Angular velocity is defined as
[tex]\omega = 2\pi f[/tex]
now we know that
frequency = number of revolutions per seconds
here we know that
N = 54.1 revolutions
t = 0.6 s
now from above definition we know that
[tex]f = \frac{N}{t}[/tex]
[tex]f = \frac{54.1}{0.6} = 90.17 rev/s[/tex]
now from above equation
[tex]\omega = 2\pi f[/tex]
[tex]\omega = 2\pi(90.17)[/tex]
[tex]\omega = 566.1 rad/s[/tex]