Question

The pulley arrangements shown in the figure are identical, the mass of the rope being negligible. In case $\left(a\right)$ mass $m$ is lifted by attaching a mass of $2m$ to the other end of the rope. In case $\left(b\right)$ the mass $m$ is lifted by pulling the other end of the rope with a constant downward force $F=2mg$ , where $g$ is the acceleration due to gravity. The acceleration of mass $m$ in case $\left(a\right)$ is :-

• A. zero
• B. More than that in case $\left(b\right)$
• C. Less than that in case $\left(b\right)$
• D. Equal to that in case $\left(b\right)$

Answer 1

Answer: (C)

Case $\left(a\right)$ : $a_{1}=\frac{2 mg - mg}{3 m}=\frac{g}{3}$
Case $\left(b\right)$ : $a_{2}=\frac{2 mg - mg}{m}=g$