Angular Acceleration of a rotating wheel

[TrippingBilly]

A rotating wheel requires 2.98 s to rotate through 37.0 revolutions. Its angular speed at the end of the 2.98 s interval is 98.8 rad/s. What is the constant angular acceleration of the wheel?

First I tried acceleration = (98.8rad/s - 0 rad/s) / 2.98 s - 0s = 33.15, which was incorrect.

Then I tried acceleration = (98.8rad/sec)^2 - (0 rad/sec)^2 = 2 * acceleration * 74pi and solving for acceleration i got 20.99 but that's incorrect too. I got 74 pi by converting 37 rev.

Any clue as to what I'm doing wrong?

 

[OlderDan]

A rotating wheel requires 2.98 s to rotate through 37.0 revolutions. Its angular speed at the end of the 2.98 s interval is 98.8 rad/s. What is the constant angular acceleration of the wheel?

First I tried acceleration = (98.8rad/s - 0 rad/s) / 2.98 s - 0s = 33.15, which was incorrect.

Then I tried acceleration = (98.8rad/sec)^2 - (0 rad/sec)^2 = 2 * acceleration * 74pi and solving for acceleration i got 20.99 but that's incorrect too. I got 74 pi by converting 37 rev.

Any clue as to what I'm doing wrong?

If all the information given in the problem is correct, the wheel is not starting from rest.

 

[TrippingBilly]

Huh, I guess I never considered that. That's frustrating :\ Thanks for your help though :)

 

[TrippingBilly]

never mind, i got it :)

 

[OlderDan]

never mind, i got it :)

I thought you had it when you posted your previous reply. Sorry if you were expecting something more.

Huh, I guess I never considered that. That's frustrating :\ Thanks for your help though :)

 

[TrippingBilly]

Oh no, I stopped looking at the problem for a while. But I decided to come back to it, and I had posted another question, but in the meantime I figured out the answer so I edited my post to the one you quoted. No worries :)