[填空题]
The tires of a car make 85 bw c0e26oadijj4*;/ qfpk :qt revolutions as the cwgf,;hm2 ; bxyar reduces its speed uniformly from 90km/h to 60km/h The;2x,h;y mwg fb tires 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