$x(t=1 s)=A \sin \left(\frac{2 \pi}{T} t\right)=A \sin \left(\frac{2 \pi}{8}\right)=A \sin \left(\frac{\pi}{4}\right)=\frac{A}{\sqrt{2}}$
$x(t=2 s)=A \sin \left(\frac{2 \pi}{T} t\right)=A \sin \left(\frac{2 \pi}{8} \times 2\right)=A \sin \left(\frac{\pi}{2}\right)=A$
And the required ratio is$:$
$\frac{x(t=1 s)}{x(t=2 s)-x(t=1 s)}=\frac{\frac{A}{\sqrt{2}}}{A-\frac{A}{\sqrt{2}}}=\frac{1}{\sqrt{2}-1}=\sqrt{2}+1$
Simultaneously at $t=0$, a small pebble is projected with speed $v$ from point $P$ at an angle of $45^{\circ}$ as shown in the figure. Point $P$ is at a horizontal distance of $10 \ cm$ from $O$. If the pebble hits the block at $t=1 \ s$, the value of $v$ is (take $g =10 \ m / s ^2$ )

