Question:
If OP makes 4 revolutions in one second, the angular velocity in radians per second is
(a) π
(b) 2 π
(c) 4 π
(d) 8 π
Solution:
(d) 8 π
Angular velocity $=\frac{\text { Distance }}{\text { Time }}$
$=\frac{4 \text { revolutions }}{1 \text { second }}$
$=\frac{4 \times 2 \pi}{1} \quad(\because 1$ revolution $=2 \pi$ radians $)$
$=8 \pi$ radians per second