$\Rightarrow \mathrm{A}=\frac{1}{2 \pi \mathrm{f}} \sqrt{\frac{2 \mathrm{E}}{\mathrm{m}}}$
Putting $\mathrm{E}=\mathrm{K}+\mathrm{U}$ we obtain,
$A=\frac{1}{2 \pi\left(\frac{25}{\pi}\right)} \sqrt{\frac{2 \times(0.5+0.4)}{0.2}} \Rightarrow A=0.06$

| $A (mm \,\,s^{-2}$) |
$16$ |
$8$ |
$0$ |
$- 8$ |
$- 16$ |
|
$x\;(mm)$ |
$- 4$ |
$- 2$ |
$0$ |
$2$ |
$4$ |


