[texhax] Units in technical writing

Johnny yggdrasil at gmx.co.uk
Thu Dec 29 22:00:55 CET 2011


Philip TAYLOR <P.Taylor at Rhul.Ac.Uk> writes:
>
> Read with great interest, Johhny, but this one worries me :
>
>> ampere 	 A
>>
>>     The ampere is that constant current which, if maintained in two
>> straight parallel conductors of infinite length, of negligible
>> circular cross-section, and placed 1 m apart in vacuum, would
>> produce between these conductors a force equal to 2 x 10–7 newton
>> per metre of length.
>
> At this point, the Newton has not been defined ...

This may be why it is also clarified in the same section that:

,----
| The expression “MKS unit of force” which occurs in the original text of
| 1946 has been replaced here by “newton”, a name adopted for this unit by
| the 9th CGPM (1948, Resolution 7; CR, 70).
`----

Of course, one could have used the definition of the Newton in Table 3
that N =  m kg s-2, as these are the units defined in the three
preceeding sections. But of course, Hz is mentioned in 2.1.1.3 and
presumably this must then be consequently expressed as
s-1. Unfortunately, in 2.1.1.3 there is a mention of K, which is not
defined until 2.1.1.5! 

Sorry about the discourse, but I believe that shouldn't be a course of
cocern. The text is rarely precise, but regardless of opinions on the
structure, I for one would be happy to simply see the *proper
capitalisation of units and prefixes* and a personal crusade:

,----
| The numerical value always precedes the unit, and a space is always used
| to separate the unit from the number.
`----

Happy new year!

-- 
Johnny



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