Question

Two equations of two S.H.M. are $x = a\sin(\omega t - \alpha)$ and $y = b\cos(\omega t - \alpha)$. The phase difference between the two is

• A. 0⁰
• B. α⁰
• C. 90⁰
• D. 180⁰

Answer 1

Answer: (C)

90⁰

Answer 2

$x = a\sin(\omega t - \alpha)$

and $y = b\cos(\omega t - \alpha)$ =$b\sin(\omega t - \alpha + \pi/2)$

Now the phase difference = $(\omega t - \alpha + \frac{\pi}{2}) - (\omega t - \alpha) = \pi/2 = 90^{o}$

$\Delta T = 12 \times 10^{- 5} \times 86400sec/\text{day}$ = 10.3 sec/day.