{"id":231,"date":"2012-02-23T10:55:03","date_gmt":"2012-02-23T09:55:03","guid":{"rendered":"https:\/\/blogs.ua.es\/jjrr2011\/?p=231"},"modified":"2012-02-23T11:43:12","modified_gmt":"2012-02-23T10:43:12","slug":"tema-3","status":"publish","type":"post","link":"https:\/\/blogs.ua.es\/jjrr2011\/2012\/02\/23\/tema-3\/","title":{"rendered":"TEMA 3. Centres de gravetat de superf\u00edcies planes"},"content":{"rendered":"<p style=\"text-align: justify\">Una situaci\u00f3 freq\u00fcent en la pr\u00e0ctica arquitect\u00f2nica \u00e9s l&#8217;actuaci\u00f3 de <strong>sistemes de forces pes<\/strong> que actuen sobre un element estructural distribu\u00efdes discretament o en forma cont\u00ednua. Aquest \u00e9s un cas particular de<strong> sistema de vectors lliscants paral\u00b7lels<\/strong> que es pot reduir a una resultant aplicada en el <strong>centre del sistema<\/strong>. El centre del sistema de forces pes l&#8217;anomenarem <strong>centre de gravetat G<\/strong>.<\/p>\n<p style=\"text-align: justify\">Per tant, en aquest cap\u00edtol s&#8217;aprendr\u00e0 a calcular centres de gravetat de cossos lineals, bidimensionals i tridimensionals. Com a cas particular, s&#8217;aprendr\u00e0 a calcular <strong>centres de gravetat de superf\u00edcies complexes<\/strong>.<\/p>\n<p style=\"text-align: justify\">Finalment, coneixerem i utilitzarem els <strong>teoremes de Pappos-Guldin<\/strong> que relacionen el centre de gravetat d&#8217;una l\u00ednia o una superf\u00edcie amb la superf\u00edcie lateral o el volum del cos de revoluci\u00f3 que generen en girar al voltant d&#8217;un eix donat.<\/p>\n<p style=\"text-align: justify\">En el <strong>laboratori de f\u00edsica<\/strong> es posar\u00e0 en pr\u00e0ctica els coneixements te\u00f2rics d&#8217;aquest cap\u00edtol per tal de <strong>calcular<\/strong> per dos m\u00e8todes diferents el <strong>centre de gravetat d&#8217;una superf\u00edcie plana<\/strong> amb una forma <strong>irregular<\/strong>.<\/p>\n<p style=\"text-align: justify\">Un document amb un resum del bloc tem\u00e0tic de geometria de masses es pot descarregar des de l&#8217;adre\u00e7a electr\u00f2nica del Repositori Institucional de la Universitat d&#8217;Alacant: <a href=\"http:\/\/rua.ua.es\/dspace\/handle\/10045\/19107\">http:\/\/rua.ua.es\/dspace\/handle\/10045\/19107<\/a>. Podeu consultar la presentaci\u00f3 corresponent a la sessi\u00f3 de teoria de centres de gravetat en l&#8217;adre\u00e7a electr\u00f2nica <a href=\"http:\/\/hdl.handle.net\/10045\/20716\">http:\/\/hdl.handle.net\/10045\/20716<\/a>.<\/p>\n<p style=\"text-align: justify\">Aquest v\u00eddeo realitzat per educa-Xile mostra una experi\u00e8ncia on s&#8217;expliquen els conceptes de centre de gravetat, for\u00e7a de fricci\u00f3 est\u00e0tica i din\u00e0mica.<\/p>\n<p><code>[kml_flashembed movie=\"http:\/\/www.youtube.com\/v\/xM9rZj2qQkc\" width=\"396\" height=\"297\" wmode=\"transparent\" \/]<\/code><\/p>\n<p style=\"text-align: justify\"><strong>Bibliografia<\/strong><\/p>\n<p style=\"text-align: justify\">Rodes Roca, J. J., Dur\u00e1 Dom\u00e9nech, A. i Vera Guarinos, J., <em>Fonaments f\u00edsics de les construccions arquitect\u00f2niques<\/em> (Publicacions de la Universitat d&#8217;Alacant, Alacant, 2011). Cap\u00edtol 4.<\/p>\n<p style=\"text-align: justify\">Rodes Roca, J. J., <em>Exercicis i problemes dels fonaments f\u00edsics d&#8217;arquitectura. I. Vectors lliscants i geometria de masses<\/em> (ECU, Alacant, 2009)<\/p>\n<p style=\"text-align: justify\">Tipler, P. A. i Mosca, G., F\u00edsica per a la ci\u00e8ncia i la tecnologia, Volum 1 (Revert\u00e9, Barcelona, 2010). Cap\u00edtols 1 i 12.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Una situaci\u00f3 freq\u00fcent en la pr\u00e0ctica arquitect\u00f2nica \u00e9s l&#8217;actuaci\u00f3 de sistemes de forces pes que actuen sobre un element estructural distribu\u00efdes discretament o en forma cont\u00ednua. Aquest \u00e9s un cas particular de sistema de vectors lliscants paral\u00b7lels que es pot reduir a una resultant aplicada en el centre del sistema. El centre del sistema de [&hellip;]<\/p>\n","protected":false},"author":2285,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[82858,82859,676],"tags":[82856,135912,82857,91078],"class_list":["post-231","post","type-post","status-publish","format-standard","hentry","category-assignatura-2","category-objectius","category-sin-categoria","tag-assignatura","tag-ensenyament-aprenentatge","tag-grau","tag-materials"],"_links":{"self":[{"href":"https:\/\/blogs.ua.es\/jjrr2011\/wp-json\/wp\/v2\/posts\/231","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.ua.es\/jjrr2011\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.ua.es\/jjrr2011\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.ua.es\/jjrr2011\/wp-json\/wp\/v2\/users\/2285"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.ua.es\/jjrr2011\/wp-json\/wp\/v2\/comments?post=231"}],"version-history":[{"count":8,"href":"https:\/\/blogs.ua.es\/jjrr2011\/wp-json\/wp\/v2\/posts\/231\/revisions"}],"predecessor-version":[{"id":236,"href":"https:\/\/blogs.ua.es\/jjrr2011\/wp-json\/wp\/v2\/posts\/231\/revisions\/236"}],"wp:attachment":[{"href":"https:\/\/blogs.ua.es\/jjrr2011\/wp-json\/wp\/v2\/media?parent=231"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.ua.es\/jjrr2011\/wp-json\/wp\/v2\/categories?post=231"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.ua.es\/jjrr2011\/wp-json\/wp\/v2\/tags?post=231"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}