[Tex/LaTex] Left-aligning specific text in math-mode

Question

I currently have

via

\documentclass{scrartcl}
\KOMAoptions{
  fontsize = 10pt   ,
  headings = normal ,
}
\usepackage{amsmath}
\usepackage{multicol}
\usepackage{siunitx}
\begin{document}
\begin{multicols*}{2}
\section*{Electric Charge}
\textsf{Coulomb's Law} describes the electrostatic force between point electric charges $q_1$ and $q_2$ at (or nearly at) rest and separated by distance r:
%
\begin{align}
  F_c &= \frac{1}{4\pi\epsilon_0}\frac{|q_1||q_2|}{r^2} = \frac{k|q_1||q_2|}{r^2}\\
  \text{where} \quad e_0 &= \SI{8.85e-12}{\coulomb\squared\per\newton\per\meter\squared}\\
  \text{and} \quad k &= \SI{8.99e9}{\newton\meter\squared\per\coulomb\squared}
\end{align}
\end{multicols*}
\end{document}

and wish to produce the following:

Coulomb's Law describes the electrostatic force
between point electric charges q1 and q2 at (or
nearly at) rest and separated by distance r:

           F = (1/4πe_0)(|q1||q2|)/r^2      (1)
where     e0 = 8.85*10^-12 C^2/N*m^2        (2)
and        k = 8.99*10^9 N*m^2/C^2          (3)

In math-mode, how would I left-align specific text (e.g., via a command) such that the text is pushed as far to the left as possible? I wish to preserve the default centered style in math-mode.

Answer 1

Given the rather narrow text measure that's in effect, I can't help but feel but that this example would be suited ideally for use of the \shortintertext command provided by the mathtools package (a superset of the amsmath package).

\documentclass{scrartcl}
\KOMAoptions{fontsize = 10pt, headings = normal}
\usepackage{mathtools}
\usepackage{multicol}
\usepackage{siunitx}
\newcommand{\abs}[1]{\lvert#1\rvert}
\begin{document}
\begin{multicols*}{2}
\section*{Electric Charge}
\textsf{Coulomb's Law} describes the electrostatic force between 
point electric charges $q_1$ and $q_2$ at (or nearly at) rest and 
separated by distance~$r$:
\begin{align}
  F_c &= \frac{1}{4\pi\epsilon_0}\frac{\abs{q_1}\abs{q_2}}{r^2} 
          = \frac{k\abs{q_1}\abs{q_2}}{r^2}\\
\shortintertext{where}
  e_0 &= \SI{8.85e-12}{\coulomb\squared\per\newton\per\meter\squared}\\
\shortintertext{and}
   k &= \SI{8.99e9}{\newton\meter\squared\per\coulomb\squared}\,.
\end{align}
\end{multicols*}
\end{document}