Changes
Reverted edits by [[Special:Contributions/Led Zeppelin IV|Led Zeppelin IV]] ([[User talk:Led Zeppelin IV|talk]]) to last revision by [[User:SamHB|SamHB]]
:<math> \mathbf{p} = m\mathbf{v} </math>
Hence, the faster an object goes, or the more mass it posessespossesses, the more momentum it has. Momentum is a [[vector]] quantity, and therefore has both a magnitude and direction. It is important to physicists because it is a [[conservation law|conserved]] quantity, making it useful for solving problems.
In common usage, the words "momentum" and "[[inertia]]" are sometimes used interchangeably. Inertia is the tendency for a body to resist changes in its motion until and unless a force acts on it.
==Angular momentum==
A rotating or orbiting body possesses angular momentum. Like linear momentum, angular momentum is a vector quantity and is [[Conservation of angular momentum|conserved]]. An object's angular momentum changes only when a [[torque]] is applied to it.It is defined as:
:<math>L=mvr</math>
where
*'''<math> L''' </math> is the magnitude angular momentum*'''<math> m''' </math> is the mass of the particle*'''<math> v''' </math> is the linear tangential [[velocity ]] of the particle*'''<math> r''' </math> is the distance from the particle to the origin
The direction of the angular momentum vector points perpendicularly to the plane formed by the object's orbit, in accordance with the [[right hand rule]].
In addition to orbital angular momentum, the earth has rotational angular momentum due to its spin. The equations for calculating rotational angular momentum depend on the object's [[moment of inertia]], and therefore the shape and density of the object. and can be given as: :<math>\vec{L} = I \vec{ \omega}</math> Where *<math>\vec{\omega}</math> is the angular momentum*<math> I </math> is the [[moment of inertia]]*<math>\vec{\omega}</math> angular velocity of the body
=== Generalized momentum ===
The definition of momentum can be generalized in [[Lagrangian Dynamics|Lagrangian]] and [[Hamiltonian Dynamics|Hamiltonian]] dynamics, to
as above.
== Momentum in Relativity == In [[relativity]], momentum must be redefined for conservation of momentum to be retained. It is defined as :<math> \mathbf{p}= \gamma m \mathbf{v}</math> where <math>\gamma</math> is the [[Lorentz factor]]. ==Momentum in Quantum Mechanics== In [[quantum mechanics]], the operator for momentum, <math>\hat p</math> is <math>\hat p = \frac{\hbar}{i} \frac{\partial}{\partial x}</math> ==External Linkslinks==*[http://id.mind.net/~zona/mstm/physics/mechanics/momentum/momentum.html MomemtumMomentum]
[[Category:Physics]]
[[Category:Mechanics]]
