From: dmitry@elros.cbb-automation.de (Dmitry A. Kazakov)
Subject: Re: Another Idea for Ada 20XX
Date: Mon, 10 Dec 2001 09:01:17 GMT
Date: 2001-12-10T09:01:17+00:00 [thread overview]
Message-ID: <3c1472cf.1156093@News.CIS.DFN.DE> (raw)
In-Reply-To: 7KbQ7.11747$wL4.10839@rwcrnsc51
On Fri, 07 Dec 2001 22:51:47 GMT, "Mark Lundquist"
<mlundquist2@attbi.com> wrote:
>
>"Philip Anderson" <phil.anderson@amsjv.com> wrote in message
>news:3C0F8E75.4F5CB3B8@amsjv.com...
>> Mark Lundquist wrote:
>> >
>> <snip>
>> > Units are unlike types in that they are optional (think about it, what
>units
>> > would you give for Pi?).
>> <snap>
>>
>> I don't think units are "optional", although they may be dimensionless,
>> ie just numbers like Pi.
>
>Eh? OK, so I'll ask again, what units would you give for Pi?
>
>> Note that radians, being a ratio, are actually
>> dimensionless.
>
>No, they are not!
>
>(BTW rate is also the ratio of distance/time, and of course rate isn't
>dimensionless -- any more than radians are!)
>
>The dimension of angle is distance/distance. (I'm not making this up -- the
>SI define radians in terms of meter*(meter**-1)).
There are lot of formulae involving Pi, which you can derive Pi units
from. Consider formula of volume, or better Euler's -1= exp (j*Pi)
(:-)).
>That's why when you
>multiply a distance by an angle, you get a distance. But if you were to
>multiply a mass by an angle, you do not get a mass (which would make it a
>unit conversion), but something whose units would be "kg-radians". (What
>use would that have? Beats me, for all I know there might be one... I'm a
>physics 'tard, my wise-ass PhD little brother got all the physics genes :-)
>:-)
>
>Dimensionless numbers do not change the units when you multiply them, that's
>the difference. No measurement is dimensionless.
This includes dimensionless numbers as well. For instance, when we
count, the result is measured in fingers (:-)).
Regards,
Dmitry Kazakov
next prev parent reply other threads:[~2001-12-10 9:01 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-12-02 19:51 Another Idea for Ada 20XX Gautier Write-only-address
2001-12-02 22:36 ` James Rogers
2001-12-03 12:44 ` Marc A. Criley
2001-12-03 14:29 ` Larry Kilgallen
2001-12-04 0:25 ` Marc A. Criley
2001-12-04 1:40 ` Adrian Hoe
2001-12-04 1:56 ` Larry Kilgallen
2001-12-04 16:08 ` Wes Groleau
2001-12-04 17:48 ` Larry Kilgallen
2001-12-09 23:02 ` Nick Roberts
2001-12-10 16:22 ` Stephen Leake
2001-12-10 17:11 ` Wes Groleau
2001-12-10 20:30 ` Robert C. Leif, Ph.D.
2001-12-10 20:59 ` Wes Groleau
2001-12-10 17:09 ` Wes Groleau
2001-12-10 17:32 ` Larry Kilgallen
2001-12-04 19:59 ` Vincent Marciante
2001-12-04 20:20 ` Wes Groleau
2001-12-04 22:18 ` Matthew Heaney
2001-12-06 4:14 ` Richard Riehle
2001-12-06 17:39 ` Wes Groleau
2001-12-07 0:55 ` Adrian Hoe
2001-12-07 9:01 ` Dmitry A. Kazakov
2001-12-07 11:49 ` Tarjei T. Jensen
2001-12-07 22:51 ` Dimensions (was Re: Another Idea for Ada 20XX) Mark Lundquist
2001-12-08 3:52 ` Richard Riehle
2001-12-08 5:28 ` Mark Lundquist
2001-12-08 18:59 ` Matthew Heaney
2001-12-08 21:23 ` Wes Groleau
2001-12-09 22:15 ` Robert C. Leif, Ph.D.
2001-12-10 14:09 ` Ian
2001-12-03 14:56 ` Another Idea for Ada 20XX Mark Lundquist
2001-12-06 15:27 ` Philip Anderson
2001-12-07 22:51 ` Mark Lundquist
2001-12-10 9:01 ` Dmitry A. Kazakov [this message]
-- strict thread matches above, loose matches on Subject: below --
2001-12-02 21:24 Gautier Write-only-address
2001-12-03 14:56 ` Mark Lundquist
2001-12-02 16:01 James Rogers
2001-12-02 16:38 ` Preben Randhol
2001-12-02 22:26 ` James Rogers
2001-12-02 21:19 ` Patrick Hohmeyer
2001-12-02 21:26 ` Lutz Donnerhacke
2001-12-02 23:49 ` Patrick Hohmeyer
2001-12-03 6:06 ` Wilhelm Spickermann
2001-12-03 8:58 ` Lutz Donnerhacke
2001-12-03 13:40 ` Thomas Koenig
2001-12-03 0:21 ` Robert C. Leif, Ph.D.
2001-12-03 0:35 ` Robert Dewar
2001-12-03 1:33 ` James Rogers
2001-12-03 12:34 ` Dirk Dickmanns
2001-12-03 14:56 ` Mark Lundquist
2001-12-03 15:12 ` Lutz Donnerhacke
2001-12-03 17:00 ` chris.danx
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