FIrst let's convert the angular distance covered by the wheel into radians. We know that
[tex]1 rev = 2 \pi rad[/tex]
Therefore, 2 revolutions correspond to
[tex]2 rev = 4 \pi rad[/tex]
The average angular speed of the wheel is given by the ratio between the angular displacement and the time taken:
[tex]\omega = \frac{\theta}{t} [/tex]
where in our problem, [tex]\theta = 4 \pi rad[/tex] and t=4.0 s, so the angular speed of the wheel is
[tex]\omega = \frac{\theta}{t}= \frac{4 \pi rad}{4.0 s}= \pi rad/s =3.14 rad/s [/tex]
