I understand that something like \SI{5}{\meter\per\second}
defines a certain space between the number (5) and units (m/s). What should I use if instead of a numerical quantity I want a variable: R m/s? \SI{R}{\meter\per\second}
fails because it expect a number in first parameter, and R \si{\meter\per\second}
or $R$ \si{\meter\per\second}
show different space.
Which is the correct use?
\documentclass{standalone}
\usepackage{siunitx}
\sisetup{per-mode=symbol}
\begin{document}
\begin{tabular}{r}
\SI{5}{\meter\per\second}\\
$R$ \si{\meter\per\second}\\
R \si{\meter\per\second}\\
\end{tabular}
\end{document}
$R\cdot u$, where $u$ is \SI{1}{\meter\per\second}
.