Angluar acceleration of a computer disk

[cstout]

Homework Statement

During normal operation, a computer's hard disk spins at 7200 rpm. If it takes the hard disk 3.7 s to reach this angular velocity starting from rest, what is the average angular acceleration of the hard disk in rad/s2?

Homework Equations

Wav = $$\vartheta$$f - $$\vartheta$$i/Tf-Ti

The Attempt at a Solution

 

[kamerling]

Homework Statement

During normal operation, a computer's hard disk spins at 7200 rpm. If it takes the hard disk 3.7 s to reach this angular velocity starting from rest, what is the average angular acceleration of the hard disk in rad/s2?

Homework Equations

Wav = $$\vartheta$$f - $$\vartheta$$i/Tf-Ti

you want: Wav = ($$\vartheta$$f - $$\vartheta$$i)/(Tf-Ti)

Do you know what all the variables in this equation mean? It is the right equation so you just have to find out what all the variable are in express them in the right units

 

[cstout]

I got it now, I didn't convert the 7200 rpm to rad/s