If displacement $s=5 \sin (2 t)$, then the velocity at the end of $\frac{\pi}{3} \mathrm{~s}$ is
If displacement $s=5 \sin (2 t)$, then the velocity at the end of $\frac{\pi}{3} \mathrm{~s}$ is
- 5
- $-5 \sqrt{3}$
- $5 \sqrt{3}$
- –5
Solution
$s=5 \sin (2 t)$
differentiate w.r.t. ' $t$ '
$
\begin{aligned}
& \frac{d s}{d t}=5 \cdot \frac{d}{d t} \sin (2 t) \\
& \frac{d s}{d t}=5 \cdot \cos (2 t) \cdot 2=10 \cdot \cos 2 t
\end{aligned}
$
Velocity when $t=\frac{\pi}{3} \sec =\left.\frac{d s}{d t}\right|_{t=\pi / 3}=10 \cdot \cos 2\left(\frac{\pi}{3}\right)$
$
=10 \times-\frac{1}{2}=-5
$
Hence, option (4) is correct
Asked in: AP EAMCET 2020 (22 Sep Shift 2)
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