From: dieter@duenenhof-wilhelm.de (H. Dieter Wilhelm)
To: help-gnu-emacs@gnu.org
Subject: Re: Getting used to Calc's Radian convention
Date: Sat, 13 Sep 2014 09:41:01 +0200 [thread overview]
Message-ID: <87vbosvugi.fsf@vsl28t2g.ww011> (raw)
In-Reply-To: 26301a71-0d4b-4ac5-bf8a-c1deb3f236bd@googlegroups.com
jay.p.belanger@gmail.com writes:
>> > Calc's unit convention of revolution per minute (rpm)
>>
>> > is derived from the angular speed and not from a
>>
>> > frequency. One does not need to type the factor of `2
>>
>> > pi' when calculating, for example, the
>>
>> > circumferential velocity from the radius and some
>>
>> > value in rpm. So far so good.
>>
>> >
>>
>> > But it has the slight aesthetic drawback that now the
>>
>> > velocity turns out to be in units of radians.
>>
>> >
>>
>> > n <- 1 rpm
>>
>> > r <- 1 m
>>
>> > n r -> 2 pi rad m / min
>
>
>> My thoughts are: What?!
>
> He's referring to Calc (part of Emacs), which can work with units
> (such as meters, radians, etc.)
Sorry, I made myself not clear and it is basically a question about
physics but there seems to be not separate Calc mailing list.
> Calc doesn't "know" that the rad probably shouldn't be there; perhaps
> there could be a simple way of telling it.
As I said I'm happy with the angular notion of Calc's rpm unit but
it. Maybe it would help to "degrade" Radian -- it is in Calc a base unit
-- to a constant like pi and when converting to base units it simply
vanishes when saying `u b' calc-base-units or an additional unit
function for converting it to its numerical value?
Have fun with Calc
--
Best wishes
H. Dieter Wilhelm
Darmstadt, Germany
next prev parent reply other threads:[~2014-09-13 7:41 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <mailman.8731.1410504469.1147.help-gnu-emacs@gnu.org>
2014-09-12 19:15 ` Getting used to Calc's Radian convention Emanuel Berg
2014-09-13 2:26 ` jay.p.belanger
2014-09-13 5:29 ` Emanuel Berg
2014-09-13 7:43 ` H. Dieter Wilhelm
2014-09-13 7:41 ` H. Dieter Wilhelm [this message]
2014-09-12 6:47 H. Dieter Wilhelm
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
List information: https://www.gnu.org/software/emacs/
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=87vbosvugi.fsf@vsl28t2g.ww011 \
--to=dieter@duenenhof-wilhelm.de \
--cc=help-gnu-emacs@gnu.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).