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Is this correct please for my conversion from RPM to per second? I've included my working below:

(500 / 60) * 2 * π = 500 rpm to just s-1.

Transistor
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Herbert
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    I assume you're a younger poster, but you can easily find this by just Googling instead of needing to specifically ask. But no, it is not correct. You asked for rotations per second, not radians per second. – DKNguyen Feb 21 '22 at 14:20
  • Sorry I don’t mean rotations per second, but just per second – Herbert Feb 21 '22 at 14:52
  • You can't say "just per second". You must say what kind of event or phenomenon you are counting per second, along with appropriate units. – Elliot Alderson Feb 21 '22 at 14:54
  • "Just per second" is meaningless. Even Hz is technically cycles per second. In this case one rotation would be one cycle. – DKNguyen Feb 21 '22 at 14:54
  • @DKNguyen, $s^{-1}$ is common in Germany. I've seen it on many machine displays to indicate rotary speed or cycles per second. Usually the label prefixing the numerical display would make it clear what is being counted per second. – Transistor Feb 21 '22 at 15:32
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    @Transistor That's just Hz which is cycles per second, since cycles is often omitted because...reasons(?), but doesn't change the fact OP does not really understand what it is they are reading or asking for. – DKNguyen Feb 21 '22 at 15:33
  • @Herbert per second means how many every second ... it does not specify how many of what? – jsotola Feb 21 '22 at 18:58

2 Answers2

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60 RPM = 1 s-1.

To convert RPM to s-1 you divide by 60. You only need π if you are dealing in radians.

Transistor
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  • Hi, sorry im confused, is this still correct even if I want to get rid of the revolutions and just make it per second please? – Herbert Feb 21 '22 at 14:51
  • Think! If something rotates once per second how many times will it rotate in a minute? In two minutes? In ten minutes? (RPM = revolutions per minute, not radians per minute.) – Transistor Feb 21 '22 at 14:56
  • @Herbert That's impossible. Your problem is the understanding of units, not any conversion calculation. – DKNguyen Feb 21 '22 at 14:57
  • The $s^{-1}$ is the same as $/s$ and implies revolutions / second. – Transistor Feb 21 '22 at 16:04
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So for 1020rpm

1020/60 revs per second ie 17 revs per second

Solar Mike
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