How long does it take a wheel that is rotating at 33.3 rpm to speed up to 78 rpm if it has an angular?

Question

acceleration of 2.15 rad/s^2?

Answer 1

Well, 2.15 radians/s^2 is .342 times the circumfrence.
So, to speed up from 33.3 rpm to 34.3, you need 1/.342 seconds
to get to 78, you need (78-33.3)/.342 seconds, or
131 seconds.