Question

The angular speed of a propeller on a boat increases with constant acceleration from 12 rad/s to 26 rad/s in 2.5 revolutions. What is the acceleration of the propeller?

Answer 1

Angular acceleration = (26 - 12)/Time

For the Time, use this equation

(Avg. Angular speed) x time
= 2.5*2 pi radians

Time = 0.827 s

Angular Acceleration
= [14 rad/s]/0.827 s
= ? rad/s^2

Answer 2

how is 2.5 x 2pi equal 0.827? Am I missing something?

Answer 3

2.5 x 2pi = Average Angular speed * time,
so
(2.5 x 2pi)/(average angular speed)=time