Conversion Question

  1. 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?

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

    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. jcsd
  3. 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.
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