Wave Mechanics Question 536

Question: Part of a simple harmonic motion is graphed in the figure, where y is the displacement from the mean position. The correct equation describing this S.H. M. is

Options:

A) $ y=4\cos (0.6t) $

B) $ y=2\sin ( \frac{10}{3}t+\frac{\pi }{2} ) $

C) $ y=4\sin ( \frac{10}{3}t+\frac{\pi }{2} ) $

D) $ y=2\cos ( \frac{10}{3}t+\frac{\pi }{2} ) $

Show Answer

Answer:

Correct Answer: B

Solution:

[b] From the figure, $ \frac{T}{2}=0.3\pi , $
$ \

Therefore T=0.6\pi ,and,{\phi _{0}}=-\frac{\pi }{2} $ Thus $ y=A,\sin (\omega t+{\phi _{0}})=2\sin ( \frac{2\pi }{0.6\pi }t+-\frac{\pi }{2} ) $

$ =2\sin ( \frac{10t}{3}-\frac{\pi }{2} ) $ .