Question

The accelerations of the blocks A and B in the situation shown in the figure are:

• A. $\frac{g}{7},\frac{g}{7}$
• B. $\frac{2g}{7},\frac{g}{7}$
• C. $\frac{2g}{7},\frac{2g}{7}$
• D. None

Answer 1

Answer: (B)

$\frac{2g}{7},\frac{g}{7}$

From FBD,

Lets $a$ be the acceleration.

For $5kg$ block , $5a=2T-50....\left(1\right)$
For $4kg$ block, $4\left(2a\right)=40-T....\left(2\right)$
Solving (1),(2), $5a=2(40-8a)-50$
or,$21a=30\Rightarrow a=\frac{30}{21}=\frac{10}{7}=\frac{g}{7}$
Acceleration of block A $=2a=\frac{2g}{7}$
Acceleration of block B $=a=\frac{g}{7}$