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		<title>Solution 9.4 - Revision history</title>
		<link>http://wiki.sommarmatte.se/wikis/2009/bridgecoursemechanics/index.php?title=Solution_9.4&amp;action=history</link>
		<description>Revision history for this page on the wiki</description>
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			<title>Ian at 11:11, 17 May 2010</title>
			<link>http://wiki.sommarmatte.se/wikis/2009/bridgecoursemechanics/index.php?title=Solution_9.4&amp;diff=1130&amp;oldid=prev</link>
			<description>&lt;p&gt;&lt;/p&gt;

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				&lt;td colspan='2' style=&quot;background-color: white; color:black;&quot;&gt;←Older revision&lt;/td&gt;
				&lt;td colspan='2' style=&quot;background-color: white; color:black;&quot;&gt;Revision as of 11:11, 17 May 2010&lt;/td&gt;
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		&lt;tr&gt;&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 19:&lt;/td&gt;
&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 19:&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt; &lt;/td&gt;&lt;td style=&quot;background: #eee; color:black; font-size: smaller;&quot;&gt;&lt;div&gt;&amp;lt;math&amp;gt;\uparrow :\quad  R-mg=0&amp;lt;/math&amp;gt;&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt; &lt;/td&gt;&lt;td style=&quot;background: #eee; color:black; font-size: smaller;&quot;&gt;&lt;div&gt;&amp;lt;math&amp;gt;\uparrow :\quad  R-mg=0&amp;lt;/math&amp;gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt; &lt;/td&gt;&lt;td style=&quot;background: #eee; color:black; font-size: smaller;&quot;&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt; &lt;/td&gt;&lt;td style=&quot;background: #eee; color:black; font-size: smaller;&quot;&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;-&lt;/td&gt;&lt;td style=&quot;background: #ffa; color:black; font-size: smaller;&quot;&gt;&lt;div&gt;&amp;lt;math&amp;gt;R=mg=4\times 9.81=39.24\ \text{N}&amp;lt;/math&amp;gt;&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;background: #cfc; color:black; font-size: smaller;&quot;&gt;&lt;div&gt;&amp;lt;math&amp;gt;R=mg=4\times 9&lt;ins style=&quot;color: red; font-weight: bold; text-decoration: none;&quot;&gt;\textrm{&lt;/ins&gt;.&lt;ins style=&quot;color: red; font-weight: bold; text-decoration: none;&quot;&gt;}&lt;/ins&gt;81=39&lt;ins style=&quot;color: red; font-weight: bold; text-decoration: none;&quot;&gt;\textrm{&lt;/ins&gt;.&lt;ins style=&quot;color: red; font-weight: bold; text-decoration: none;&quot;&gt;}&lt;/ins&gt;24\ \text{N}&lt;ins style=&quot;color: red; font-weight: bold; text-decoration: none;&quot;&gt;&amp;lt;/math&amp;gt;&lt;/ins&gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td colspan=&quot;2&quot;&gt;&amp;nbsp;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;background: #cfc; color:black; font-size: smaller;&quot;&gt;&lt;div&gt;&amp;#160;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td colspan=&quot;2&quot;&gt;&amp;nbsp;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;background: #cfc; color:black; font-size: smaller;&quot;&gt;&lt;div&gt;&lt;ins style=&quot;color: red; font-weight: bold; text-decoration: none;&quot;&gt;Substituting in the friction equation,&lt;/ins&gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td colspan=&quot;2&quot;&gt;&amp;nbsp;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;background: #cfc; color:black; font-size: smaller;&quot;&gt;&lt;div&gt;&amp;#160;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td colspan=&quot;2&quot;&gt;&amp;nbsp;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;background: #cfc; color:black; font-size: smaller;&quot;&gt;&lt;div&gt;&lt;ins style=&quot;color: red; font-weight: bold; text-decoration: none;&quot;&gt;&amp;lt;math&amp;gt;20 = \mu \times 39\textrm{.}24&amp;lt;/math&amp;gt;&lt;/ins&gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td colspan=&quot;2&quot;&gt;&amp;nbsp;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;background: #cfc; color:black; font-size: smaller;&quot;&gt;&lt;div&gt;&amp;#160;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td colspan=&quot;2&quot;&gt;&amp;nbsp;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;background: #cfc; color:black; font-size: smaller;&quot;&gt;&lt;div&gt;&lt;ins style=&quot;color: red; font-weight: bold; text-decoration: none;&quot;&gt;giving&lt;/ins&gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td colspan=&quot;2&quot;&gt;&amp;nbsp;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;background: #cfc; color:black; font-size: smaller;&quot;&gt;&lt;div&gt;&amp;#160;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td colspan=&quot;2&quot;&gt;&amp;nbsp;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;background: #cfc; color:black; font-size: smaller;&quot;&gt;&lt;div&gt;&lt;ins style=&quot;color: red; font-weight: bold; text-decoration: none;&quot;&gt;&amp;lt;math&amp;gt;\mu = 0\textrm{.}51 &lt;/ins&gt;&amp;lt;/math&amp;gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;/table&gt;</description>
			<pubDate>Mon, 17 May 2010 11:11:18 GMT</pubDate>			<dc:creator>Ian</dc:creator>			<comments>http://wiki.sommarmatte.se/wikis/2009/bridgecoursemechanics/index.php/Talk:Solution_9.4</comments>		</item>
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			<title>Ian: New page: Image:9.4.gif  As the block is moving relative to the surface the friction force must satisfy  &lt;math&gt;F = \mu R&lt;/math&gt;  Also as the block has conmstant velocity the forces on it must be...</title>
			<link>http://wiki.sommarmatte.se/wikis/2009/bridgecoursemechanics/index.php?title=Solution_9.4&amp;diff=1129&amp;oldid=prev</link>
			<description>&lt;p&gt;New page: &lt;a href=&quot;/wikis/2009/bridgecoursemechanics/index.php/Image:9.4.gif&quot; title=&quot;Image:9.4.gif&quot;&gt;Image:9.4.gif&lt;/a&gt;  As the block is moving relative to the surface the friction force must satisfy  &amp;lt;math&amp;gt;F = \mu R&amp;lt;/math&amp;gt;  Also as the block has conmstant velocity the forces on it must be...&lt;/p&gt;
&lt;p&gt;&lt;b&gt;New page&lt;/b&gt;&lt;/p&gt;&lt;div&gt;[[Image:9.4.gif]]&lt;br /&gt;
&lt;br /&gt;
As the block is moving relative to the surface the friction force must satisfy&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;F = \mu R&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Also as the block has conmstant velocity the forces on it must be in equilibrium.&lt;br /&gt;
&lt;br /&gt;
Resolving horisontally,&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;\begin{align}&lt;br /&gt;
&amp;amp; \to :\quad 20\ \text{N}-F=0 \\ &lt;br /&gt;
&amp;amp;  \\ &lt;br /&gt;
&amp;amp; F=20\ \text{N} \\ &lt;br /&gt;
\end{align}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Resolving vertically,&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;\uparrow :\quad  R-mg=0&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;R=mg=4\times 9.81=39.24\ \text{N}&amp;lt;/math&amp;gt;&lt;/div&gt;</description>
			<pubDate>Mon, 17 May 2010 11:04:48 GMT</pubDate>			<dc:creator>Ian</dc:creator>			<comments>http://wiki.sommarmatte.se/wikis/2009/bridgecoursemechanics/index.php/Talk:Solution_9.4</comments>		</item>
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