# Homework Help: Angular Velocity and Angular Acceleration

1. Mar 4, 2009

### Hotsuma

I feel really dumb, as this should be incredibly easy to figure out, but I keep getting the wrong answers. I am including the book's data so I can figure out how this needs to be done and then plug in my own values.

1. The problem statement, all variables and given/known data

Pilots can be tested for the stresses of flying high-speed jets in a whirling "human centrifuge," which takes 1.0 min to turn through 20 complete revolutions before reaching its final speed.

What is its angular acceleration (assumed constant) (in rev/min^2) and its angular velocity in rpm?

2. Relevant equations

Code (Text):

\theta (t) = \theta_0 +\omega_0t + \frac{1}{2}\alpha t^2
\omega (t) = \omega_0 + \alpha t.
[\CODE]

[b]3. The attempt at a solution[/b]

I have tried finding the frequency and then multiplying it by 2\pi, but I don't get the right answer. The book's values are:
Ang. Acc = 40 rev/min^2
Ang. Vel = 40 rpm

2. Mar 4, 2009

### lanedance

i think it might have something to do with your units

theta = (1/2).alpha.t^2

you want to find alpha in rev/min^2
so input theta in revolutions and t in mins to get the correct alpha

3. Mar 4, 2009

### Hotsuma

I don't think I have a value for theta unless it is 2pi. Even then, that is in radians not revolutions per minute.

4. Mar 4, 2009

### Hotsuma

Thanks LowlyPion, my answer for angular acceleration is correct and the concept is much more clear now. I'll let you know if I get angular velocity figured out, which should be easy from here.

5. Mar 4, 2009

### Hotsuma

To find Angular velocity I multiply angular acceleration by time. Thanks for the help.

6. Mar 4, 2009

### Hotsuma

I forget how to mark this as solved, also, does anyone know how to use direct LaTeX typesetting here?