Representation of units with abbreviations

[GreenPrint]

Homework Statement

I just now came to the realization that I don't know the standard for representing units. When do I include "." after the abbreviation and when do I not? Thanks.

For example
mi. or mi
m or m.
yr. or yr

What's the rule? I'm sure there's got to be some general rule to apply to all units instead of memorizing weather or not to use it or not for each unit.

Homework Equations

The Attempt at a Solution

 

[amy andrews]

Abbreviations for metric units don't end in periods, but abbreviations for everything else, except those with "per," (such as mph) do.
Who knows why...

 

[GreenPrint]

hm thanks... one last question about units

 

[GreenPrint]

What's the convention for units on graphs like if you wanted to include units on a axis?
I remember in elementary school they always told us
Time (m)
would it be improper to just do
Time m
without putting the units in "()"?

 

[amy andrews]

Well I'm not absolutely sure on this one. But I think it is convention to put the units in parentheses...it's a sort of side note, so it should be in parentheses. It would look wrong to have it without.

 

[cupid.callin]

Abbreviations for metric units don't end in periods, but abbreviations for everything else, except those with "per," (such as mph) do.
Who knows why...

Wow. new thing to learn.