Convert Centrifuge Angular Speed/Deceleration to Rev/s2 and Revs

[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

 

[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.

 

[m2003]

To convert from radians to revolutions, we can use the conversion factor of 1 revolution = 2pi radians. Therefore, the answer for (b) in revolutions would be 2771.877/2pi = 441.991 rev.

To convert from radians/s^2 to rev/s^2, we can use the conversion factor of 1 revolution = 2pi radians and 1 second = 1/60 minutes. Therefore, the answer for (a) in rev/s^2 would be -19.8779 x 2pi x 60 = -2375.47 rev/s^2.