Question

In the pulley arrangement shown, the pulley $P_2$ is movable. Assuming coefficient of friction between m and surface to be $\mu$, the minimum value of M for which m is at rest is

• A. $M=\frac{\mu M}{2}$
• B. $m=\frac{\mu M}{2}$
• C. $M=\frac{m}{2\mu }$
• D. $m=\frac{M}{2\mu }$

Answer 1

Answer: (A)

$f=2T.....(i)$

and $T=Mg.....(ii)$

If m be at rest friction will be static

$f\le \mu N$

$2Mg\le \mu mg$

$\Rightarrow M=\frac{\mu g}{2}$