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What is angular momentum?
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The angular momentum of a body is defined with reference to a chosen point also called the origin. Angular momentum of a body is a cross product given by L = r x p, where r is the position vector of the body about the point chosen as origin and p is the linear momentum of the body. As linear momentum is a cross product of two vectors, it is a vector too and acts in a direction that is given by the right hand rule.
Angular momentum is expressed in the units N*m*s.
The angular momentum of a rotating body has many applications; a gyroscope does not fall over due to its angular momentum, a moving bicycle is stable and does not tip over due to the angular momentum of its wheels.
Posted by justaguide on November 20, 2011 at 3:38 AM (Answer #1)
angular momentum is moment of momentum, or rotational momentum is a conserved vector that states a particular measurable property of an isolated physical system does not change as the system evolves quantity that can be used to describe the overall state of a physical system. The angular momentum L of a particle with respect to some point of origin is
where r is the particle's position from the origin, p = mv is its linear momentum, and × denotes the cross product.
The angular momentum of a system of particles (e.g. a rigid body) is the sum of angular momenta of the individual particles. For a rigid body rotating around an axis of symmetry (e.g. the fins of a ceiling fan), the angular momentum can be expressed as the product of the body's moment of inertia I (a measure of an object's resistance to changes in its rotation rate) and its angular velocity ω:
In this way, angular momentum is sometimes described as the rotational analog of linear momentum.
Angular momentum is conserved in a system where there is no net external moment of force,
and its conservation helps explain many diverse phenomena. For example, the increase in rotational speed of a spinning figure skater as the skater's arms are contracted is a consequence of conservation of angular momentum. The very high rotational rates of neutron star can also be explained in terms of angular momentum conservation.
Posted by wanasyraf on November 20, 2011 at 2:23 PM (Answer #2)
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