[填空题]
The blades in a blender 3 bkx;9p/*lpyjf6f c bberfh2 n5+4bdrotate at a rate of 6wdgrf4seq+ +/500 rpm. When the motor is turned off during operation, the blades 4r e +df/sg+qwslow to rest in 3.0 s. What is the angular acceleration as the blades slow down? $rad/s^2$