[填空题]
The tires of a car make 85 revolution7fssyqb +a4l(g (+tp bs as the car redukgknkpw a1f y83 bd:;0ces its speed uniformly from 90km/h to 60km/h The tirek1gb;kk3: 0wn p8day fs have a diameter of 0.90 m. (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