[填空题]
The blades in a blender qsp -(7p wf*ru:yh 2eprotate at3acr l0,+c r 9m 6ydamf-xp;uj a rate of 6500 rpm. When the motor is turned off during operation, the blades slow+a- d9rp l uf am6ry3;0m,cxcj to rest in 3.0 s. What is the angular acceleration as the blades slow down? $rad/s^2$