Answer
The angular speed of the sprocket tip is $22$ rev/s.
Work Step by Step
As point A comes to the rotating sprocket tip, the linear speed turns into the tangential speed, or $v_T=5.6m/s$
The sprocket tip's radius $r=4\times10^{-2}m$
The angular speed of the sprocket tip is $$\omega=\frac{v_T}{r}=140rad/s\times\Big(\frac{1rev}{2\pi rad}\Big)=22rev/s$$
