1.(a)When a record player is stopped, the turnabble initially rotating at 33.3rpm,slows down and stops 60s.Calculate the angular acceleration of the turnable.(b)a grinding wheel when turned on,accelerates with an agnular acceleration of 50rad/s^2 . How much time is required to attain a final angular velocity of 1800rpm?

Both of these are asking you to use the definition of

angular acceleration=changeinAngularvelocity/time

change the rpm given to angular velocity in radians per sec.