Question

Consider the situation shown in figure (8-E8). Initially the spring is unstretched when the system is released from rest. Assuming no friction in the pulley, find the maximum elongation of the spring.

Figure

Answer 1

Mass of the body is m.
Let the elongation in the spring be x.



Applying the law of conservation of energy,

$$\begin{gathered} \frac{1}{2}k{x}^2=mgx \\ \Rightarrow x=2mg\mathit{/}k \end{gathered}$$