As we know the relation between linear speed and angular speed as
[tex]v = R\omega[/tex]
we will say
[tex]v = 8 m/s[/tex]
[tex]R = 0.05 m[/tex]
so here we can say that angular speed will be given as
[tex]\omega = \frac{8}{0.05}[/tex]
[tex]\omega = 160 rad/s[/tex]
so it is rotating at angular speed 160 rad/s