Answer:
w = 0.886 rad / s
Explanation:
Angular and linear variables are related
    a = α r
where a is the linear acceleration, α the angular acceleration and r the radius of gyration
     α = a / r
the angular velocity we can find it
     w² = w₀² + 2 α θ
the initial angular velocity is zero, the angles to be horizontal is
  θ = π/ 2  rad
  Â
we substitute
     w = √ 2 a / r  θ
we calculate
     w = √ (2 3/12 π/2)
     w = 0.886 rad / s