# 3.3: Moment of Momentum

- Page ID
- 6942

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).