A turntable reaches an angular speed of 33.3 rpm, in 2.1 s, starting from rest what is the magnitude?

Answer 1

...of the angular acceleration? ...of the angle it went through while accelerating?
This is exactly like translational acceleration except that you need to convert rpm to rad/s. Then:
(translation)
a = v/t; x = vt/2
(rotation)
α = ω/t; Θ = ωt/2 ( Θ in rad, ω in rad/s, α in rad/s^2)