Angular Accerlation Homework: Avg. Angular Acc in Rad/s2

[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

Change in Angular Accerlation/ Change in time

The Attempt at a Solution

I tried the above equation but the online homework says the answer is wrong. I'm not sure of what else to do.

 

[G01]

If you don't show your work, how can we know where you went wrong?

Also, your equation given is not an equation (there is no equal sign), but either way, change in acceleration/change in time is a rate of change of acceleration, which would not help you here. Did you mean this?

$$\alpha=\frac{\Delta \omega}{\Delta t}$$

 

[Moetasim]

Hello,

Thank you for reaching out with your question about angular acceleration. Based on the information provided, it seems like you are on the right track with your attempt at using the equation for average angular acceleration. However, it is important to note that the units for angular acceleration are typically in radians per second squared (rad/s^2).

In this case, the hard disk is spinning at a rate of 7200 rpm (revolutions per minute), which can be converted to radians per second by multiplying by 2π/60 (since there are 2π radians in one revolution and 60 seconds in one minute). This gives us an angular velocity of 754.38 rad/s.

To find the average angular acceleration, we can use the equation:

Average angular acceleration = (final angular velocity - initial angular velocity) / time

In this case, the final angular velocity is 754.38 rad/s, the initial angular velocity is 0 rad/s (since the hard disk starts from rest), and the time is 3.7 seconds. Plugging in these values, we get:

Average angular acceleration = (754.38 rad/s - 0 rad/s) / 3.7 s = 204.16 rad/s^2

I hope this helps and clarifies any confusion. Keep up the good work with your studies!