{"id":560,"date":"2016-10-17T07:29:28","date_gmt":"2016-10-17T07:29:28","guid":{"rendered":"https:\/\/blogs.ua.es\/ffic\/?p=560"},"modified":"2016-10-14T07:36:07","modified_gmt":"2016-10-14T07:36:07","slug":"chapter-3-3rd","status":"publish","type":"post","link":"https:\/\/blogs.ua.es\/ffic\/2016\/10\/17\/chapter-3-3rd\/","title":{"rendered":"Chapter 3. Thermodynamics (III)"},"content":{"rendered":"<p style=\"text-align: justify\"><span style=\"color: #b03704\"><strong>Raymond A. Serway and John W. Jewett. &#8220;<em>Physics for Scientists and Engineers with modern physics<\/em>&#8220;, 8th edition, Brooks\/Cole, Belmont, USA (2010)<br \/>\n<\/strong><\/span><\/p>\n<p style=\"text-align: justify\"><span style=\"color: #b03704\"><strong>Part 3. Thermodynamics<\/strong><\/span><\/p>\n<p style=\"text-align: justify\"><strong><span style=\"color: #800080\">HEAT ENGINES, ENTROPY AND THE SECOND LAW OF THERMODYNAMICS<br \/>\n<\/span><\/strong><\/p>\n<p style=\"text-align: justify\">The first law of thermodynamics, which we studied in the first session, is a statement of conservation of energy and is a special-case reduction of Equation 8.2. This law states that a change in internal energy in a system can occur as a result of <strong><span style=\"color: #ff00ff\">energy transfer<\/span><\/strong> by <strong><span style=\"color: #333399\">heat<\/span><\/strong>, by <strong><span style=\"color: #333399\">work<\/span><\/strong>, or by <strong><span style=\"color: #333399\">both<\/span><\/strong>. Although the first law of thermodynamics is very important, it makes no distinction between processes that occur spontaneously and those that do not. Only <span style=\"color: #ff0000\"><strong>certain types<\/strong><\/span> of energy conversion and energy transfer processes actually <span style=\"color: #333399\"><strong>take place in nature<\/strong><\/span>, however. The <strong>second law of thermodynamics<\/strong>, the major topic in this chapter, <strong><span style=\"color: #ff0000\">establishes<\/span><\/strong> which <strong><span style=\"color: #ff00ff\">processes do and do not occur<\/span><\/strong>. The following are examples of <strong><span style=\"color: #333399\">processes<\/span><\/strong> that do not violate the first law of thermodynamics if they proceed in either direction, but are <strong><span style=\"color: #ff00ff\">observed in reality to proceed in only one direction<\/span><\/strong>:<\/p>\n<ul>\n<li style=\"text-align: justify\">When <strong><span style=\"color: #333399\">two objects at different temperatures<\/span><\/strong> are placed <strong><span style=\"color: #ff0000\">in thermal contact<\/span><\/strong> with each other, the net <strong><span style=\"color: #333399\">transfer of energy<\/span><\/strong> by heat is <strong><span style=\"color: #ff00ff\">always<\/span> <span style=\"color: #ff0000\">from the warmer object<\/span> <span style=\"color: #ff0000\">to the cooler object<\/span><\/strong>, never from the cooler to the warmer.<\/li>\n<li style=\"text-align: justify\">A <strong><span style=\"color: #333399\">rubber ball dropped to the ground bounces<\/span><\/strong> several times and eventually comes to rest, but a ball lying on the ground never gathers internal energy from the ground and begins bouncing on its own.<\/li>\n<li style=\"text-align: justify\">An <strong><span style=\"color: #333399\">oscillating pendulum<\/span><\/strong> eventually comes to rest because of collisions with air molecules and friction at the point of suspension. The mechanical energy of the system is converted to internal energy in the air, the pendulum, and the suspension; the reverse conversion of energy never occurs.<\/li>\n<\/ul>\n<p style=\"text-align: justify\">All these <strong><span style=\"color: #333399\">processes<\/span><\/strong> are <strong><span style=\"color: #ff0000\">irreversible<\/span><\/strong>; that is, they are processes that occur naturally in one direction only. No irreversible process has ever been observed to run backward. If it were to do so, it would violate the second law of thermodynamics.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Raymond A. Serway and John W. Jewett. &#8220;Physics for Scientists and Engineers with modern physics&#8220;, 8th edition, Brooks\/Cole, Belmont, USA (2010) Part 3. Thermodynamics HEAT ENGINES, ENTROPY AND THE SECOND LAW OF THERMODYNAMICS The first law of thermodynamics, which we &hellip; <a href=\"https:\/\/blogs.ua.es\/ffic\/2016\/10\/17\/chapter-3-3rd\/\">Continue reading <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":2285,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[135920,9333],"tags":[9337],"class_list":["post-560","post","type-post","status-publish","format-standard","hentry","category-aims","category-subject","tag-teaching-learning"],"_links":{"self":[{"href":"https:\/\/blogs.ua.es\/ffic\/wp-json\/wp\/v2\/posts\/560","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.ua.es\/ffic\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.ua.es\/ffic\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.ua.es\/ffic\/wp-json\/wp\/v2\/users\/2285"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.ua.es\/ffic\/wp-json\/wp\/v2\/comments?post=560"}],"version-history":[{"count":3,"href":"https:\/\/blogs.ua.es\/ffic\/wp-json\/wp\/v2\/posts\/560\/revisions"}],"predecessor-version":[{"id":590,"href":"https:\/\/blogs.ua.es\/ffic\/wp-json\/wp\/v2\/posts\/560\/revisions\/590"}],"wp:attachment":[{"href":"https:\/\/blogs.ua.es\/ffic\/wp-json\/wp\/v2\/media?parent=560"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.ua.es\/ffic\/wp-json\/wp\/v2\/categories?post=560"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.ua.es\/ffic\/wp-json\/wp\/v2\/tags?post=560"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}