Sistem koordinat polar: Perbedaan antara revisi

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The term <math>r\dot\varphi^2</math> is sometimes referred to as the ''centrifugal term'', and the term <math>2\dot r \dot\varphi</math> as the ''Coriolis term''. For example, see Shankar.<ref name=Shankar>{{Cite book|title=Principles of Quantum Mechanics|author=Ramamurti Shankar|edition=2nd|page=81|url=http://books.google.com/?id=2zypV5EbKuIC&pg=PA81&dq=Coriolis+%22polar+coordinates%22|year=1994|isbn=0-306-44790-8|publisher=Springer}}</ref> Although these equations bear some resemblance in form to the [[centrifugal force|centrifugal]] and [[Coriolis effect]]s found in rotating reference frames, nonetheless these are not the same things.<ref name=angular>In particular, the angular rate appearing in the polar coordinate expressions is that of the particle under observation, <math>\dot{\varphi}</math>, while that in classical Newtonian mechanics is the angular rate Ω of a rotating frame of reference.</ref> For example, the physical centrifugal and Coriolis forces appear only in [[non-inertial frame]]s of reference. In contrast, these terms that appear when acceleration is expressed in polar coordinates are a mathematical consequence of differentiation; these terms appear wherever polar coordinates are used. In particular, these terms appear even when polar coordinates are used in [[inertial frame]]s of reference, where the physical centrifugal and Coriolis forces never appear.
 
[[Image:Co-rotating frame vector.svg|thumb|Inertial frame of reference ''S'' and instantaneous non-inertial co-rotating frame of reference ''S′''. The co-rotating frame rotates at angular rate &Omega;Ω equal to the rate of rotation of the particle about the origin of ''S′'' at the particular moment ''t''. Particle is located at vector position '''r'''(''t'') and unit vectors are shown in the radial direction to the particle from the origin, and also in the direction of increasing angle ''φ'' normal to the radial direction. These unit vectors need not be related to the tangent and normal to the path. Also, the radial distance ''r'' need not be related to the radius of curvature of the path.]]
 
=====''Co-rotating frame''=====
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* {{springer|title=Polar coordinates|id=p/p073410}}
* {{dmoz|Science/Math/Software/Graphing/|Graphing Software}}
* [http://www.random-science-tools.com/maths/coordinate-converter.htm Coordinate Converter &mdash; converts between polar, Cartesian and spherical coordinates]
* [http://scratch.mit.edu/projects/nevit/691690 Polar Coordinate System Dynamic Demo]