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Any physical quantity can be expressed by using as fundamental unit either energy, mass, length or time.
\begin{align} ct&\approx&\ell\Longrightarrow {\rm time}\approx{\rm length},\\ E&\approx& mc^2\Longrightarrow {\rm energy}\approx{\rm mass},\\ E&\approx& pv\Longrightarrow {\rm energy}\approx{\rm momentum},\\ Et&\approx& \hbar\Longrightarrow {\rm energy}\approx{\rm (time)^{-1}}\approx {\rm (length)^{-1}}. \end{align}