Question

A record player makes $60$ rpm (revolution per minute). Its angular velocity and its period are ____ ${rads}^{-1}$ and s ____ respectively.

• A. $2\pi ,1$
• B. $2\pi ,2$
• C. $\pi ,2$
• D. $\pi ,1$

Answer 1

The correct option is A $2\pi ,1$

$60$ revolutions per minute

$=60\times \frac{1}{60}$ revolutions per second

$=1$ revolution per second

$=1\times 2\pi$rotation per second

$=2\pi rad/s$

$\therefore$ angular velocity , $\omega =2\pi rad/s$

$\omega =\frac{2\pi }{T}$

$T=\frac{2\pi }{2\pi }=1s$