$$\require{cancel}$$
In a similar way, if a particle at position $$\textbf{r}$$ has linear momentum $${\bf p } = m {\bf v}$$ , its moment of momentum with respect to the origin is the vector $$\textbf{l}$$ defined by
$\textbf{l} = \textbf{r} \times \textbf{p} \label{eq:3.3.1}$
and its components are the moments of momentum with respect to the axes. Moment of momentum plays a role in rotational motion analogous to the role played by linear momentum in linear motion, and is also called angular momentum. The dimensions of angular momentum are $$ML^{2}T^{-1}$$. Several choices for expressing angular momentum in SI units are possible; the usual choice is J s (joule seconds).