Angular Deceleration Calculation for Medical Lab Centrifuge

[ScienceGirl90]

Homework Statement

A medical laboratory centrifuge is rotating at 377 rad/s (3600 rpm). When it is switched off, it rotates 78 times before it comes to rest. Assuming constant angular deceleration, what is the angular deceleration?

Homework Equations

w=at+w_(initial)

The Attempt at a Solution

I'm confused as to what is my initial and final angular velocity and how to generally solve the problem with the info provided. My first thought was to make 377 rad/s be my initial velocity and 78 rad/s be the final velocity but I don't think that's right...

 

[tiny-tim]

Hi ScienceGirl90!

You know the initial angular speed, the final angular speed (zero), and the total angular distance, but not the time …

so use one of the other standard constant acceleration equations.

 

[ScienceGirl90]

Oh ok! So then 78 rotations is the distance then?

 

[tiny-tim]

(just got up :zzz: …)

Yup!