At t=0 a grinding wheel has an angular velocity of 28.0 rad/s. It has a constant angular acceleration of 25.0 rad/s2 until a circuit breaker trips at time t = 1.90 s. From then on, it turns through an angle 436 rad as it coasts to a stop at constant angular acceleration.
(a) Through what total angle did the wheel turn between t= 0 and the time it stopped?
(b) At what time does the wheel stop?
(c)What was the wheel's angular acceleration as it slowed down? Express your answer in radians per second per second.