$\left\{ \begin{array}{l}{t_1}:{\rm{ }}x_1^2 + \frac{{v_1^2}}{{{\omega ^2}}} = {A^2}\left( 1 \right)\\{t_2}:{\rm{ }}x_2^2 + \frac{{v_2^2}}{{{\omega ^2}}} = {A^2}\left( 2 \right)\end{array} \right. \Rightarrow {\rm{ }}x_1^2 + \frac{{v_1^2}}{{{\omega ^2}}} = x_2^2 + \frac{{v_2^2}}{{{\omega ^2}}} \Rightarrow \omega = \sqrt {\frac{{v_1^2 – v_2^2}}{{x_2^2 – x_1^2}}} = 2,5\left( {ra{\rm{d/s}}} \right)$ $\left( 1 \right)+\left( 2 \right)\to {{A}^{2}}=\frac{x_{1}^{2}+\frac{v_{1}^{2}}{{{\omega }^{2}}}+x_{2}^{2}+\frac{v_{2}^{2}}{{{\omega }^{2}}}}{2}=\frac{v_{1}^{2}x_{2}^{2}-v_{2}^{2}x_{1}^{2}}{v_{1}^{2}-v_{2}^{2}}\Rightarrow A=16\left( cm \right)$ → vmax = Aω = 40 cm/s.