Mathematica Stack Exchange is a question and answer site for users of Mathematica. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

Converting between revolutions per minute (RPM) and revolutions per second (RPS) is not straightforward for me in Mathematica.

I know that $1\; \text{RPM} = \frac{2\; \times\; \Pi\; \text{Radian}}{\text{Second}\; \times\; 60}$. To get RPS then, it is just a matter to remove the factor of $60$ in the denominator.

Taking a numerical example, I can convert say $500$ RPM to Hertz as follows:

$[\text{Convert}[\frac{500\; \times\; 2\; \times\; \Pi\; \text{Radian}}{\text{Second}\; \times\; 60}, \text{Hertz}],9]$

which gives me $52.3597776\; \text{Hertz}$

But now if I want to convert $500$ RPM to RPS, the following does not work as in the Convert command, the second argument has also numerical values in it:

$[\text{Convert}[\frac{500\; \times\; 2\; \times\; \Pi\; \text{Radian}}{\text{Second}\; \times\; 60}, \frac{2\; \times\; \Pi\; \text{Radian}}{\text{Second}}],9]$

which gives me as output: $\frac{52.3598776\; \text{Radian}}{\text{Second}}$ instead of the desired answer of about $8.33\:$ . The factor of $2\; \Pi$ is the troublemaker.

So how to do an appropriate conversion from RPM to RPS?

update:

I am using version 9.

Thank you.

share|improve this question
    
Which version of Mathematica are you using? – Mr.Wizard Dec 18 '13 at 9:45
    
If You are using Mathematica 9 You can try UnitConvert[] function. I'm using ver. 7.0 so I can't check if it works in Your case. – Wojciech Dec 18 '13 at 9:48
    
@Wojciech yes, N@UnitConvert[Quantity[500,"Revolutions"/"Minutes"], "Revolutions"/"Seconds"] does give the result 8.333... – cormullion Dec 18 '13 at 11:28
    
That one was pretty straightforward, since it is in the documentation center :) – Wojciech Dec 18 '13 at 11:49
    
As does UnitConvert[Quantity[500., "RPM"], "RPS"] – bobthechemist Dec 18 '13 at 13:55

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Browse other questions tagged or ask your own question.