Question

A wet, open umbrella is held vertical and is twirled about the handle at a uniform rate of $21$ revolutions per $44$ seconds, then the angular speed of the umbrella is:

• A. $3$ radian.sec
• B. $1.5$ radian/sec
• C. $1$ radian/sec
• D. $\sqrt{2.5}$ radian/sec

Answer 1

The correct option is A $3$ radian.sec

Frequency of the rotation $f=\frac{21}{44}$ r.p.s

Angular velocity $w=2\pi f$

$⟹w=2\times \frac{22}{7}\times \frac{21}{44}=3rad/s$