Question

The angular velocity of second's hand of a watch will be

• A. $\frac{\pi }{\text{60}}\text{ rad s}^{- 1}$
• B. $\frac{\pi }{\text{30}}\text{ rad s}^{- 1}$
• C. $\text{60}\pi \text{ rad s}^{- 1}$
• D. $\text{30}\pi \text{ rad s}^{- 1}$

Answer 1

Answer: (B)

The angular velocity is given by
$\omega =\frac{\Delta \theta }{\Delta t}$
Where $\Delta \theta $ is the angle made by the second's hand and $\Delta t$ is the time taken.
In one minute, $\Delta \theta =2\pi rad$ and $\Delta t=60s$
So, $\omega =\frac{2 \pi rad}{60 s}=\frac{\pi }{30}rads^{- 1}$