A CD has a diameter of 12.0 cm. If the CD is rotating at a constant angular speed of 20.0 radians per second, then the period of the rotational motion is
A) 0.143 s.
B) 0.224 s.
C) 0.314 s.
D) 0.421 s.
E) 0.558 s.

Question

Quizplus · Accepted Answer

The period of rotational motion (T) is the time it takes to complete one full rotation, which is given by $T = \frac{2\pi}{\omega}$, where $\omega$ is the angular speed. Substituting $\omega = 20.0 \, \text{radians per second}$, we get $T = \frac{2\pi}{20} = 0.314 \, \text{seconds}$.

A CD Has a Diameter of 12