% scaled.tex — automatic factor-of-ten extraction.
%
% Tick magnitudes outside [1e-2, 1e4] are absorbed into the axis
% label as a 10^n factor; PGFPlots' "scaled ticks" keep tick numbers
% small.  Here the energy axis spans 0..5e7 J, so the y-label becomes
% "E (10^7 J)".

\documentclass{article}
\usepackage{siunitx}
\usepackage{numodel-plot}

\begin{document}

\def\xmin{0}\def\xmax{100000}
\def\ymin{0}\def\ymax{50000000}
\def\xlabelqty{t}\def\xlabelunit{\s}
\def\ylabelqty{E}\def\ylabelunit{\J}

\drawplot{
  \addplot[domain=\xmin:\xmax,thick,samples=50]{500*x};
  \addlegendentry{$E = P\,t$ met $P = \qty{500}{\W}$}
}

\end{document}