Question

The length of second's hand in a watch is $cm$. The change in velocity of its tip in seconds is:

• A. $0$
• B. $\frac{\pi }{30\sqrt{2}}cm/s$
• C. $\frac{\pi }{30}cm/s$
• D. $\frac{\pi \sqrt{2}}{30}cm/s$

Answer 1

The correct option is A $0$

Given,

Length of second hand, $L=12cm$

Constant angular velocity, $\omega =\frac{2\pi }{T}=\frac{2\pi }{60}$

Average velocity, $V=L\omega =12\times \frac{2\pi }{60}=\frac{4\pi }{5}cm/s$

Because there is no acceleration

Hence, change in velocity is Zero.