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*From*: John Denker <jsd@av8n.com>*Date*: Wed, 27 Jan 2010 05:48:44 -0700

On 01/27/2010 01:33 AM, James McLean wrote in part:

... why not define the unit 'cycle' = 2pi radians, and then make

1 Hz = 1 cycle/s = 2pi radians/s = 2pi/s ?

That makes sense ... and is indeed the only definition

I have ever used, or ever heard of, until now.

I've always been mildly disturbed by the definition of the unit hertz as

equivalent to 1/second. (Such as can be found, for example, at

<http://physics.nist.gov/cuu/Units/units.html> and

<http://physics.nist.gov/cuu/Units/SIdiagram.html>.

I'm surprised. I've never noticed that before. It

looks like a bug to me.

Can anyone see any problems with this [radian] option, other than the near

impossibility of changing tradition?

It's not a problem. It's not even a change. Radians

and radians per second (not cycles per second) are

already traditional throughout mathematics, throughout

electrical engineering, and in every physics book I

can think of.

I cannot imagine any argument in favor of cycles/sec

as equivalent to 1/sec. I have to assume that those

two NIST pages are just mistakes.

Suggestion: Send a short note to the NIST guys and

suggest they repair the web page to show Hz as

2π radians per second? Or call 'em on the phone.

I would hope a very short note would suffice. That

is, I hope it is not necessary to argue the point.

It should suffice to say that 2π radians per second

is consistent with the other units on the page, and

s^-1 is not consistent. I cannot imagine there would

be any sort of counterargument.

You could start with Thomas O'Brian, chief of the

Time and Frequency division. Whether or not he's

the exact right guy to handle this, it's his job to

know who the right guy is.

http://physics.nist.gov/cgi-bin/StaffOrg/stafftable.pl?direct_group=847&guestbox=1&edit=0

**Follow-Ups**:**Re: [Phys-l] frequency: a modest proposal***From:*Bernard Cleyet <bernardcleyet@redshift.com>

**References**:**[Phys-l] frequency: a modest proposal***From:*James McLean <mclean@geneseo.edu>

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