A simple harmonic oscillation is represented by $x=A \cos \left(\omega t+\frac{\pi}{4}\right)$. Its speed is…

A simple harmonic oscillation is represented by $x=A \cos \left(\omega t+\frac{\pi}{4}\right)$. Its speed is maximum when $t$ equals
  1. $\frac{\pi}{2 \omega}$
  2. $\frac{\pi}{4 \omega}$
  3. $\frac{\pi}{\omega}$
  4. $\frac{2 \pi}{\omega}$

Solution

Given that, equation of a particle executing Simple harmonic motion is $ x=A \cos \left(\omega t+\frac{\pi}{4}\right) $ Now, velocity of particle, $v=\frac{d x}{d t}$ $ \begin{aligned} v & =\frac{d}{d t}\left[A \cos \left(\omega t+\frac{\pi}{4}\right)\right] \\ & =-A \omega \sin \left(\omega t+\frac{\pi}{4}\right) \end{aligned} $ $v$ is maximum when $\sin \left(\omega t+\frac{\pi}{4}\right)=1$ $ \begin{array}{rlrl} \sin \left(\omega t+\frac{\pi}{4}\right) & =\sin \frac{\pi}{2} \\ \Rightarrow \quad \omega t+\pi / 4 & =\pi / 2 \\ \Rightarrow & t & =\frac{\pi}{4 \omega} \end{array} $

Asked in: AP EAMCET 2021 (24 Aug Shift 1)

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