[填空题]
The blades in a blenw z2. bfo;qa w.(njs90x1ooomder rotate at a rate of z0vefbh(v4n9 6500 rpm. When the motor is turned off during operab 9(4v0nzfh evtion, the blades slow to rest in 3.0 s. What is the angular acceleration as the blades slow down? $rad/s^2$
