Moment of inertia through scaling and the parallel axis theorem

Abstract A right triangular plate scaled by a factor two generates a bigger plate composed of four triangular plates the same size as the original. By using dimensional analysis we write the moment of inertia around the center of mass, for the original and the bigger plate, in terms of a common unkn...

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Main Author: Roberto Rojas
Format: Article
Language:Portuguese
Published: Sociedade Brasileira de Física
Series:Revista Brasileira de Ensino de Física
Subjects:
Online Access:http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1806-11172019000100801&lng=en&tlng=en
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author Roberto Rojas
author_facet Roberto Rojas
author_sort Roberto Rojas
collection DOAJ
description Abstract A right triangular plate scaled by a factor two generates a bigger plate composed of four triangular plates the same size as the original. By using dimensional analysis we write the moment of inertia around the center of mass, for the original and the bigger plate, in terms of a common unknown parameter. Through the parallel axis theorem we relate the moments of inertia of both plates and finally solve a very simple equation to find out the unknown parameter. This procedure avoids to calculate integrals. The result is extended to a scalene triangular plate by recognizing it is composed of two right triangular plates. We also review the parallel axis theorem in an appendix.
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spelling doaj.art-6732e70fb94d4fa3b88b4db67e5eed4b2022-12-21T19:27:49ZporSociedade Brasileira de FísicaRevista Brasileira de Ensino de Física1806-912641110.1590/1806-9126-rbef-2018-0146S1806-11172019000100801Moment of inertia through scaling and the parallel axis theoremRoberto RojasAbstract A right triangular plate scaled by a factor two generates a bigger plate composed of four triangular plates the same size as the original. By using dimensional analysis we write the moment of inertia around the center of mass, for the original and the bigger plate, in terms of a common unknown parameter. Through the parallel axis theorem we relate the moments of inertia of both plates and finally solve a very simple equation to find out the unknown parameter. This procedure avoids to calculate integrals. The result is extended to a scalene triangular plate by recognizing it is composed of two right triangular plates. We also review the parallel axis theorem in an appendix.http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1806-11172019000100801&lng=en&tlng=enMoment of inertiascalingparallel-axis theorem
spellingShingle Roberto Rojas
Moment of inertia through scaling and the parallel axis theorem
Revista Brasileira de Ensino de Física
Moment of inertia
scaling
parallel-axis theorem
title Moment of inertia through scaling and the parallel axis theorem
title_full Moment of inertia through scaling and the parallel axis theorem
title_fullStr Moment of inertia through scaling and the parallel axis theorem
title_full_unstemmed Moment of inertia through scaling and the parallel axis theorem
title_short Moment of inertia through scaling and the parallel axis theorem
title_sort moment of inertia through scaling and the parallel axis theorem
topic Moment of inertia
scaling
parallel-axis theorem
url http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1806-11172019000100801&lng=en&tlng=en
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