
Time period is $12 \,s$ from diagram.
$\omega=\frac{2 \pi}{12}=\frac{\pi}{6}$
Amplitude $A=4$
Initial phase is determined by putting known values in the equation.
$2=4 \sin \left(\frac{\pi}{6} t+\phi\right)$
$\sin ^{-1} \frac{1}{2}=\phi[t=0]$
$\frac{\pi}{6}=\phi$
Hence equation is $x=\left(\frac{\pi}{6} t+\frac{\pi}{6}\right)$
$y = A{e^{ - \frac{{bt}}{{2m}}}}\sin (\omega 't + \phi )$
where the symbols have their usual meanings. If a $2\ kg$ mass $(m)$ is attached to a spring of force constant $(K)$ $1250\ N/m$ , the period of the oscillation is $\left( {\pi /12} \right)s$ . The damping constant $‘b’$ has the value. ..... $kg/s$
