• # question_answer A body of mass m dropped from a certain height strikes a light vertical fixed spring of stiffness k. The height of its fall before touching the spring if the maximum compression of the spring is equal to $\frac{3mg}{k}$ is: A) $\frac{KQ}{R}$ B) $\frac{KQ}{\ell }$ C) $\frac{KQ}{\sqrt{{{R}^{2}}+{{\ell }^{2}}}}$ D) $\frac{mg}{4K}$

[a] $mg\left( h+\frac{3mg}{K} \right)=\frac{1}{2}K{{\left( \frac{3mg}{K} \right)}^{2}}$