a)The rpm is 3540 rev/ min
1 rev = 2Ï€r, where r is the radius,
Therefore, the velocity
     =3540 ×2π ×4.5/100Â
     = (1001.04)/60
     = 16.684 m/s
b) ω = 2πf , where ω is the angular velocity and f is the frequency (oscillations) per second
=2Ï€ (3540/60)Â
= 2Ï€ (59)
= 370.756 rad/sec
a(max) = (370.756)² × 0.045Â
      = 6185.70 m/s²
      = 6.186 km/s²