Waves

The equation of the wave is \(\mathrm{Y}=10 \sin \left(\frac{2 \pi \mathrm{t}}{30}+\alpha\right)\) If the displacement is \(5 \mathrm{~cm}\) at \(\mathrm{t}=0\) then the total phase at \(\mathrm{t}=7.5 \mathrm{~s}\) will be \(\left(\sin 30^{\circ}=0.5\right)\)