Question

In the arrangement shown in the figure mass of the block B and A are 2m and 8m respectively. Surface between B and floor is smooth. The block B is connected to block C by means of a pulley. If a 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 (Co-efficient of friction between A and B is µ)-

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

Answer 1

Answer: (D)

$\frac { 10 \mathrm {~m} } { ( \mu - 1 ) }$

Answer 2

$\begin{array} { l l } \\ \mathrm { N } = 8 \mathrm { ma } & \ldots ( 1 ) \\ 8 \mathrm { mg } - \mu \mathrm { N } = \mu 8 \mathrm { ma } & \ldots ( 2 ) \\ \& \mathrm {~m} _ { 1 } \mathrm {~g} = \left( 10 \mathrm {~m} + \mathrm { m } _ { 1 } \right) \mathrm { a } & \ldots ( 3 ) \end{array}$