# Homework Help: Conversion Question

1. Jun 2, 2007

### MJC8719

A centrifuge is a common laboratory instrument that separates components of differing densities in solution. This is accomplished by spinning a sample around in a circle with a large angular speed. Suppose that after a centrifuge in a medical laboratory is turned off it continues to rotate with a constant angular deceleration for 16.7 s before coming to rest.

(a) If its initial angular speed was 3170 rpm, what is the magnitude of its angular deceleration?
rev/s2

(b) How many revolutions did the centrifuge complete after being turned off?
rev

I believe I have found the answer in radians/s^2 and radians and was wondering how to convert them to rev/s^2 and revs.

Below is my work:

(a) 3170 x 2pi/60 x 1/16.7 = -19.8779 radians/s^2

(b) (1/2)(3170 x 2pi/60) x 16.7 = 2771.877 radians

2. Jun 2, 2007

### CaptainZappo

There are 2pi radians in one revolution. This should be all you need to convert.

Also, note that part (a) calls for the magnitude of the angular acceleration; thus, a sign (+ or -) is not needed.