[填空题]
The tires of a car make 85 revolutions abwq lgr.8f;5gk5; aocs the caa6ci, mapv 0ubb78*d1,cz f isr reduces its speed uniformly from 90km/h to 60km/h The tires have a diameter of 0.90 m. zcci,7m0uv1i, ad*b 6f8apsb (a) What was the angular acceleration of each tire? $\approx$ $rad/s^2$(round to two decimal place) (b) If the car continues to decelerate at this rate, how much more time is required for it to stop? s