
Angular frequency of oscillation $(\omega)=\sqrt{\frac{\mathrm{k}_{\mathrm{eq}}}{\mathrm{m}}}$
$(\omega)=\sqrt{\frac{5 \mathrm{k}}{3 \mathrm{~m}}}$
Period of oscillation $(\tau)=\frac{2 \pi}{\omega}=2 \pi \sqrt{\frac{3 \mathrm{~m}}{5 \mathrm{k}}}$
$=\pi \sqrt{\frac{12 \mathrm{~m}}{5 \mathrm{k}}}$
$x = a\,\sin \,\left( {\omega t + \pi /6} \right)$
After the elapse of what fraction of the time period the velocity of the particle will be equal to half of its maximum velocity?

