[boost] Re: Physical quantities

From: Deane Yang (deane_yang_at_[hidden])
Date: 2004-01-14 17:58:50

Deane Yang wrote:
> Andy Little wrote:
>> (Understating) I find this remark slightly odd. Deane has several times
>> asked myself and others to explain the concepts of physical 
>> quantities.
(stuff deleted)
> OK. (takes a deep breath). Here's one more try. I have NEVER said I do 
> not understand dimensional analysis.

I just remembered that this isn't quite right, and Andy does have a 
point (probably because he's read my early posts more recently than I have).

Way at the beginning,
I expressed some confusion about what a "dimension" was. I have yet
to see anyone articulate clearly and precisely what the definition
of a "dimension" is (please chime in if you have one!). Is it something
like this:

dimension = the general thing you are measuring (but in no particular 
quantity)

quantity = how much of the dimension you have in a particular circumstance
?

Then to turn a quantity into a number, you choose a unit for that dimension.