \mu =\frac{5}{6}$