Physics - SHM Question with Solution | TestHub

Comparing the given equation $y=A\sin \left(\pi t+\varphi \right)$ with a standard equation $y=A\sin \left(\omega t+\varphi \right)$. We have

$\omega =\pi \mathrm{rad} {\mathrm{s}}^{-1}$

Since time period is  $T=\frac{2\pi }{\omega }=2 \mathrm{s}$, it is a second's pendulum.

$T=2\pi \sqrt{\frac{L}{g}}\Rightarrow L=\frac{g}{{\pi }^2}=99.4 \mathrm{cm}$