Wave Mechanics Question 547

Question: A particle starts with S.H.M. from the mean position as shown in figure below. Its amplitude is A and its time period is T. At one time, its speed is half that of the maximum speed. What is the displacement at that time?

Options:

A) $ \frac{\sqrt{2}A}{3} $

B) $ \frac{\sqrt{3}A}{2} $

C) $ \frac{2A}{\sqrt{3}} $

D) $ \frac{3A}{\sqrt{2}} $

Show Answer

Answer:

Correct Answer: B

Solution:

[b] $ v=\omega {{[A^{2}-x^{2}]}^{1/2}}\Rightarrow x={{[ A^{2}-\frac{V^{2}}{{{\omega }^{2}}} ]}^{1/2}} $ Given that $ v=\frac{{v _{\max }}}{2}=\frac{A\omega }{2} $ . $ so,{{[ A^{2}-\frac{A^{2}{{\omega }^{2}}}{4{{\omega }^{2}}} ]}^{1/2}}=\frac{\sqrt{3}}{2}.A $