Question

The angular position of one of the blades of a fan is ${\theta }_1=\frac{\pi }{3}\text{rad}$, as shown in the figure. If the fan is switched on and off within a fraction of a second, the blade’s angular position changes to ${\theta }_2=\frac{\pi }{2}\text{rad}$. The angular displacement of all the blades is

• A. $\frac{\pi }{6}\text{rad}$
• B. $\frac{\pi }{4}\text{rad}$
• C. $\frac{\pi }{6}\text{degrees}$
• D. $\frac{\pi }{4}\text{degrees}$

Answer 1

The correct option is A $\frac{\pi }{6}\text{rad}$

We know that the angular displacement is given by
$\Delta \theta ={\theta }_2-{\theta }_1$
$=\frac{\pi }{2}-\frac{\pi }{3}$
$=\frac{\pi }{6}\text{rad}$