# Why is angular momentum perpendicular?

Aug 7, 2015

Angular momentum as you can tell from its name is related to the rotation of an object or a system of particles.

#### Explanation:

Having said that, we have to forget all about the linear and translational motion that we are so familiar with. Therefore, angular momentum is simply a quantity that shows rotation.

Look at the little curved arrow which shows angular velocity (likewise with angular momentum).

• The Formula *

$\vec{L} = m \left(\vec{r} \times \vec{V}\right)$
We have a cross product for the 2 vectors which shows that angular momentum is perpendicular to the radial vector, $\vec{r}$ and velocity vector $\vec{V}$. If $\vec{L}$ points up in your right hand rule, the direction is anti-clockwise and vice-versa.