Answer:
T = 8.19 s , Â [tex]v_{max}[/tex] Â = 23 m / s
Explanation:
In the simple harmonic motion the equation that describes them is
  y = A cos wt
Acceleration can be found by derivatives
  a = d²y / dt²
  v = dy / dt = - Aw sin wt
  a= d²y / dt² = - A w² cos wt
For maximum acceleration cosWT = + -1
  [tex]a_{max}[/tex] = -A w2
  w = RA ([tex]a_{max}[/tex]/ A)
  w = RA (1.8 9.8 / 30.0)
  w = 0.767 rad / s
The angular velocity is related to the frequency
  w = 2π f
   f = 1 / T
  w = 2π / T
  T = 2π / w
  T = 2π / 0.767
  T = 8.19 s
For maximum speed the sin wt = + -1
  [tex]v_{max}[/tex] = A w
  [tex]v_{max}[/tex]  = 30.0 0.767
  [tex]v_{max}[/tex]  = 23 m / s