Waves

The equation of wave is given by \(\mathrm{y}=10 \sin \left(\frac{2 \pi \mathrm{t}}{30}+\alpha\right)\). If the displacement is \(5 \mathrm{~cm}\) at \(\mathrm{t}=0\), then the total phase at \(\mathrm{t}=7.5 \mathrm{~s}\) will be

\(\left[\sin 30^{\circ}=\cos 60^{\circ}=\frac{1}{2}, \cos 30^{\circ}=\sin 60^{\circ}=\frac{\sqrt{3}}{2}\right]\)