Question

The blades in a blender rotate at a rate of 6800 rpm . When the motor is turned off during operation, the blades slow to rest in 2.8 s .

Answer 1

The angular acceleration of the blade when it's switched off is (-6800 rev/min) divided by (2.8 sec) = -2,428.6 rev/(min-sec) = -40.5 rev/sec^2 .