<p class="MsoNormal"><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">과게에</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">세계</span><span lang="ko"> </span>7<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">대</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">수학난제중에</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">하나인</span> <b>Navier-Stokes Equations</b>, <span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">이하</span><span lang="ko"> </span>NSE <span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">에</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">관하여</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">글이없기에</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">제가</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">아는</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">한도에서</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">글을</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">몇자</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">적어볼까합니다</span>.</p><p></p><p class="MsoNormal">NSE<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">는</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">점성을</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">가진</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">유체</span>, Newtonian Fluid<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">의</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">운동을</span>(<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">유체의</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">속도</span>,<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">압력</span>, <span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">온도</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">그리고</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">밀도</span>)<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">식으로</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">나타내어</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">해를</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">주는</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">방정식입니다</span>.</p><p></p><p class="MsoNormal"><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">이</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">방정식은</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">특정</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">조건하에</span> (<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">유체가</span><span lang="ko"> </span>Turbulence <span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">일경우</span>) <span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">수학적인</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">오류가</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">나게되어</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">아직까지</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">일반해는</span><span lang="ko"> 미제로 남은</span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">상태입니다</span>. <span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">그럼에도</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">불구하고</span>,NSE<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">은</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">다양한</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">분야에서</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">사용되고있는데</span>, <span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">유체를</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">예측하고</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">해석하는</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">분야</span>(Computational FluidDynamics, CFD)<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">에서는</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">필수로</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">사용된답니다</span>.</p><p></p><p class="MsoNormal">NSE<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">는</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">세가지의</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">기초</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">보존법칙</span>, </p><p></p><p class="MsoListParagraphCxSpFirst" style="text-indent:-18pt;">1)<span style="font-size:7pt;line-height:normal;font-family:'Times New Roman';"> </span>Conservation of Mass (Continuity Equation) – <span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">질량</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">보존의</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">법칙</span></p><p></p><p class="MsoListParagraphCxSpMiddle" style="text-indent:-18pt;">2)<span style="font-size:7pt;line-height:normal;font-family:'Times New Roman';"> </span>Conservation of Momentum – <span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">운동량</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">보존의</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">법칙</span></p><p></p><p class="MsoListParagraphCxSpLast" style="text-indent:-18pt;">3)<span style="font-size:7pt;line-height:normal;font-family:'Times New Roman';"> </span>Conservation of Energy – <span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">에너지</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">보전의</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">법칙</span></p><p></p><p class="MsoNormal"><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">로</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">구성되어</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">있습니다</span>.<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">이제</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">하나하나</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">알아보도록</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">하겠습니다</span></p><p></p><p class="MsoNormal"><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;"><span style="font-family:'굴림';">------------------------------------------------------------------</span></span></p><p class="MsoNormal"><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;"><b>1) 질량 보존의 법칙</b></span></p><p class="MsoNormal"><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">우선</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">첫</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">공식인</span><span lang="ko"> </span>Conservation of Mass <span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">부터</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">알아보도록</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">하겠습니다</span>.<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">질량</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">보존의</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">법칙은</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">두가지의</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">형태로</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">유도가</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">가능한데</span>, Eulerian<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">과</span> Lagrangian<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">의</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">유도방법이있습니다</span>.(<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">저는</span> Lagrangian<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">이</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">더</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">익숙하기에</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">이</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">방법으로</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">설명드릴까합니다</span>.<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">혹시</span><span lang="ko"> </span>Eulerian derivation<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">이</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">관심있으시다면</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">링크를</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">참조하시길</span>… <a target="_blank" href="https://www.grc.nasa.gov/www/k-12/airplane/eulereqs.html" target="_blank">https://www.grc.nasa.gov/www/k-12/airplane/eulereqs.html</a>)</p><p></p><p class="MsoNormal"><span style="font-size:9pt;line-height:1.5;">Lagrangian</span><span lang="ko" style="font-size:9pt;line-height:1.5;font-family:'Malgun Gothic', sans-serif;">은</span><span lang="ko" style="font-size:9pt;line-height:1.5;"> </span><span lang="ko" style="font-size:9pt;line-height:1.5;font-family:'Malgun Gothic', sans-serif;">유체의</span><span lang="ko" style="font-size:9pt;line-height:1.5;"> </span><span lang="ko" style="font-size:9pt;line-height:1.5;font-family:'Malgun Gothic', sans-serif;">흐름에</span><span lang="ko" style="font-size:9pt;line-height:1.5;"> </span><span lang="ko" style="font-size:9pt;line-height:1.5;font-family:'Malgun Gothic', sans-serif;">따른</span><span lang="ko" style="font-size:9pt;line-height:1.5;"> </span><span lang="ko" style="font-size:9pt;line-height:1.5;font-family:'Malgun Gothic', sans-serif;">질량을</span><span lang="ko" style="font-size:9pt;line-height:1.5;"> </span><span lang="ko" style="font-size:9pt;line-height:1.5;font-family:'Malgun Gothic', sans-serif;">관점으로</span><span lang="ko" style="font-size:9pt;line-height:1.5;"> </span><span lang="ko" style="font-size:9pt;line-height:1.5;font-family:'Malgun Gothic', sans-serif;">보고있습니다</span><span style="font-size:9pt;line-height:1.5;">.</span></p><p class="MsoNormal"></p><p></p><p class="MsoNormal"><span style="font-size:11pt;line-height:107%;font-family:Calibri, sans-serif;"></span></p><div style="text-align:left;"><img src="http://thimg.todayhumor.co.kr/upfile/201510/1443762603WgkY7zp18MfXCi78KL.png" width="610" height="50" alt="1.PNG" style="border:none;"></div><div style="text-align:left;"><br></div><span lang="ko" style="font-size:11pt;line-height:107%;font-family:'Malgun Gothic', sans-serif;">쉽게</span><span lang="ko" style="font-size:11pt;line-height:107%;font-family:Calibri, sans-serif;"> </span><span lang="ko" style="font-size:11pt;line-height:107%;font-family:'Malgun Gothic', sans-serif;">말해</span><span style="font-size:11pt;line-height:107%;font-family:Calibri, sans-serif;">, </span><span lang="ko" style="font-size:11pt;line-height:107%;font-family:'Malgun Gothic', sans-serif;">어떠한</span><span lang="ko" style="font-size:11pt;line-height:107%;font-family:Calibri, sans-serif;"> </span><span lang="ko" style="font-size:11pt;line-height:107%;font-family:'Malgun Gothic', sans-serif;">계의</span><span lang="ko" style="font-size:11pt;line-height:107%;font-family:Calibri, sans-serif;"> </span><span lang="ko" style="font-size:11pt;line-height:107%;font-family:'Malgun Gothic', sans-serif;">한</span><span lang="ko" style="font-size:11pt;line-height:107%;font-family:Calibri, sans-serif;"> </span><span lang="ko" style="font-size:11pt;line-height:107%;font-family:'Malgun Gothic', sans-serif;">측면으로</span><span lang="ko" style="font-size:11pt;line-height:107%;font-family:Calibri, sans-serif;"> </span><span lang="ko" style="font-size:11pt;line-height:107%;font-family:'Malgun Gothic', sans-serif;">나가는</span><span lang="ko" style="font-size:11pt;line-height:107%;font-family:Calibri, sans-serif;"> </span><span lang="ko" style="font-size:11pt;line-height:107%;font-family:'Malgun Gothic', sans-serif;">유체</span><span lang="ko" style="font-size:11pt;line-height:107%;font-family:Calibri, sans-serif;"> </span><span lang="ko" style="font-size:11pt;line-height:107%;font-family:'Malgun Gothic', sans-serif;">질량의</span><span lang="ko" style="font-size:11pt;line-height:107%;font-family:Calibri, sans-serif;"> </span><span lang="ko" style="font-size:11pt;line-height:107%;font-family:'Malgun Gothic', sans-serif;">비율은</span><span lang="ko" style="font-size:11pt;line-height:107%;font-family:Calibri, sans-serif;"> </span><span lang="ko" style="font-size:11pt;line-height:107%;font-family:'Malgun Gothic', sans-serif;">그</span><span lang="ko" style="font-size:11pt;line-height:107%;font-family:Calibri, sans-serif;"> </span><span lang="ko" style="font-size:11pt;line-height:107%;font-family:'Malgun Gothic', sans-serif;">계의</span><span lang="ko" style="font-size:11pt;line-height:107%;font-family:Calibri, sans-serif;"> </span><span lang="ko" style="font-size:11pt;line-height:107%;font-family:'Malgun Gothic', sans-serif;">속에</span><span lang="ko" style="font-size:11pt;line-height:107%;font-family:Calibri, sans-serif;"> </span><span lang="ko" style="font-size:11pt;line-height:107%;font-family:'Malgun Gothic', sans-serif;">축적되는</span><span lang="ko" style="font-size:11pt;line-height:107%;font-family:Calibri, sans-serif;"> </span><span lang="ko" style="font-size:11pt;line-height:107%;font-family:'Malgun Gothic', sans-serif;">비율과</span><span lang="ko" style="font-size:11pt;line-height:107%;font-family:Calibri, sans-serif;"> </span><span lang="ko" style="font-size:11pt;line-height:107%;font-family:'Malgun Gothic', sans-serif;">같다입니다</span><span style="font-size:11pt;line-height:107%;font-family:Calibri, sans-serif;">.</span><p></p><p class="MsoNormal"><span style="font-size:11pt;line-height:107%;font-family:Calibri, sans-serif;"></span></p><div style="text-align:left;"><img src="http://thimg.todayhumor.co.kr/upfile/201510/1443762641MBbhAjD7Y2dOuODNMTi.jpg" width="300" height="248" alt="2.jpg" style="border:none;"></div><div style="text-align:left;"><br></div><p></p><p class="MsoNormal"><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">다음을</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">식으로</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">표현하면</span></p><p></p><p class="MsoNormal"><img src="http://thimg.todayhumor.co.kr/upfile/201510/1443762718Vl73wpOeVhinY9hIo3sxCwfW3OHY.png" width="166" height="47" alt="3.PNG" style="font-family:Calibri, sans-serif;font-size:11pt;line-height:107%;border:none;"></p><p class="MsoNormal"><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">위</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">그림에서</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">본다면</span>,X<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">축에서의</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">유체</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">질량의</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">비율은</span></p><p></p><p class="MsoNormal"><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;"><br></span></p><div style="text-align:left;"></div><p class="MsoNormal"><span style="font-size:11pt;line-height:107%;font-family:Calibri, sans-serif;"></span></p><div style="text-align:left;"><img src="http://thimg.todayhumor.co.kr/upfile/201510/1443762718K1ns79f3N.png" width="261" height="87" alt="4.PNG" style="border:none;"></div><p></p><p class="MsoNormal"><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">그리고</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">질량</span>, m <span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">은</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">밀도와</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">부피를</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">곱한값이므로,</span></p><div style="text-align:left;"></div><p class="MsoNormal"><span style="font-size:11pt;line-height:107%;font-family:Calibri, sans-serif;"></span></p><div style="text-align:left;"><img src="http://thimg.todayhumor.co.kr/upfile/201510/1443762717ECkd4cQiCd.png" width="151" height="60" alt="5.PNG" style="border:none;"></div><p></p><p class="MsoNormal"><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">따라서</span>, x<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">축에</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">대하여</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">유체</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">질량비율은</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">다음과같이</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">정리됩니다</span></p><p></p><div style="text-align:left;"></div><p class="MsoNormal"><span style="font-size:11pt;line-height:107%;font-family:Calibri, sans-serif;"></span></p><div style="text-align:left;"><img src="http://thimg.todayhumor.co.kr/upfile/201510/1443762717vNZtlOzJqdSoWMmDvOd9.png" width="250" height="58" alt="6.PNG" style="border:none;"></div><p></p><p class="MsoNormal"><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">같은방식으로</span><span lang="ko"> </span>y<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">와</span><span lang="ko"> </span>x<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">축으로</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">유체</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">질량비율을</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">나타내면</span><span lang="ko"> </span></p><p></p><div style="text-align:left;"></div><p class="MsoNormal"><span style="font-size:11pt;line-height:107%;font-family:Calibri, sans-serif;"></span></p><div style="text-align:left;"><img src="http://thimg.todayhumor.co.kr/upfile/201510/1443762716WEabirojOVNTAPaD.png" width="247" height="119" alt="7.PNG" style="border:none;"></div><p></p><p class="MsoNormal">x,y,z<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">의</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">질량비율식을</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">하나로</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">묶어</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">표현하면</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">다음과</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">같이됩니다</span>.</p><p></p><p class="MsoNormal"></p><div style="text-align:left;"><img src="http://thimg.todayhumor.co.kr/upfile/201510/1443762887OTBF4sCLwt8VDiGWb7.png" width="419" height="60" alt="8.PNG" style="border:none;"></div><p></p><p class="MsoNormal"><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">양변의</span><span lang="ko"> </span>dxdydz<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">를</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">없애주고</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">방정식으로</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">만들면</span><span lang="ko"> </span>Lagrangian continuityequation<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">이</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">유도되었습니다</span>.</p><p></p><div style="text-align:left;"></div><p class="MsoNormal"></p><div style="text-align:left;"><img src="http://thimg.todayhumor.co.kr/upfile/201510/1443762886Fy9B8PQ4AieMWB2stB.png" width="287" height="71" alt="9.PNG" style="border:none;"></div><div style="text-align:left;">어때요 참 쉽죠옹? </div><div style="text-align:left;"><br></div><div style="text-align:left;">------------------------------------------------------------------</div><div style="text-align:left;"><br></div><div style="text-align:left;"><b>2) <span lang="ko" style="font-size:9pt;line-height:1.5;text-indent:-24px;font-family:'Malgun Gothic', sans-serif;">운동량</span><span lang="ko" style="font-size:9pt;line-height:1.5;text-indent:-24px;"> </span><span lang="ko" style="font-size:9pt;line-height:1.5;text-indent:-24px;font-family:'Malgun Gothic', sans-serif;">보존의</span><span lang="ko" style="font-size:9pt;line-height:1.5;text-indent:-24px;"> </span><span lang="ko" style="font-size:9pt;line-height:1.5;text-indent:-24px;font-family:'Malgun Gothic', sans-serif;">법칙</span></b></div><p></p><p class="MsoNormal"><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">이제</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">운동량</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">보존의</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">법칙을</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">살펴볼차례입니다</span>.</p><p></p><div><p class="MsoNormal"><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">대게</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">공대에서</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">유도되는</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">공식들</span>, <span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">아니</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">아마</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">이과에서</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">유도되는</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">거의</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">대부분의</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">공식들은</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">이</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">식에서</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">첫</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">발을</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">띠웁니다</span>. <span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">다들</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">알고계시는</span>, </p><p></p></div><p class="MsoNormal"></p><div style="text-align:left;"><img src="http://thimg.todayhumor.co.kr/upfile/201510/1443762886VSNTFI2setKnJXdXPqsKF.png" width="108" height="57" alt="10.PNG" style="border:none;"></div><p></p><p class="MsoNormal">Newton’s Second Law<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">이죠</span>. <span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">물체의</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">작용되는</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">힘의</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">합은</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">그</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">물체의</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">무게와</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">가속도를</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">곱한값이다</span>.</p><p></p><div><p class="MsoNormal"><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">가속도</span>, a<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">는</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">속도를</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">시간으로</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">적분한</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">값이기에</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">위의</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">식은</span></p><p></p></div><p class="MsoNormal"></p><div style="text-align:left;"><img src="http://thimg.todayhumor.co.kr/upfile/201510/1443762886rRL6lcTrrbAmYtQP4t.png" width="139" height="85" alt="11.PNG" style="border:none;"></div><p></p><p class="MsoNormal"><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">으로</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">표현됩니다</span>.</p><p></p><div><p class="MsoNormal"><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">식에서의</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">힘은</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">두가지의</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">큰</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">형태로</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">나뉘어집니다</span>. </p><p></p></div><p class="MsoNormal"></p><div style="text-align:left;"><img src="http://thimg.todayhumor.co.kr/upfile/201510/1443762885sm3nWnUQaCe4D56Tmt9Q2Ky.png" width="800" height="126" alt="12.PNG" class="chimg_photo" style="border:none;"></div><p></p><p class="MsoNormal"><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">따라서</span>, <span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">위</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">식은</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">다음과</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">같이</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">정리됩니다</span>.</p><div style="text-align:left;"></div><p class="MsoNormal"></p><div style="text-align:left;"><img src="http://thimg.todayhumor.co.kr/upfile/201510/1443762885fIYH9JJoqbjuWfTDOjJT.png" width="277" height="65" alt="13.PNG" style="border:none;"></div><div style="text-align:left;"><br></div><p></p><p class="MsoNormal">Body force<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">는</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">중력만</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">작용하는</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">경우가</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">대부분이므로</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">나머지</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">힘들은</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">제외하겠습니다</span>.</p><p></p><div><p class="MsoNormal"><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">따라서</span><span lang="ko"> </span></p><div style="text-align:left;"><img src="http://thimg.todayhumor.co.kr/upfile/201510/1443763050kdVNMq5BpnA.png" width="167" height="28" alt="14.PNG" style="border:none;"></div> <span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">로</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">간단하게</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">표현됩니다</span>.(fx<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">는</span>x<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">축에서의</span> body force per unit mass)<p></p><p></p><p class="MsoNormal"><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">그러면</span> Surface force<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">가</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">관건인데요</span>,</p><p></p><p class="MsoNormal"><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">이</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">부분은 </span>3 dimensional stress tensor<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">를</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">파고</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">들어야합니다</span>. <span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">차근차근</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">집어봅시다</span>.</p><p></p><p class="MsoNormal"></p><div style="text-align:left;"><img src="http://thimg.todayhumor.co.kr/upfile/201510/14437630971E1HmjjgwESAq.png" width="599" height="535" alt="15.PNG" style="border:none;"></div><br><p></p></div><p class="MsoNormal">위는 Shear stress <span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">와</span><span lang="ko"> </span>Normalstress<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">를 아주 작은 유체입자에</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">나타낸</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">그림입니다</span>. <span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">전자는</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">유체입자의</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">표면</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">장력</span>(τ)<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">이고</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">후자는</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">표면</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">압력</span>(P)<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">을</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">뜻합니다</span>. <span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">표면</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">장력은</span> 6<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">개</span>, <span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">압력은</span> 3<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">개로</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">총</span> 9<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">개의</span><span lang="ko"> </span>stress<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">로</span><span lang="ko"> </span>stress tensor<font face="Malgun Gothic, sans-serif">를</font><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">구성</span><span lang="ko">합</span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">니다</span>.</p><p></p><p class="MsoNormal"></p><p class="MsoNormal"><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">표면장력은 </span></p><div style="text-align:left;"><img src="http://thimg.todayhumor.co.kr/upfile/201510/1443763173enA6cCIQpmAry8EigdlF.png" width="26" height="26" alt="16.PNG" style="border:none;"></div><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">로</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">나타내어</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">지는데</span>, <span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">밑항의</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">뜻은 </span>τstress<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">가</span><span lang="ko"> </span>i<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">축</span>(x) <span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">의</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">표면에서</span><span lang="ko"> </span>j <span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">축</span> (y) <span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">방향으로</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">가해진다는</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">뜻입니다</span>. <span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">즉</span>, <span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">위</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">그림에서</span>x<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">방향의</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">표면</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">장력은</span><span lang="ko"> </span>6<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">군데</span><span lang="ko"> </span><div style="text-align:left;"><img src="http://thimg.todayhumor.co.kr/upfile/201510/1443763198t4MLAoVFP6M51d5EPb7FziBcYg.png" width="446" height="39" alt="17.PNG" style="border:none;"></div><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">로 작용받고있고,</span> <p></p><p></p><div style="text-align:left;"></div><div style="text-align:left;"></div><p class="MsoNormal"><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">표면압력은</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">정해진</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">축의</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">방향으로</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">가해지게</span><span lang="ko"> <font face="Malgun Gothic, sans-serif">되므로</font></span> x<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">방향에서의</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">표면압력은</span></p><p class="MsoNormal"><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;"></span></p><div style="text-align:left;"><img src="http://thimg.todayhumor.co.kr/upfile/201510/1443763371NGZjzK2HjZa9lCoaobp.png" width="120" height="33" alt="18.PNG" style="border:none;"></div>로<span lang="ko"> <font face="Malgun Gothic, sans-serif">이루어져있습니다</font></span>.<p></p><p></p><p class="MsoNormal"><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">종합하면</span> x<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">축에서의</span> Surface force<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">는</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">다음과</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">같이</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">됩니다</span>.</p><p></p><p class="MsoNormal"></p><div style="text-align:left;"><img src="http://thimg.todayhumor.co.kr/upfile/201510/1443763417C4JKlYKG.png" width="658" height="100" alt="19.PNG" style="border:none;"></div><p></p><p class="MsoNormal">이 두가지 힘, Surface force<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">와</span> Body force<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">를</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">더해</span>x<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">축에 작용되는</span><span lang="ko"> </span>Net force(알짜힘)<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">를</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">구하면</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">다음식이</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">됩니다</span>.</p><p></p><div style="text-align:left;"></div><p class="MsoNormal"></p><div style="text-align:left;"><img src="http://thimg.todayhumor.co.kr/upfile/201510/1443763418NWZxJ97asZFxN6A8tMgNgrc7nXsp.png" width="492" height="61" alt="20.PNG" style="border:none;"></div><p></p><p class="MsoNormal">Newton<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">의</span> 2<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">법칙을</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">적용하여</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">다음과같이</span><span lang="ko"> 좌항을 변환시켜</span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">줍니다</span></p><p></p><div style="text-align:left;"></div><p class="MsoNormal"></p><div style="text-align:left;"><img src="http://thimg.todayhumor.co.kr/upfile/201510/1443763418ma9LQryxUI8xj9fH9EDVzaOz2PPSqC.png" width="505" height="74" alt="21.PNG" style="border:none;"></div><p></p><p class="MsoNormal"><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">앞서와같이</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">질량</span>, m<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">은</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">밀도와</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">부피의</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">곱이므로</span></p><p></p><div style="text-align:left;"></div><p class="MsoNormal"></p><div style="text-align:left;"><img src="http://thimg.todayhumor.co.kr/upfile/201510/1443763418gvhxGKezkjta1K.png" width="556" height="73" alt="22.PNG" style="border:none;"></div><p></p><p class="MsoNormal"><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">또</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">양변의</span><span lang="ko"> </span>dxdydz<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">를</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">없애주면</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">다음과</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">같습니다</span>.</p><p></p><div style="text-align:left;"></div><p class="MsoNormal"></p><div style="text-align:left;"><img src="http://thimg.todayhumor.co.kr/upfile/201510/1443763419KsmyEoAy.png" width="386" height="72" alt="23.PNG" style="border:none;"><br></div><p></p><p class="MsoNormal"><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">여기서의</span><span lang="ko"> Du/Dt</span> <span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">는</span><span lang="ko"> </span>Substantialderivative<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">라는</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">것인데</span>, <span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">이</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">주제로만해도</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">아마</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">몇시간은</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">잡아먹을것같아</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">다음차에</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">설명드리겠습니다</span>.<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">간단하게</span><span lang="ko"> </span>mathematical tool <span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">이라고</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">보시면</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">되겠습니다</span>.</p><p></p><div style="text-align:left;"></div><p class="MsoNormal"></p><div style="text-align:left;"><img src="http://thimg.todayhumor.co.kr/upfile/201510/1443763419Sg6bDq3jraOMa7OYP4l.png" width="175" height="64" alt="24.PNG" style="border:none;"></div><p></p><p class="MsoNormal"><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">그러므로</span></p><p></p><div style="text-align:left;"></div><p class="MsoNormal"></p><div style="text-align:left;"><img src="http://thimg.todayhumor.co.kr/upfile/201510/1443763420luzdzj6cXnTHKb.png" width="178" height="59" alt="25.PNG" style="border:none;"></div><p></p><p class="MsoNormal"><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">또한</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">이</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">식은</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">다르게 표현되어 다음과 같이 표기됩니다.</span></p><p></p><div style="text-align:left;"></div><p class="MsoNormal"></p><div style="text-align:left;"><img src="http://thimg.todayhumor.co.kr/upfile/201510/1443763420EbUb7iYja1Z8j9zAesPALyCHPFq39f3s.png" width="276" height="62" alt="26.PNG" style="border:none;"></div><p></p><p class="MsoNormal"><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">최종적으로</span> x<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">축의</span> Net force<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">는</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">다음과같이</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">유도가</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">됩니다</span>.</p><p></p><div style="text-align:left;"></div><p class="MsoNormal"></p><div style="text-align:left;"><img src="http://thimg.todayhumor.co.kr/upfile/201510/1443763421HBwkpIwXNQpAFnbVs62dPzG55.png" width="575" height="88" alt="27.PNG" style="border:none;"></div><p></p><p class="MsoNormal"><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">같은</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">방법으로</span> y<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">와</span> z<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">축의</span><span lang="ko"> </span>Net force<span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">를</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">구해주면</span><span lang="ko"> </span><span lang="ko" style="font-family:'Malgun Gothic', sans-serif;">다음과같습니다</span>.</p><p></p><div style="text-align:left;"></div><p class="MsoNormal"></p><div style="text-align:left;"><img src="http://thimg.todayhumor.co.kr/upfile/201510/14437634213KFpH4ydrpzLMXuq5M1HoNUNK2NpE1.png" width="602" height="186" alt="28.PNG" style="border:none;"></div><div style="text-align:left;">---------------------------------------------------------------</div><p></p><font face="Malgun Gothic, sans-serif"><br>쓰다보니 시간이 훅훅갔네요, 당장 내일이 다른과목시험인데 ㅎㅎ... 에너지보존법칙은 덧글로 이어가겠습니다 ㅠㅠ... 그럼 오늘은 20000</font><br><p class="MsoNormal"><br></p><div style="text-align:left;"></div>
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Claude-Louis Navier 그리고 George Gabriel Stokes |
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