Question

Initially mass $m$ is held such that spring is in relaxed condition. If mass $m$ is suddenly released, maximum elongation in spring will be

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

Answer 1

Answer: (B)

$E_{i}=E_{f}$
$\Rightarrow 0=-m g x+\frac{1}{2} k x^{2}$
$x=\frac{2 m g}{k}$