{"id":161,"date":"2018-03-17T14:47:27","date_gmt":"2018-03-17T14:47:27","guid":{"rendered":"https:\/\/books.compclassnotes.com\/rothphys110\/?p=161"},"modified":"2021-04-28T16:40:56","modified_gmt":"2021-04-28T16:40:56","slug":"section-6-3","status":"publish","type":"post","link":"https:\/\/books.compclassnotes.com\/rothphys110-2e\/2018\/03\/17\/section-6-3\/","title":{"rendered":"Chapter 6: Energy"},"content":{"rendered":"\n<h2 class=\"wp-block-heading\">6.3 Kinetic energy<\/h2>\n\n\n\n<p>The energy associated with motion is called&nbsp;<em>kinetic energy<\/em>. Since there are two kinds of motion (translational and rotational), there are two kinds of kinetic energy.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">6.3.1 Translational kinetic energy<\/h3>\n\n\n\n<p>For an object with a mass <em>m<\/em>, traveling in a straight line with a speed <em>v<\/em> (we generally drop the absolute value signs for convenience when working with energy), the kinetic energy is given by the expression<\/p>\n\n\n\n<p align=\"center\"><em>K<\/em> = <sup>1<\/sup>\u2044<sub>2<\/sub><em>m<\/em><em>v<sup>2<\/sup><\/em><\/p>\n\n\n\n<p>From this expression, we see how to express the joule in base SI units: 1 J = 1 kg \u00b7 m\/s<sup>2<\/sup><\/p>\n\n\n\n<p id=\"return1\">Remember, speed is the magnitude of velocity. This means energy is a scalar quantity. Kinetic energy is not associated with any particular direction of motion,<sup><a href=\"#note1\">*<\/a><\/sup>&nbsp;only how fast the object is going.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">Practice<\/h4>\n\n\n\n<!-- iframe plugin v.6.0 wordpress.org\/plugins\/iframe\/ -->\n<iframe loading=\"lazy\" src=\"https:\/\/my.compclassnotes.com\/canonical\/PHYS110\/PHYS110_book_ch6v2_prac1_v2\" width=\"100%\" height=\"600\" marginwidth=\"0\" marginheight=\"0\" scrolling=\"yes\" class=\"iframe-class\" frameborder=\"0\"><\/iframe>\n\n\n\n\n<h3 class=\"wp-block-heading\">6.3.2 Rotational kinetic energy<\/h3>\n\n\n\n<!-- iframe plugin v.6.0 wordpress.org\/plugins\/iframe\/ -->\n<iframe loading=\"lazy\" src=\"https:\/\/my.compclassnotes.com\/canonical\/PHYS110\/PHYS110_book_ch_6_3_2\" width=\"100%\" height=\"1000\" marginwidth=\"0\" marginheight=\"0\" scrolling=\"yes\" class=\"iframe-class\" frameborder=\"0\"><\/iframe>\n\n\n\n\n<p>The following table lists the moment of inertia of several common objects. The column labeled &#8220;type of motion&#8221; is a sort of generalization, to describe how the object is rotating. For example, if the type of motion is &#8220;rolling,&#8221; visualize the object spinning around a central axis as if it were wheel. An object rotating like this may be spinning in place, or rolling forward, but the moment of inertia would be the same&#8211;the moment of inertia depends on the shape of the object and its axis of rotation.<\/p>\n\n\n\n<p>For a specific example, a disk (which is simply a very short cylinder) that is rolling forward would have the same moment of inertia as a disk that is acting as a pulley and rotating in place. However, if the disk is flipping end-over-end, like you would flip a coin, the moment of inertia would be different.<\/p>\n\n\n\n<!-- iframe plugin v.6.0 wordpress.org\/plugins\/iframe\/ -->\n<iframe loading=\"lazy\" src=\"https:\/\/my.compclassnotes.com\/canonical\/PHYS110\/PHYS110_book_ch_6_1_table\" width=\"100%\" height=\"1400\" marginwidth=\"0\" marginheight=\"0\" scrolling=\"yes\" class=\"iframe-class\" frameborder=\"0\"><\/iframe>\n\n\n\n\n<h4 class=\"wp-block-heading\">Practice<\/h4>\n\n\n\n<p>In this problem you&#8217;ll need to consider how an object&#8217;s mass distribution affects its moment of inertia.<\/p>\n\n\n\n<!-- iframe plugin v.6.0 wordpress.org\/plugins\/iframe\/ -->\n<iframe loading=\"lazy\" src=\"https:\/\/my.compclassnotes.com\/canonical\/PHYS110\/PHYS110_book_ch8_prac_q8\" width=\"100%\" height=\"600\" marginwidth=\"0\" marginheight=\"0\" scrolling=\"yes\" class=\"iframe-class\" frameborder=\"0\"><\/iframe>\n\n\n\n\n<p id=\"note1\"><sup><a href=\"#return1\">*<\/a><\/sup>This is one of the limitations of energy analysis. Just like any tool, it is not necessarily the best for every situation.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>6.3 Kinetic energy The energy associated with motion is called&nbsp;kinetic energy. Since there are two kinds of motion (translational and rotational), there are two kinds of kinetic energy. 6.3.1 Translational kinetic energy For an object with a mass m, traveling <span class=\"readmore\"><a href=\"https:\/\/books.compclassnotes.com\/rothphys110-2e\/2018\/03\/17\/section-6-3\/\">Continue Reading<\/a><\/span><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-161","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/books.compclassnotes.com\/rothphys110-2e\/wp-json\/wp\/v2\/posts\/161","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/books.compclassnotes.com\/rothphys110-2e\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/books.compclassnotes.com\/rothphys110-2e\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/books.compclassnotes.com\/rothphys110-2e\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/books.compclassnotes.com\/rothphys110-2e\/wp-json\/wp\/v2\/comments?post=161"}],"version-history":[{"count":8,"href":"https:\/\/books.compclassnotes.com\/rothphys110-2e\/wp-json\/wp\/v2\/posts\/161\/revisions"}],"predecessor-version":[{"id":855,"href":"https:\/\/books.compclassnotes.com\/rothphys110-2e\/wp-json\/wp\/v2\/posts\/161\/revisions\/855"}],"wp:attachment":[{"href":"https:\/\/books.compclassnotes.com\/rothphys110-2e\/wp-json\/wp\/v2\/media?parent=161"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/books.compclassnotes.com\/rothphys110-2e\/wp-json\/wp\/v2\/categories?post=161"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/books.compclassnotes.com\/rothphys110-2e\/wp-json\/wp\/v2\/tags?post=161"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}