{"id":448,"date":"2022-03-17T22:50:16","date_gmt":"2022-03-17T22:50:16","guid":{"rendered":"https:\/\/2022.robocupjunior.eu\/rcj\/?page_id=448"},"modified":"2022-05-31T19:12:56","modified_gmt":"2022-05-31T19:12:56","slug":"ofi-46-pulley-systems","status":"publish","type":"page","link":"https:\/\/2022.robocupjunior.eu\/rcj\/index.php\/workshops\/mechanics\/ofi-46-pulley-systems\/","title":{"rendered":"Pulley Systems"},"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_1569d6e5a9b987358_ecclevel\" value=\"L\" \/><input type=\"hidden\" id=\"wpkqcg_qrcode_outputimg_1569d6e5a9b987358_size\" value=\"\" \/><input type=\"hidden\" id=\"wpkqcg_qrcode_outputimg_1569d6e5a9b987358_color\" value=\"\" \/><input type=\"hidden\" id=\"wpkqcg_qrcode_outputimg_1569d6e5a9b987358_bgcolor\" value=\"\" \/><input type=\"hidden\" id=\"wpkqcg_qrcode_outputimg_1569d6e5a9b987358_content\" value=\"https:\/\/2022.robocupjunior.eu\/rcj\/index.php\/wp-json\/wp\/v2\/pages\/448\" \/><img decoding=\"async\" src=\"\" id=\"wpkqcg_qrcode_outputimg_1569d6e5a9b987358\" 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\">Pulley Systems<\/h2>\n\n\n<p>Pulleys are a simple and manoeuvrable method of transporting huge goods. They are simple to move and set up when they are needed, but they do require a stable place to hang.<\/p>\n\n\n\n<p><strong>Components:<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>pulleys<\/li><li>ropes<\/li><li>weight<\/li><li>support<\/li><\/ul>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"Working-Principle:\">Working Principle:<\/h2>\n\n\n\n<p>Pulleys, like levers, use mechanical advantage to raise loads. Pulleys are wheel-shaped with a groove in the centre that allows a cord to pass through. To increase the amount of weight that can be lifted, they can be utilised by hand or coupled with a motorised winch.<\/p>\n\n\n\n<p><strong>Mechanical advantage<\/strong><\/p>\n\n\n\n<p>The mechanical advantage is a measure of the force amplification given by the use of a mechanical tool or system. In other words it is the ratio of the force produced by a machine relative to the force applied to it, used in assessing the performance of a machine.<\/p>\n\n\n\n<p><strong>Tensions in a Pulley<\/strong><\/p>\n\n\n\n<p>In a pulley the tension on both sides of the rope is the same (T<sub>2<\/sub>). The tension T<sub>1<\/sub> applied to the string that attaches the pulley to the ceiling in the picture below has to be the double of T<sub>2 <\/sub>(negleting the weigh of the pulley).<\/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>Chaging direction<\/strong><\/p>\n\n\n\n<p>Pulling down is easier than pushing up and, to achieve that, you can use a single pulley to reverse the direction of force. Cranes, lifting a bucket from a well, hoisting a flag, and changing window curtains all use single pulley systems.<\/p>\n\n\n\n<p>One pulley is referred to as having a mechanical advantage of one (MA = 1) even though there is no actual mechanical advantage. It\u2019s purpose is to change direction only.<\/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>Because the same amount of force is required, one pulley does not provide an actual mechanical advantage.<\/p>\n\n\n\n<p><strong>Simple Pulley System<\/strong><\/p>\n\n\n\n<p>If more pulleys are added, however, a mechanical advantage is generated. When you combine two pulleys, you just need half the force to lift. A block and tackle is a technique for lifting large, awkwardly shaped things, such as furniture. The load that the block and tackle can lift is increased by adding more wheels. With a movable pulley the mechanical advantage is two (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>Simple Pulley System 3:1<\/figcaption><\/figure>\n\n\n\n<p><strong>Compound Pulley System<\/strong><\/p>\n\n\n\n<p>When many simple pulley systems are piled together, a compound pulley system is formed. In the illustration, two systems \u2014 simple and compound \u2014 with the same MA = 8 are depicted. The mechanical advantages of all integrated simple systems are doubled in a compound pulley system. Their mechanical advantage, in other words, is characterised as<\/p>\n\n\n\n<p class=\"has-text-align-center\"><strong>MA = 2<sup>n<\/sup><\/strong><\/p>\n\n\n\n<p>The number of moving pulleys is denoted by the letter n.<\/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>Compound Pulley System 8:1<\/figcaption><\/figure>\n\n\n\n<p>The total MA of three 2:1 systems combined, as illustrated in our example, is 8:1. When a simple pulley system is compared to a compound one with the same MA, we can see that the compound system has less pulleys. Because of the added friction, a simple system is less efficient.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"Instructions:\">Instructions:<\/h2>\n\n\n\n<ol class=\"wp-block-list\"><li>Try lifting the same weight using the different pulley systems available<\/li><li>Can you calculate the mechanical advantage for each one?<\/li><\/ol>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"Links:.1\">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>Pulleys are a simple and manoeuvrable method of transporting huge goods. They are simple to move and set up when they are needed, but they do require a stable place to hang. Components: pulleys ropes weight support Working Principle: Pulleys, like levers, use mechanical advantage to raise loads. Pulleys are wheel-shaped with a groove in [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":455,"parent":241,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-448","page","type-page","status-publish","has-post-thumbnail","hentry"],"_links":{"self":[{"href":"https:\/\/2022.robocupjunior.eu\/rcj\/index.php\/wp-json\/wp\/v2\/pages\/448","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=448"}],"version-history":[{"count":5,"href":"https:\/\/2022.robocupjunior.eu\/rcj\/index.php\/wp-json\/wp\/v2\/pages\/448\/revisions"}],"predecessor-version":[{"id":982,"href":"https:\/\/2022.robocupjunior.eu\/rcj\/index.php\/wp-json\/wp\/v2\/pages\/448\/revisions\/982"}],"up":[{"embeddable":true,"href":"https:\/\/2022.robocupjunior.eu\/rcj\/index.php\/wp-json\/wp\/v2\/pages\/241"}],"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=448"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}