${V_{1}^{2}=\omega^{2}\left(a^{2}-x_{1}^{2}\right)}...(i)$
${V_{2}^{2}=\omega^{2}\left(a^{2}-x_{2}^{2}\right)}...(ii)$
From equations $(i)$ and $(ii),$ we get
$V_{1}^{2}-V_{2}^{2}=\omega^{2}\left(x_{2}^{2}-x_{1}^{2}\right)$
$\omega=\sqrt{\frac{V_{1}^{2}-V_{2}^{2}}{x_{2}^{2}-x_{1}^{2}}} $
$T=2 \pi \sqrt{\frac{x_{2}^{2}-x_{1}^{2}}{V_{1}^{2}-V_{2}^{2}}}$

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 $g =10 \ m / s ^2$ )


