At time t=0 a grinding wheel has an angular velocity of 22.0 rad/s. It has a constant angular acceleration of 32.0 rad/s^2 until a circuit breaker trips at time t = 2.00 s. From then on, the wheel turns through an angle of 432 rad as it coasts to a stop at constant angular deceleration. What was the wheel's angular acceleration as it slowed down?