Question

In the arrangement shown in the figure mass of the block A and body B are 2m, 8m respectively. The surface between body B and floor is smooth. The body B is connected to block C by means of pulley. If the whole system is released then the minimum value of mass of the block C so that the block A remains stationary with respect to B is (Coefficients of friction between A and B is $\mu$)

• A. $\frac{m}{\mu }$
• B. $\frac{2m}{\mu +1}$
• C. $\frac{10m}{\mu }$
• D. $\frac{10m}{\mu -1}$

Answer 1

The correct option is D $\frac{10m}{\mu -1}$

$a=\frac{m^{\prime }g}{2m+8m+m^{\prime }}=\frac{g}{\mu }$
$m^{\prime }=\frac{10m}{\mu -1}$