$\therefore \quad A=\frac{g}{\omega^{2}}=\frac{g}{\left(\frac{2 \pi}{T}\right)^{2}}=\frac{g T^{2}}{4 \pi^{2}}$
$\mathrm{A}=\frac{10 \times 4}{4 \pi^{2}}=\frac{10}{\pi^{2}} \mathrm{m}$
${y_1} = 8\,\cos\, \omega t;\,{y_2} = 4\,\cos \,\left( {\omega t + \frac{\pi }{2}} \right)$ ;
${y_3} = 2\cos \,\left( {\omega t + \pi } \right);\,{y_4} = \,\cos \,\left( {\omega t + \frac{{3\pi }}{2}} \right)$ ,
are superposed on each other. The resulting amplitude and phase are respectively;