At t = 0 s a flywheel is rotating at 20 rpm. A motor gives it a constant acceleration of 1 rad/s^2 until it reaches 100 rpm. The motor is then disconnected. How many revolutions are completed at t = 21 s?
What I've done so far is multiply my 20rpm and 100rpm by (2pi/60) to get what I think is my Wo and Wf. I tried using kinematics with wf=wo+ang.acc x t and plugged in those values to find a t of 8.38 s. So I'm thinking it takes 8.38 s to get to 100rpm. I tried doing a proportion with 20rpm and 8.38s , and then one with 100rpm and (21-8.38s) , to then add the total rotations but that's not right.