Angular momentum

Definition

Angular momentum is the quantity of rotation an object has, which depends on its mass, shape, and rotational velocity. It is a conserved quantity in an isolated system, meaning it remains constant if no external torque acts on the system.

5 Must Know Facts For Your Next Test

1. Angular momentum is given by the formula L = r x p, where r is the position vector and p is the linear momentum.
2. In a closed system with no external forces, angular momentum remains constant (conservation of angular momentum).
3. The units of angular momentum are kilogram meter squared per second (kg·m²/s).
4. Angular momentum plays a crucial role in understanding planetary orbits and how they change under gravitational interactions.
5. Kepler's second law of planetary motion can be derived from the conservation of angular momentum.

Review Questions

• What factors determine an object's angular momentum?
• Explain the principle of conservation of angular momentum and provide an example related to planetary motion.
• How does angular momentum relate to Kepler's laws of planetary motion?

Related terms

Torque: a measure of how much a force acting on an object causes that object to rotate.

Linear Momentum: the product of an object's mass and its velocity.

Kepler's Laws:

three laws describing the motions of planets around the Sun.