Definition

1. Noun:
   • A physics quantity: Angular momentum is the rotational equivalent of linear momentum. It is a measure of the amount of rotation an object has, taking into account its mass, shape, and speed of rotation.
   • A conserved property: In a closed system with no external torque, the total angular momentum remains constant. This principle is fundamental in physics.

Usage Examples

• Noun:
  • The angular momentum of the spinning ice skater increases when she pulls her arms in.
  • Conservation of angular momentum explains why a planet's orbit is stable.
  • Calculating the angular momentum requires knowing the object's moment of inertia and angular velocity.

Advanced Usage

• "Conservation of angular momentum": A fundamental law of physics stating that if no external torque acts on a system, its total angular momentum remains unchanged.

  • The conservation of angular momentum is why a spinning top stays upright.

• "Spin angular momentum": Angular momentum associated with an object's intrinsic rotation about its own axis, distinct from orbital angular momentum.

  • Electrons possess an intrinsic form of angular momentum called spin.

• "Orbital angular momentum": Angular momentum associated with the motion of an object along an orbit or path around a point.

  • The Earth has orbital angular momentum from its revolution around the Sun.

Variants and Related Words

• Momentum (n): The quantity of motion of a moving body, measured as a product of its mass and velocity. (Linear momentum is the counterpart to angular momentum).
• Torque (n): A force that causes rotation or a change in angular momentum.
• Moment of inertia (n): A measure of an object's resistance to changes in its rotation rate, crucial for calculating angular momentum.

Synonyms

• Rotational momentum: A direct synonym emphasizing the rotational nature of the quantity.
• Moment of momentum: An older, less common term with the same meaning.

Related Phrases

• "Angular momentum vector": Angular momentum is a vector quantity, meaning it has both magnitude and direction.
  • The direction of the angular momentum vector is perpendicular to the plane of rotation.

Related Concepts

• "Angular velocity": The rate at which an object rotates or revolves, expressed in radians per second.
• "Gyroscopic stability": The stabilizing effect resulting from the conservation of angular momentum, as seen in gyroscopes and bicycles.

Noun

1. the product of the momentum of a rotating body and its distance from the axis of rotation
   • any rotating body has an angular momentum about its center of mass
   • angular momentum makes the world go round