Question

Find the velocity of block $B$ i.e. $v_B$ in the shown figure.

• A. $2v$, downward
• B. $2v$, upward
• C. $\frac{v}{3}$, upward
• D. $\frac{v}{2}$, upward

Answer 1

The correct option is D $\frac{v}{2}$, upward

Let the velocity of block $B$ be $v_B$ downward and taking downward positive we have

As we know that, the string's end attached to the fixed pulley will have zero velocity. So, considering the points $1$ to $4$ in the figure, we have
$2v+v_B+v_B-v=0$
$\Rightarrow 2v_B=-v\Rightarrow v_B=-\frac{v}{2}$
Hence, the velocity of block $B$ will be $\frac{v}{2}$, upward.