[填空题]
A cooling fan is turned off when it is running at 850rev/min It turn8+g z o ul1 p4wd8o*3jqlfnv/hscf )9tp5dex8l p-)k(nb 0pwsb 1500 revolutions before it cow5()tpkclf nbse0b9 -)pd8x pmes to a stop. (a) What was the fan’s angular acceleration, assumed constant? $\frac{rad}{s^2}$ (b) How long did it take the fan to come to a complete stop? s