Could someone please tell me how to calculate the following...?

The angular displacement Θ radians of a flywheel varies with time $\displaystyle "t"$seconds and follows the equation Θ$\displaystyle = 9t^2 - 2t^2$

Determine:

a)The angular velocity and acceleration of the flywheel when time $\displaystyle "t"$ = 1 Second

b) The time when the angular acceleration is zero.

Many thanks in advance.