Question

Block $A$ of mass $2m$ is hanging from a vertical massless spring of spring constant $k$ and is at rest. Another block $B$ of mass $m$ strikes the block $A$ with velocity $u$ and sticks to it as shown. The magnitude of the acceleration of the combined system of blocks just after collision is :

• A. $\frac{g}{2}$
• B. $\frac{g}{3}$
• C. $g$
• D. Zero

Answer 1

Answer: (B)

$a=\frac{3mg-2mg}{3m}=\frac{g}{3}$