Mr. H turns on his fan and the three blades (25 cm each) experience a ccw angular acceleration of 3 rad/s/s. What is the angular displacement after the first 20 seconds. ? At the end of the day when Mr. H turns off his fan, he notices that it takes 45 seconds to come to rest. If the running speed of the fan is 240 rad/s, then what is the average angular deceleration? And how many revolutions did the fan rotate through?