{"id":457,"date":"2022-03-17T22:54:42","date_gmt":"2022-03-17T22:54:42","guid":{"rendered":"https:\/\/2022.robocupjunior.eu\/rcj\/?page_id=457"},"modified":"2022-06-27T15:15:27","modified_gmt":"2022-06-27T15:15:27","slug":"ofi-46-sistemas-de-roldanas","status":"publish","type":"page","link":"https:\/\/2022.robocupjunior.eu\/rcj\/index.php\/oficinas\/mecanica\/ofi-46-sistemas-de-roldanas\/","title":{"rendered":"Sistemas de Roldanas"},"content":{"rendered":"\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-is-layout-28f84493 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\" style=\"flex-basis:80%\"><figure class=\"wp-block-post-featured-image\"><img loading=\"lazy\" decoding=\"async\" width=\"890\" height=\"832\" src=\"https:\/\/2022.robocupjunior.eu\/rcj\/wp-content\/uploads\/2022\/03\/Pulley_1_3_small2.png\" class=\"attachment-post-thumbnail size-post-thumbnail wp-post-image\" alt=\"\" style=\"object-fit:cover;\" srcset=\"https:\/\/2022.robocupjunior.eu\/rcj\/wp-content\/uploads\/2022\/03\/Pulley_1_3_small2.png 890w, https:\/\/2022.robocupjunior.eu\/rcj\/wp-content\/uploads\/2022\/03\/Pulley_1_3_small2-300x280.png 300w, https:\/\/2022.robocupjunior.eu\/rcj\/wp-content\/uploads\/2022\/03\/Pulley_1_3_small2-768x718.png 768w\" sizes=\"auto, (max-width: 890px) 100vw, 890px\" \/><\/figure><\/div>\n\n\n\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\" style=\"padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;flex-basis:20%\">\n<!-- START Kaya QR Code Generator --><div class=\"wpkqcg_qrcode_wrapper\"><input type=\"hidden\" id=\"wpkqcg_qrcode_outputimg_6569d6e62c8107858_ecclevel\" value=\"L\" \/><input type=\"hidden\" id=\"wpkqcg_qrcode_outputimg_6569d6e62c8107858_size\" value=\"\" \/><input type=\"hidden\" id=\"wpkqcg_qrcode_outputimg_6569d6e62c8107858_color\" value=\"\" \/><input type=\"hidden\" id=\"wpkqcg_qrcode_outputimg_6569d6e62c8107858_bgcolor\" value=\"\" \/><input type=\"hidden\" id=\"wpkqcg_qrcode_outputimg_6569d6e62c8107858_content\" value=\"https:\/\/2022.robocupjunior.eu\/rcj\/index.php\/wp-json\/wp\/v2\/pages\/457\" \/><img decoding=\"async\" src=\"\" id=\"wpkqcg_qrcode_outputimg_6569d6e62c8107858\" alt=\"QR Code\" class=\"wpkqcg_qrcode\" style=\"width: auto; height: auto; max-width: 100%;\" ><div style=\"clear: none;\"><\/div><\/div><!-- END Kaya QR Code Generator -->\n<\/div>\n<\/div>\n\n\n<h2 class=\"wp-block-post-title\">Sistemas de Roldanas<\/h2>\n\n\n<figure class=\"wp-block-embed is-type-video is-provider-youtube wp-block-embed-youtube wp-embed-aspect-16-9 wp-has-aspect-ratio\"><div class=\"wp-block-embed__wrapper\">\n<iframe loading=\"lazy\" title=\"Sistema de Roldanas\" width=\"500\" height=\"281\" src=\"https:\/\/www.youtube.com\/embed\/PWmJQOvP1d8?feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" referrerpolicy=\"strict-origin-when-cross-origin\" allowfullscreen><\/iframe>\n<\/div><\/figure>\n\n\n\n<p>Os sistemas roldanas s\u00e3o um m\u00e9todo simples e manobr\u00e1vel muito usado em transporte de mercadorias pesadas. S\u00e3o simples de mover e de montar quando s\u00e3o necess\u00e1rias, mas requerem um lugar est\u00e1vel para serem penduradas.<\/p>\n\n\n\n<p><strong>Componentes:<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>roldanas<\/li><li>cordas<\/li><li>peso<\/li><li>apoio<\/li><\/ul>\n\n\n\n<p><strong>Princ\u00edpio de funcionamento:<\/strong><\/p>\n\n\n\n<p>As roldanas, tal como as alavancas, utilizam a vantagem mec\u00e2nica para levantar cargas. As roldanas s\u00e3o em forma de roda com uma ranhura no centro que permite a passagem de um cord\u00e3o. Para aumentar a quantidade de peso que pode ser levantada, podem ser utilizadas \u00e0 m\u00e3o ou acopladas a um guincho motorizado.<\/p>\n\n\n\n<p><strong>Vantagem mec\u00e2nica<\/strong><\/p>\n\n\n\n<p>A vantagem mec\u00e2nica \u00e9 uma medida da amplifica\u00e7\u00e3o da for\u00e7a dada pela utiliza\u00e7\u00e3o de uma ferramenta ou sistema mec\u00e2nico. Por outras palavras, \u00e9 a raz\u00e3o entre a for\u00e7a produzida por uma m\u00e1quina e a for\u00e7a aplicada \u00e0 mesma, utilizada na avalia\u00e7\u00e3o do desempenho de uma m\u00e1quina.<\/p>\n\n\n\n<p><strong>Tens\u00f5es numa roldana<\/strong><\/p>\n\n\n\n<p>Numa roldana, a tens\u00e3o em ambos os lados da corda \u00e9 a mesma (T2). A tens\u00e3o T1 aplicada \u00e0 corda que prende a roldana ao tecto na figura abaixo tem de ser o dobro de T2 (desprezando o peso da roldana).<\/p>\n\n\n\n<figure class=\"wp-block-image aligncenter size-large is-resized\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/2022.robocupjunior.eu\/rcj\/wp-content\/uploads\/2022\/03\/pulley_Tensions-1024x982.png\" alt=\"\" class=\"wp-image-452\" width=\"512\" height=\"491\" srcset=\"https:\/\/2022.robocupjunior.eu\/rcj\/wp-content\/uploads\/2022\/03\/pulley_Tensions-1024x982.png 1024w, https:\/\/2022.robocupjunior.eu\/rcj\/wp-content\/uploads\/2022\/03\/pulley_Tensions-300x288.png 300w, https:\/\/2022.robocupjunior.eu\/rcj\/wp-content\/uploads\/2022\/03\/pulley_Tensions-768x737.png 768w, https:\/\/2022.robocupjunior.eu\/rcj\/wp-content\/uploads\/2022\/03\/pulley_Tensions.png 1122w\" sizes=\"auto, (max-width: 512px) 100vw, 512px\" \/><\/figure>\n\n\n\n<p><strong>Mudan\u00e7a de direc\u00e7\u00e3o<\/strong><\/p>\n\n\n\n<p>Puxar para baixo \u00e9 mais f\u00e1cil do que empurrar para cima e, para o conseguir, pode usar uma \u00fanica roldana para inverter a direc\u00e7\u00e3o da for\u00e7a. V\u00e1rios sistemas usam uma \u00fanica roldana, como por exemplo, gruas, roldanas para levantar um balde de um po\u00e7o, i\u00e7ar uma bandeira, e mudar as cortinas das janelas.<\/p>\n\n\n\n<p>Uma roldana s\u00f3 tem uma vantagem mec\u00e2nica de um (MA = 1). Embora n\u00e3o haja uma vantagem mec\u00e2nica real, o seu objectivo \u00e9 facilitar a mudan\u00e7a de direc\u00e7\u00e3o.<\/p>\n\n\n\n<figure class=\"wp-block-image aligncenter size-large is-resized\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/2022.robocupjunior.eu\/rcj\/wp-content\/uploads\/2022\/03\/Pulley_cd-655x1024.png\" alt=\"\" class=\"wp-image-451\" width=\"328\" height=\"512\" srcset=\"https:\/\/2022.robocupjunior.eu\/rcj\/wp-content\/uploads\/2022\/03\/Pulley_cd-655x1024.png 655w, https:\/\/2022.robocupjunior.eu\/rcj\/wp-content\/uploads\/2022\/03\/Pulley_cd-192x300.png 192w, https:\/\/2022.robocupjunior.eu\/rcj\/wp-content\/uploads\/2022\/03\/Pulley_cd-768x1202.png 768w, https:\/\/2022.robocupjunior.eu\/rcj\/wp-content\/uploads\/2022\/03\/Pulley_cd.png 891w\" sizes=\"auto, (max-width: 328px) 100vw, 328px\" \/><\/figure>\n\n\n\n<p>Como \u00e9 necess\u00e1ria a mesma quantidade de for\u00e7a, uma roldana n\u00e3o proporciona uma vantagem mec\u00e2nica real.<\/p>\n\n\n\n<p><strong>Sistema de roldanas simples<\/strong><\/p>\n\n\n\n<p>No entanto, se forem acrescentadas mais roldanas, \u00e9 gerada uma vantagem mec\u00e2nica. Quando se combinam duas roldanas, s\u00f3 \u00e9 preciso metade da for\u00e7a para levantar. Sistemas de roldanas s\u00e3o muitas vezes usados para elevar objetos grandes e pesados, tais como mobili\u00e1rio. A carga que o sistema pode levantar \u00e9 aumentada atrav\u00e9s da adi\u00e7\u00e3o de mais rodas. Com uma roldana m\u00f3vel a vantagem mec\u00e2nica \u00e9 de dois (MA = 2).<\/p>\n\n\n\n<figure class=\"wp-block-image aligncenter size-large is-resized\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/2022.robocupjunior.eu\/rcj\/wp-content\/uploads\/2022\/03\/Pulley_1_3-706x1024.png\" alt=\"\" class=\"wp-image-449\" width=\"353\" height=\"512\" srcset=\"https:\/\/2022.robocupjunior.eu\/rcj\/wp-content\/uploads\/2022\/03\/Pulley_1_3-706x1024.png 706w, https:\/\/2022.robocupjunior.eu\/rcj\/wp-content\/uploads\/2022\/03\/Pulley_1_3-207x300.png 207w, https:\/\/2022.robocupjunior.eu\/rcj\/wp-content\/uploads\/2022\/03\/Pulley_1_3-768x1114.png 768w, https:\/\/2022.robocupjunior.eu\/rcj\/wp-content\/uploads\/2022\/03\/Pulley_1_3-1059x1536.png 1059w, https:\/\/2022.robocupjunior.eu\/rcj\/wp-content\/uploads\/2022\/03\/Pulley_1_3.png 1305w\" sizes=\"auto, (max-width: 353px) 100vw, 353px\" \/><figcaption>Sistema simples 3:1<\/figcaption><\/figure>\n\n\n\n<p><strong>Sistema de roldanas compostas<\/strong><\/p>\n\n\n\n<p>Quando se combina v\u00e1rios sistemas de roldanas simples, forma-se um sistema de roldanas composto. Na ilustra\u00e7\u00e3o, dois sistemas &#8211; simples e composto &#8211; com o mesmo MA = 8 s\u00e3o representados. As vantagens mec\u00e2nicas de todos os sistemas simples integrados s\u00e3o duplicadas num sistema de roldanas compostas. A sua vantagem mec\u00e2nica, por outras palavras, \u00e9 caracterizada como<\/p>\n\n\n\n<p class=\"has-text-align-center\"><strong>MA = 2<sup>n<\/sup><\/strong><\/p>\n\n\n\n<p>O n\u00famero de roldanas em movimento \u00e9 assinalado pela letra n.  Note-se que a ultima roldana (\u00e0 direita) n\u00e3o \u00e9 considerada pois serve apenas para inverter a dire\u00e7\u00e3o.<\/p>\n\n\n\n<figure class=\"wp-block-image aligncenter size-large is-resized\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/2022.robocupjunior.eu\/rcj\/wp-content\/uploads\/2022\/03\/Pulley_1_8-572x1024.png\" alt=\"\" class=\"wp-image-450\" width=\"286\" height=\"512\" srcset=\"https:\/\/2022.robocupjunior.eu\/rcj\/wp-content\/uploads\/2022\/03\/Pulley_1_8-572x1024.png 572w, https:\/\/2022.robocupjunior.eu\/rcj\/wp-content\/uploads\/2022\/03\/Pulley_1_8-167x300.png 167w, https:\/\/2022.robocupjunior.eu\/rcj\/wp-content\/uploads\/2022\/03\/Pulley_1_8-768x1376.png 768w, https:\/\/2022.robocupjunior.eu\/rcj\/wp-content\/uploads\/2022\/03\/Pulley_1_8-857x1536.png 857w, https:\/\/2022.robocupjunior.eu\/rcj\/wp-content\/uploads\/2022\/03\/Pulley_1_8-1143x2048.png 1143w, https:\/\/2022.robocupjunior.eu\/rcj\/wp-content\/uploads\/2022\/03\/Pulley_1_8.png 1457w\" sizes=\"auto, (max-width: 286px) 100vw, 286px\" \/><figcaption>Sistema composto 8:1<\/figcaption><\/figure>\n\n\n\n<p>O MA total de tr\u00eas sistemas 2:1 combinados, como ilustrado no nosso exemplo, \u00e9 8:1. Quando um sistema de roldanas simples \u00e9 comparado com um sistema composto com o mesmo MA, podemos ver que o sistema composto tem menos roldanas. Devido \u00e0 fric\u00e7\u00e3o adicional, um sistema simples \u00e9 tamb\u00e9m menos eficiente.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"Instru\u00e7\u00f5es:\">Instru\u00e7\u00f5es:<\/h2>\n\n\n\n<ol class=\"wp-block-list\"><li>Tente levantar o mesmo peso utilizando os diferentes sistemas de roldanas dispon\u00edveis<\/li><li>Consegue calcular a vantagem mec\u00e2nica para cada um deles?<\/li><\/ol>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"Links:\">Links:<\/h2>\n\n\n\n<p><a href=\"https:\/\/www.youtube.com\/watch?v=rcURj0bQx98\">Simple pulley systems<\/a><\/p>\n\n\n\n<p><a href=\"https:\/\/www.youtube.com\/watch?v=M2w3NZzPwOM\">Why Snatch Blocks are AWESOME (How Pulleys Work) &#8211; Smarter Every Day 228<\/a><\/p>\n\n\n\n<p><a href=\"https:\/\/www.youtube.com\/watch?v=6GuldysCVjI\">Mechanical Engineering: Particle Equilibrium (11 of 19) Why are Pulleys a Mechanical Advantage?<\/a><\/p>\n\n\n\n<p><a href=\"https:\/\/www.bbc.co.uk\/bitesize\/guides\/z7gyb82\/revision\/3\">Pulley systems &#8211; Mechanical devices &#8211; Eduqas &#8211; GCSE Design and Technology Revision &#8211; Eduqas &#8211; BBC Bitesize<\/a><\/p>\n\n\n\n<p><a href=\"https:\/\/www.ropebook.com\/information\/pulley-systems\">Pulley Systems &#8211; ropebook<\/a><\/p>\n\n\n\n<p><a href=\"https:\/\/www.brighthubengineering.com\/machine-design\/121215-calculation-methods-for-pulley-systems\/\">How to Calculate First, Second and Third Pulley Systems<\/a><\/p>\n\n\n\n<p><a href=\"https:\/\/www.translatorscafe.com\/unit-converter\/en-US\/calculator\/pulley-mechanical-advantage\/\">System of Pulleys \u2014 Mechanical Advantage Calculator \u2022 Mechanics \u2022 Online Unit Converters<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Os sistemas roldanas s\u00e3o um m\u00e9todo simples e manobr\u00e1vel muito usado em transporte de mercadorias pesadas. S\u00e3o simples de mover e de montar quando s\u00e3o necess\u00e1rias, mas requerem um lugar est\u00e1vel para serem penduradas. Componentes: roldanas cordas peso apoio Princ\u00edpio de funcionamento: As roldanas, tal como as alavancas, utilizam a vantagem mec\u00e2nica para levantar cargas. [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":455,"parent":239,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-457","page","type-page","status-publish","has-post-thumbnail","hentry"],"_links":{"self":[{"href":"https:\/\/2022.robocupjunior.eu\/rcj\/index.php\/wp-json\/wp\/v2\/pages\/457","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/2022.robocupjunior.eu\/rcj\/index.php\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/2022.robocupjunior.eu\/rcj\/index.php\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/2022.robocupjunior.eu\/rcj\/index.php\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/2022.robocupjunior.eu\/rcj\/index.php\/wp-json\/wp\/v2\/comments?post=457"}],"version-history":[{"count":6,"href":"https:\/\/2022.robocupjunior.eu\/rcj\/index.php\/wp-json\/wp\/v2\/pages\/457\/revisions"}],"predecessor-version":[{"id":1030,"href":"https:\/\/2022.robocupjunior.eu\/rcj\/index.php\/wp-json\/wp\/v2\/pages\/457\/revisions\/1030"}],"up":[{"embeddable":true,"href":"https:\/\/2022.robocupjunior.eu\/rcj\/index.php\/wp-json\/wp\/v2\/pages\/239"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/2022.robocupjunior.eu\/rcj\/index.php\/wp-json\/wp\/v2\/media\/455"}],"wp:attachment":[{"href":"https:\/\/2022.robocupjunior.eu\/rcj\/index.php\/wp-json\/wp\/v2\/media?parent=457"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}