${y_1} = 8\,\cos\, \omega t;\,{y_2} = 4\,\cos \,\left( {\omega t + \frac{\pi }{2}} \right)$ ;
${y_3} = 2\cos \,\left( {\omega t + \pi } \right);\,{y_4} = \,\cos \,\left( {\omega t + \frac{{3\pi }}{2}} \right)$ ,
are superposed on each other. The resulting amplitude and phase are respectively;

| $A (mm \,\,s^{-2}$) |
$16$ |
$8$ |
$0$ |
$- 8$ |
$- 16$ |
|
$x\;(mm)$ |
$- 4$ |
$- 2$ |
$0$ |
$2$ |
$4$ |
Then the values of $A$ (in $m$) and $T$ (in $sec$) are :
