At time$$t$=0$t$=0$a grinding wheel has an angular velocity of $26\mathrm{.}0$rad$/$srad$/$s$.$ It has a constant angular acceleration of $35\mathrm{.}0$rad$/$s$2$rad$/$s$2$until a circuit breaker trips at time$$tt$=1\mathrm{.}90$ss$.$ From then on$,$ the wheel turns through an angle of $431$radrad$$as it coasts to a stop at constant angular deceleration.

At what time does the wheel stop?

What was the wheel's angular acceleration as it slowed down?