Angular momentum $\vec L$

The “toughness” of stopping something heavy which is spinning, or starting a spinning motion of something from rest.

$$\vec L=I\vec \omega$$

where $I$ is moment-of-inertia and $\vec \omega$ angular speed at impact. For separated objects/particles rotating, the angular momentum that each contributes with is:

$$\vec L=\vec r \times \vec p$$

where $\vec r$ is the object’s distance from the centre-of-rotation and $\vec p$ is it’s momentum.

• Vector property
• Symbol: $\vec L$
• SI-unit: Kilogram-times-metres-squared-per-second $\mathrm{kg\cdot m^2/s}$