Question

Find the velocity of block $A$ in the shown figure.

• A. $10\text{m/s}$, rightward
• B. $15\text{m/s}$, leftward
• C. $10\text{m/s}$, leftward
• D. $20\text{m/s}$, rightward

Answer 1

The correct option is D $20\text{m/s}$, rightward

Let us assume that the block $A$ moves rightward with a velocity of $v$ and taking rightward positive we have

Now considering the different points starting from $1$ to $8$ as shown in the figure, we can have
$v_B-v-v+v_B+v_B-v-v+v_B=0$
$\Rightarrow 4v=4v_B\Rightarrow v=v_B=20\text{m/s}$
Hence, velocity of block $A$ is $20\text{m/s}$, rightward.