# How to relate to math expressions that don’t have physical representations

• I
rasp
TL;DR Summary
I’m wondering how to get comfortable in using math terms in physics equations that do not have physical meanings. I know the formulas work but what are we saying about the terms? For example, I’m thinking of i in quantum wave equation and c^2 in Relativity I mean as c is the highest speed possible, what is c^2. I understand speed ^2 satisfies the dimensions, but how can we employ a number which violates our understanding of the maximum speed?
Thread is contained in the summary.

Staff Emeritus
but how can we employ a number which violates our understanding of the maximum speed?

Why do you think c2 is a speed? Is an acre an length?

• S.G. Janssens
dsaun777
Summary:: I’m wondering how to get comfortable in using math terms in physics equations that do not have physical meanings. I know the formulas work but what are we saying about the terms? For example, I’m thinking of i in quantum wave equation and c^2 in Relativity I mean as c is the highest speed possible, what is c^2. I understand speed ^2 satisfies the dimensions, but how can we employ a number which violates our understanding of the maximum speed?

Thread is contained in the summary.
Nothing is violating the speed of light when we describe rest energy as being equal to the rest mass times the square of the speed of light. This is just what energy is and how it is defined.