Angular momentum
Definition
Angular momentum is a measure of the quantity of rotation of an object and is a vector quantity. It is given by the product of the moment of inertia and angular velocity.
5 Must Know Facts For Your Next Test
- Angular momentum ($\vec{L}$) is conserved in a closed system with no external torques.
- The formula for angular momentum is $\vec{L} = I \vec{\omega}$, where $I$ is the moment of inertia and $\vec{\omega}$ is the angular velocity.
- Angular momentum has both magnitude and direction, making it a vector quantity.
- The unit for angular momentum in the International System (SI) is kilogram meter squared per second (kg·m²/s).
- In rotational motion, torque ($\tau$) causes a change in angular momentum according to $\tau = \frac{d\vec{L}}{dt}$.
Review Questions
- What are the units for measuring angular momentum?
- How does torque affect angular momentum?
- Explain how conservation of angular momentum works in a closed system.
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Related terms
Moment of Inertia: A measure of an object's resistance to changes in its rotational motion, dependent on mass distribution relative to the axis of rotation.
Torque: A force that causes rotation, calculated as the product of force and lever arm distance from the axis of rotation.
Angular Velocity: The rate at which an object rotates or revolves around an axis, measured in radians per second (rad/s).
