Question: A cooling fan is turned off when it is running at 850 rev/min. It turns 1500 revolutions before it comes to a stop. A. What is the fan's angular acceleration? B. How long does it take for the fan to come to a stop? I am pretty stumped with this question. I know that I have to use the equation a= omega (angular velocity)/ time ........and angular velocity= Change in theta/time ....but i am not sure how to go about the problem .......can anyone help?