[填空题]
The blades in a blender rtz-b 9+u 6np8s: rwgoko2fou.q a8qf 1ytate at a rate of 6500 rpm. When the motor is turned off uo 18fa2yf .qqduring operation, the blades slow to rest in 3.0 s. What is the angular acceleration as the blades slow down? $rad/s^2$