Substitution

[elas]

I am not a mathmatician but, to fully understand a book I am reading; I do need to know if a constant for force A can be sustituted with the constant for force B and if so, a reference to the rules would be apreciated.

(both being quoted in letters, not numbers although the do have numerical values in different [at present] non-convertable units).

Edited April 8, 2012 by elas

[mathematic]

The question is too vague. I suggest you give some more details.