Question

The spring block system as shown in figure is in equilibrium. The string connecting blocks $A$ and $B$ is cut. The mass of all the three blocks is $m$ and spring constant of both the spring is $k$. The amplitude of resulting oscillation of block $A$ is:

• A. $\frac{m g}{k}$
• B. $\frac{2 m g}{k}$
• C. $\frac{3 m g}{k}$
• D. $\frac{4 m g}{k}$

Answer 1

Answer: (B)

Just after cutting the string extension in spring $=\frac{3 m g}{k}$ and extension in the spring when block is in mean position $=\frac{m g}{k}$

$\Rightarrow $ Amplitude of oscillation is given as
$A=\frac{3 m g}{k}-\frac{m g}{k}=\frac{2 m g}{k}$