Question

The angular speed of a flywheel making 120 revolutions/minute is

• A. 4 $\pi$ rad/s
• B. 4 ${\pi }^2$ rad/s
• C. $\pi$ rad/s
• D. 2 $\pi$ rad/s

Answer 1

Answer: (A)

Number of revolutions per minute $(n)=120$.
Therefore angular speed ( $\omega$)
= $\frac{2\pi n}{60}=\frac{2\pi \times 120}{60}=4\pi$ rad/s.