A circular saw blade rotating at 3600 rpm is braked to a stop in 6 seconds. What is the angular acceleration? How many revolutions did the blade make before coming to a stop?

Answer 1

Initial angular velocity = wo
= 3600*(2 pi)/60 = 377 rad/s
Angular acceleratiom = -wo/t
= -62.8 rad/s^2

Number of revolutions = (average angular velocity*t/(2 pi)
= (1/2)(377)*t/(2 pi) = 180
or average rpm*(1/10 minute)
= 3600*(1/2)*1/10)= 180