Physics - W.E.P. Question with Solution | TestHub

From the question, it can be understood that the total distance the ball falls is $(\mathrm{S}+\mathrm{h})$ The spring is compressed through a length $h$ $\therefore$ Loss of P.E. by the ball $=\mathrm{mg}(\mathrm{S}+\mathrm{h})$ Work done on the spring $=\frac{1}{2}{\mathrm{Kh}}^2$ Using law of conservation of energy, $\begin{array}{rl}& \frac{1}{2}{\mathrm{Kh}}^2=\mathrm{mg}(\mathrm{S}+\mathrm{h})\\ \therefore & \mathrm{K}=\frac{2\mathrm{mg}(\mathrm{S}+\mathrm{h})}{{\mathrm{h}}^2}\end{array}$