20春学期《理论力学》在线平时作业2

adminhan

&nbsp; <p class="MsoNormal"><span lang="EN-US">4.2 </span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">空间平行力系的平衡方程为三个：</span><span lang="EN-US">_{<v:shapetype id="_x0000_t75" stroked="f" filled="f" path="m@4@5l@4@11@9@11@9@5xe" o:preferrelative="t" o:spt="75" coordsize="21600,21600"> <img width="212" height="27" alt="" src="http://file.open.com.cn/ItemDB/43586/eb779b0a-0865-4983-b92b-1ea2205d9cd2/2009101319626934.gif" /><v:stroke joinstyle="miter"></v:stroke><v:formulas><v:f eqn="if lineDrawn pixelLineWidth 0"></v:f><v:f eqn="sum @0 1 0"></v:f><v:f eqn="sum 0 0 @1"></v:f><v:f eqn="prod @2 1 2"></v:f><v:f eqn="prod @3 21600 pixelWidth"></v:f><v:f eqn="prod @3 21600 pixelHeight"></v:f><v:f eqn="sum @0 0 1"></v:f><v:f eqn="prod @6 1 2"></v:f><v:f eqn="prod @7 21600 pixelWidth"></v:f><v:f eqn="sum @8 21600 0"></v:f><v:f eqn="prod @7 21600 pixelHeight"></v:f><v:f eqn="sum @10 21600 0"></v:f></v:formulas><v:path o:connecttype="rect" gradientshapeok="t" o:extrusionok="f"></v:path><o:lock aspectratio="t" v:ext="edit"></o:lock></v:shapetype>}</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">。（</span><span lang="EN-US"><span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp; </span></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">）</span></p>
A:对
B:错

<p class="MsoNormal"><span style="mso-bidi-font-size: 10.5pt" lang="EN-US">14.2 </span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-size: 10.5pt">物体系统由质量分别为</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US">mA</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-size: 10.5pt">和</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US">mB</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-size: 10.5pt">的两物体</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US">A</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-size: 10.5pt">和</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US">B</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-size: 10.5pt">组成，放置在光滑水平面上。若此系统上作用一水平力</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US">F</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-size: 10.5pt">，用动静法可说明</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US">A</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-size: 10.5pt">和</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US">B</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-size: 10.5pt">两物体之间相互作用力大小为</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US">F</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-size: 10.5pt">。（）</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><o:p></o:p></span></p><p class="MsoNormal"><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><span style="mso-spacerun: yes">&nbsp;&nbsp;</span></span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span></span></p>
A:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span style="mso-spacerun: yes"> </span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-size: 10.5pt">正确</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp;</span></span>
B:&nbsp;&nbsp;&nbsp;&nbsp;<span style="mso-spacerun: yes"> </span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-size: 10.5pt">错误</span>

<p style="LINE-HEIGHT: 150%; MARGIN: 0cm 0cm 0pt" class="MsoNormal"><span style="LINE-HEIGHT: 150%; FONT-SIZE: 10.5pt" lang="EN-US"><font face="Times New Roman">2.3</font></span><span style="LINE-HEIGHT: 150%; FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: Verdana">平面汇交力系的必要和充分条件是各力在两个坐标轴上投影的代数和</span><span style="LINE-HEIGHT: 150%; FONT-SIZE: 10.5pt" lang="EN-US"><font face="Times New Roman">(&nbsp; &nbsp;&nbsp; )</font></span><span style="LINE-HEIGHT: 150%; FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">。</span><span style="LINE-HEIGHT: 150%; FONT-SIZE: 10.5pt" lang="EN-US"><o:p></o:p></span></p><p style="LINE-HEIGHT: 150%; TEXT-INDENT: 10.5pt; MARGIN: 0cm 0cm 0pt; mso-char-indent-count: 1.0" class="MsoNormal"><span style="LINE-HEIGHT: 150%; FONT-SIZE: 10.5pt" lang="EN-US"><font face="Times New Roman">&nbsp;&nbsp;</font></span></p><p style="LINE-HEIGHT: 150%; TEXT-INDENT: 10.5pt; MARGIN: 0cm 0cm 0pt; mso-char-indent-count: 1.0" class="MsoNormal"><span style="LINE-HEIGHT: 150%; FONT-SIZE: 10.5pt" lang="EN-US"><font face="Times New Roman">&nbsp;&nbsp;</font></span></p>
A:<span style="LINE-HEIGHT: 150%; FONT-SIZE: 10.5pt" lang="EN-US"><font face="Times New Roman">&nbsp;&nbsp;&nbsp;&nbsp;</font></span><span style="LINE-HEIGHT: 150%; FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: Verdana">一个大于</span><span style="LINE-HEIGHT: 150%; FONT-SIZE: 10.5pt" lang="EN-US"><font face="Times New Roman">0</font></span><span style="LINE-HEIGHT: 150%; FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: Verdana">，一个小于</span><span style="LINE-HEIGHT: 150%; FONT-SIZE: 10.5pt" lang="EN-US"><font face="Times New Roman">0&nbsp;</font></span>
B:&nbsp;<span style="LINE-HEIGHT: 150%; FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: Verdana">．都等于</span><span style="LINE-HEIGHT: 150%; FONT-SIZE: 10.5pt" lang="EN-US"><font face="Times New Roman">0 <o:p></o:p></font></span>
C:&nbsp;<span style="LINE-HEIGHT: 150%; FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: Verdana">都小于</span><span style="LINE-HEIGHT: 150%; FONT-SIZE: 10.5pt" lang="EN-US"><font face="Times New Roman">0&nbsp;</font></span>
D:&nbsp;<span style="LINE-HEIGHT: 150%; FONT-SIZE: 10.5pt" lang="EN-US"><font face="Times New Roman">&nbsp;&nbsp;&nbsp;</font></span><span style="LINE-HEIGHT: 150%; FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: Verdana">都大于</span><span style="LINE-HEIGHT: 150%; FONT-SIZE: 10.5pt" lang="EN-US"><font face="Times New Roman">0 </font></span>

<p style="MARGIN: 0cm 0cm 0pt" class="MsoNormal"><font size="3"><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><font face="Times New Roman">3.2 </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-size: 10.5pt">平面力系向点</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><font face="Times New Roman">1</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-size: 10.5pt">简化时，主矢</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><font face="Times New Roman">F&rsquo;</font></span></font><font face="Times New Roman"><span style="FONT-SIZE: 5pt" lang="EN-US">R</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><font size="3">=0</font></span></font><font size="3"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-size: 10.5pt">，主矩</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><font face="Times New Roman">M</font></span></font><strong style="mso-bidi-font-weight: normal"><span style="FONT-FAMILY: 宋体; FONT-SIZE: 5pt" lang="EN-US">1</span></strong><font size="3"><strong style="mso-bidi-font-weight: normal"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt">&ne;</span></strong><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt" lang="EN-US">0</span><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt">，如将该力系向另一点<span lang="EN-US">2</span>简化，则（<span lang="EN-US"><span style="mso-spacerun: yes">&nbsp;&nbsp; </span></span>）。<span lang="EN-US"><o:p></o:p></span></span></font></p><p style="MARGIN: 0cm 0cm 0pt" class="MsoNormal"><font size="3"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt" lang="EN-US"><span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp;</span></span></font><font size="3"><strong style="mso-bidi-font-weight: normal"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt"><span lang="EN-US"><span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span></span></span></strong></font></p><p style="TEXT-INDENT: 31.5pt; MARGIN: 0cm 0cm 0pt; mso-char-indent-count: 3.0" class="MsoNormal"><font face="Times New Roman"><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><font size="3"><span style="mso-spacerun: yes">&nbsp;</span></font></span></font></p>
A:<font size="3"><font face="宋体">&nbsp;<span style="mso-spacerun: yes"> </span>F</font><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><font face="Times New Roman">&rsquo;</font></span></font><font face="Times New Roman"><span style="FONT-SIZE: 5pt" lang="EN-US">R</span><font size="3"><strong style="mso-bidi-font-weight: normal"><span style="mso-bidi-font-size: 10.5pt" lang="EN-US">&ne;0</span></strong><span style="mso-bidi-font-size: 10.5pt" lang="EN-US">,M</span></font><span style="FONT-SIZE: 5pt" lang="EN-US">2</span></font><font size="3"><strong style="mso-bidi-font-weight: normal"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt">&ne;<span lang="EN-US">0<span style="mso-spacerun: yes">&nbsp;</span></span></span></strong></font>
B:<font size="3"><strong><font face="宋体">&nbsp;&nbsp;</font></strong><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt" lang="EN-US"><span style="mso-spacerun: yes"> </span>F&rsquo;</span></font><span style="FONT-SIZE: 5pt" lang="EN-US"><font face="Times New Roman"> R</font></span><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt" lang="EN-US"><font size="3"> =0,M</font></span><font face="Times New Roman"><span style="FONT-SIZE: 5pt" lang="EN-US">2</span><strong style="mso-bidi-font-weight: normal"><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><font size="3">&ne;M</font></span></strong><strong style="mso-bidi-font-weight: normal"><span style="FONT-SIZE: 5pt" lang="EN-US">1</span></strong><span style="FONT-SIZE: 5pt" lang="EN-US"><o:p></o:p></span></font>
C:<font face="Times New Roman"><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><font size="3"><span style="mso-spacerun: yes">&nbsp;</span>F&rsquo;</font></span><span style="FONT-SIZE: 5pt" lang="EN-US"> R</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><font size="3"> =0,M</font></span><span style="FONT-SIZE: 5pt" lang="EN-US">2</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><font size="3">=M </font></span><strong style="mso-bidi-font-weight: normal"><span style="FONT-SIZE: 5pt" lang="EN-US">1</span></strong><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><font size="3"><span style="mso-spacerun: yes">&nbsp;&nbsp;</span></font></span></font>
D:<font face="Times New Roman"><font size="3">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; F&rsquo;<strong style="mso-bidi-font-weight: normal"> </strong></font><span style="FONT-SIZE: 5pt" lang="EN-US">R</span><strong style="mso-bidi-font-weight: normal"><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><font size="3">&ne;0,M</font></span></strong><span style="FONT-SIZE: 5pt" lang="EN-US">2</span><strong style="mso-bidi-font-weight: normal"><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><font size="3">=M</font></span></strong><strong style="mso-bidi-font-weight: normal"><span style="FONT-SIZE: 5pt" lang="EN-US">1<o:p></o:p></span></strong></font>

&nbsp; <p class="MsoNormal"><span style="mso-bidi-font-size: 10.5pt" lang="EN-US">1.1 </span><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">在任何情况下</span><u><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span></u><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">的物体称为刚体。</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><o:p></o:p></span></p>
A:<span style="FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">都不移动；</span>
B:<strong style="mso-bidi-font-weight: normal"><span style="FONT-FAMILY: 'Times New Roman'; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA"><span style="mso-spacerun: yes">&nbsp;</span></span></strong><span style="FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">都不运动；</span>
C:<span style="FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">都不动；</span>
D:<span style="FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">都不变形</span><strong style="mso-bidi-font-weight: normal"><span style="FONT-FAMILY: 'Times New Roman'; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA" lang="EN-US">.</span></strong>

<p style="MARGIN: 0cm 0cm 0pt" class="MsoNormal"><font size="3"><span lang="EN-US"><font face="Times New Roman">3.1 </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">作用在一个刚体上的两个力</span><strong style="mso-bidi-font-weight: normal"><span lang="EN-US"><font face="Times New Roman">F</font></span></strong></font><strong style="mso-bidi-font-weight: normal"><span style="FONT-SIZE: 5pt" lang="EN-US"><font face="Times New Roman">A</font></span></strong><font size="3"><strong style="mso-bidi-font-weight: normal"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-size: 10.5pt">、</span></strong><strong style="mso-bidi-font-weight: normal"><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><font face="Times New Roman">F</font></span></strong></font><strong style="mso-bidi-font-weight: normal"><span style="FONT-SIZE: 5pt" lang="EN-US"><font face="Times New Roman">B</font></span></strong><font size="3"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-size: 10.5pt">满足</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><font face="Times New Roman">F</font></span></font><font face="Times New Roman"><span style="FONT-SIZE: 5pt" lang="EN-US">A</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><font size="3">=-F</font></span><span style="FONT-SIZE: 5pt" lang="EN-US">B</span></font><font size="3"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-size: 10.5pt">的条件，则该二力可能是（</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><span style="mso-spacerun: yes"><font face="Times New Roman">&nbsp;&nbsp; </font></span></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-size: 10.5pt">）。</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><o:p></o:p></span></font></p><p style="MARGIN: 0cm 0cm 0pt" class="MsoNormal"><font size="3"><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><font face="Times New Roman"><span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span></font></span></font></p><p style="MARGIN: 0cm 0cm 0pt" class="MsoNormal"><font size="3"><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><font face="Times New Roman"><span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span></font></span></font></p>
A:<font size="3"><font face="Times New Roman">&nbsp;&nbsp;&nbsp;<span style="mso-spacerun: yes">&nbsp;&nbsp; </span></font><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-size: 10.5pt">作用力和反作用力或一对平衡的力</span></font>
B:<font size="3"><span style="mso-spacerun: yes"><font face="Times New Roman">&nbsp;&nbsp; </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-size: 10.5pt">一对平衡的力或一个力偶</span></font>
C:<span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-size: 10.5pt"><font size="4">一对平衡的力或一个力和一个力偶</font></span>
D:<font size="3"><span style="mso-spacerun: yes"><font face="Times New Roman">&nbsp;&nbsp; </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-size: 10.5pt">作用力和反作用力或一个力偶</span></font>

&nbsp; <p class="MsoNormal"><span lang="EN-US">1.3 </span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">柔体约束反力的指向不能确定。（</span><span lang="EN-US"><span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp; </span></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">）</span></p>
A:对
B:错

&nbsp; <p class="MsoNormal"><span lang="EN-US">2.1 </span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">如果</span><em style="mso-bidi-font-style: normal"><span lang="EN-US">F</span></em>_{<span lang="EN-US">1</span>}<span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">与</span><em style="mso-bidi-font-style: normal"><span lang="EN-US">F</span></em>_{<span lang="EN-US">2</span>}<span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">在</span><em style="mso-bidi-font-style: normal"><span lang="EN-US">x</span></em><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">轴上投影相等，这两个力一定相等。（</span><span lang="EN-US"><span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp; </span></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">）</span></p>
A:对
B:错

&nbsp; <p class="MsoNormal"><span lang="EN-US">3.5 </span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">一个结构包含的未知量个数正好等于此结构所能建立的独立平衡方程的个数，则此结构为静定结构。（</span><span lang="EN-US"><span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp; </span></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">）</span></p>
A:对
B:错

<p style="MARGIN: 0cm 0cm 0pt" class="MsoNormal"><font size="3"><span lang="EN-US"><font face="Times New Roman">4.2</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">、</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-size: 10.5pt">某一力偶系，若其力偶矩矢构成的多边形是封闭的，则该力偶系向一点简化时</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><font face="Times New Roman">(<span style="mso-spacerun: yes">&nbsp; </span>)</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-size: 10.5pt">。</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><o:p></o:p></span></font></p><p style="MARGIN: 0cm 0cm 0pt" class="MsoNormal"><font size="3"><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><font face="Times New Roman"><span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp;&nbsp; </span></font></span></font></p><p style="MARGIN: 0cm 0cm 0pt" class="MsoNormal"><font size="3"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-size: 10.5pt"></span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><o:p></o:p></span></font></p><p style="TEXT-INDENT: 26.25pt; MARGIN: 0cm 0cm 0pt; mso-char-indent-count: 2.5" class="MsoNormal"><font size="3"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-size: 10.5pt"></span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><o:p></o:p></span></font></p><p style="MARGIN: 0cm 0cm 0pt" class="MsoNormal"><font size="3"><span lang="EN-US"><font face="Times New Roman"><span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp;</span></font></span></font></p>
A:<span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-size: 10.5pt"><font size="3">主矢不一定等于零，主矩一定等于零。</font></span>
B:<p><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-size: 10.5pt"><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><font face="Times New Roman"><font size="3"><span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp;&nbsp; </span></font></font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-size: 10.5pt"><font size="3">主矢一定等于零，主矩不一定等于零。</font></span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><o:p></o:p></span></span></p>
C:<font size="3"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-size: 10.5pt">主矢一定等于零，主矩也一定等于零。</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><o:p></o:p></span></font>
D:<font size="3">&nbsp; <span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-size: 10.5pt">主矢不一定等于零，主矩也不一定等于零。</span></font>

&nbsp; <p class="MsoNormal"><span lang="EN-US">10.2 </span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">牛顿三定律适用于</span><u><span lang="EN-US"><span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span></u><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">。</span></p>
A:<span style="FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">直角坐标系</span>
B:<strong style="mso-bidi-font-weight: normal"><span style="FONT-FAMILY: 'Times New Roman'; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA"><span style="mso-spacerun: yes">&nbsp;</span></span></strong><span style="FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">自然坐标系；</span>
C:<span style="FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">惯性参考系；</span>
D:<span style="FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">平面参考系</span><strong style="mso-bidi-font-weight: normal"><span style="FONT-FAMILY: 'Times New Roman'; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA" lang="EN-US">.</span></strong>

&nbsp; <p class="MsoNormal"><span lang="EN-US">2.4 </span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">物体在平面汇交力系作用下平衡的必要与充分条件是</span><u><span lang="EN-US"><span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span></u><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">。</span></p>
A:<span style="FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">各力在</span><em style="mso-bidi-font-style: normal"><span style="FONT-FAMILY: 'Times New Roman'; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA" lang="EN-US">x</span></em><span style="FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">轴的投影等于零；</span>
B:<span style="FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">各力在</span><em style="mso-bidi-font-style: normal"><span style="FONT-FAMILY: 'Times New Roman'; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA" lang="EN-US">y</span></em><span style="FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">轴的投影等于零；</span>
C:<span style="FONT-FAMILY: 'Times New Roman'; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA"><span style="mso-spacerun: yes">&nbsp;</span></span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">合力等于零</span>

<p style="MARGIN: 0cm 0cm 0pt" class="MsoNormal"><font size="3"><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><font face="Times New Roman">3.3 </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-size: 10.5pt">已知一平面力系向力系所在平面内</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><font face="Times New Roman">A</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-size: 10.5pt">、</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><font face="Times New Roman">B</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-size: 10.5pt">两点简化的主矩</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><font face="Times New Roman">M</font></span></font><font face="Times New Roman"><strong style="mso-bidi-font-weight: normal"><span style="FONT-SIZE: 5pt" lang="EN-US">A</span></strong><strong style="mso-bidi-font-weight: normal"><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><font size="3">&ne;0</font></span></strong></font><font size="3"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-size: 10.5pt">，</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><font face="Times New Roman">M</font></span></font><font face="Times New Roman"><strong style="mso-bidi-font-weight: normal"><span style="FONT-SIZE: 5pt" lang="EN-US">B</span></strong><strong style="mso-bidi-font-weight: normal"><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><font size="3">&ne;0</font></span></strong></font><font size="3"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-size: 10.5pt">，则该力系简化的结果有以下几种可能（</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><span style="mso-spacerun: yes"><font face="Times New Roman">&nbsp; </font></span></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-size: 10.5pt">）。</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><o:p></o:p></span></font></p><p style="MARGIN: 0cm 0cm 0pt" class="MsoNormal"><font size="3"><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><font face="Times New Roman"><span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp;&nbsp;</span></font></span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><font face="Times New Roman"><span style="mso-spacerun: yes">&nbsp;&nbsp;</span></font></span></font></p>
A:<font size="3"><font face="Times New Roman">&nbsp; </font><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-size: 10.5pt">合力</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><font face="Times New Roman"><span style="mso-spacerun: yes">&nbsp;&nbsp;</span></font></span></font>
B:<font size="3"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-size: 10.5pt">合力或合力偶</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><font face="Times New Roman"><span style="mso-spacerun: yes">&nbsp;&nbsp;</span></font></span></font>
C:<font face="Times New Roman"><font size="3">&nbsp;&nbsp;<span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><span style="mso-spacerun: yes">&nbsp; </span></span></font></font><font size="3"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-size: 10.5pt">合力偶</span><span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><font face="Times New Roman"><span style="mso-spacerun: yes">&nbsp;</span></font></span></font>
D:<span style="mso-bidi-font-size: 10.5pt" lang="EN-US"><font face="Times New Roman"><font size="3"><span style="mso-spacerun: yes">&nbsp;</span><span style="mso-spacerun: yes"> </span></font></font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-size: 10.5pt"><font size="3">不能简化</font></span>

<p style="LINE-HEIGHT: 37.5pt" class="MsoNormal"><span style="COLOR: black; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt" lang="EN-US">9.3<o:p></o:p></span></p><p style="LINE-HEIGHT: 37.5pt" class="MsoNormal"><span style="COLOR: black; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt" lang="EN-US">8</span><span style="FONT-FAMILY: 宋体; COLOR: black; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: ??; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt">．某瞬时平面图形上（图</span><span style="COLOR: black; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt" lang="EN-US">8</span><span style="FONT-FAMILY: 宋体; COLOR: black; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: ??; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt">）任两点</span><span style="COLOR: black; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt" lang="EN-US">A</span><span style="FONT-FAMILY: 宋体; COLOR: black; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: ??; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt">、</span><span style="COLOR: black; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt" lang="EN-US">B</span><span style="FONT-FAMILY: 宋体; COLOR: black; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: ??; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt">的速度为</span><span style="COLOR: black; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt" lang="EN-US">vA</span><span style="FONT-FAMILY: 宋体; COLOR: black; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: ??; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt">和</span><span style="COLOR: black; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt" lang="EN-US">vB</span><span style="FONT-FAMILY: 宋体; COLOR: black; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: ??; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt">，则</span><span style="COLOR: black; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt" lang="EN-US">AB</span><span style="FONT-FAMILY: 宋体; COLOR: black; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: ??; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt">连线中点</span><span style="COLOR: black; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt" lang="EN-US">C</span><span style="FONT-FAMILY: 宋体; COLOR: black; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: ??; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt">的速度为（</span><span style="COLOR: black; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt"> </span><span style="FONT-FAMILY: 宋体; COLOR: black; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: ??; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt">）。</span><span style="COLOR: black; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt" lang="EN-US"> <o:p></o:p></span></p><p style="LINE-HEIGHT: 37.5pt; mso-pagination: widow-orphan" class="MsoNormal"><span style="COLOR: black; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt" lang="EN-US"><img alt="" width="118" height="169" v:shapes="_x0000_i1075" src="http://file.open.com.cn/ItemDB/43586/d4672ca9-2221-4836-bebd-be8cb7fe8e53/200952114838165.jpg" /><o:p></o:p></span></p>
A:<span style="COLOR: black; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt" lang="EN-US">&nbsp;vC</span><span style="FONT-FAMILY: 宋体; COLOR: black; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: ??; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt">＝</span><span style="COLOR: black; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt" lang="EN-US">vA</span><span style="FONT-FAMILY: 宋体; COLOR: black; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: ??; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt">＋</span><span style="COLOR: black; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt" lang="EN-US">vB</span>
B:&nbsp;vC<span style="FONT-FAMILY: 宋体; COLOR: black; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: ??; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt">＝</span><span style="COLOR: black; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt" lang="EN-US">vA</span><span style="FONT-FAMILY: 宋体; COLOR: black; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: ??; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt">－</span><span style="COLOR: black; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt" lang="EN-US">vB</span>
C:<span style="COLOR: black; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt" lang="EN-US">&nbsp;vC</span><span style="FONT-FAMILY: 宋体; COLOR: black; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: ??; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt">＝（</span><span style="COLOR: black; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt" lang="EN-US">vA</span><span style="FONT-FAMILY: 宋体; COLOR: black; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: ??; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt">＋</span><span style="COLOR: black; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt" lang="EN-US">vB</span><span style="FONT-FAMILY: 宋体; COLOR: black; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: ??; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt">）</span><span style="COLOR: black; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt" lang="EN-US">∕2</span>
D:<span style="COLOR: black; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt" lang="EN-US">&nbsp;vC</span><span style="FONT-FAMILY: 宋体; COLOR: black; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: ??; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt">＝（</span><span style="COLOR: black; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt" lang="EN-US">vA</span><span style="FONT-FAMILY: 宋体; COLOR: black; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: ??; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt">－</span><span style="COLOR: black; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt" lang="EN-US">vB</span><span style="FONT-FAMILY: 宋体; COLOR: black; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: ??; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt">）</span><span style="COLOR: black; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt" lang="EN-US">∕2</span>

<p style="LINE-HEIGHT: 37.5pt; mso-pagination: widow-orphan" class="MsoNormal"><span style="COLOR: black; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt" lang="EN-US">9. 4</span><span style="FONT-FAMILY: 宋体; COLOR: black; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: ??; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt">图</span><span style="COLOR: black; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt" lang="EN-US">9</span><span style="FONT-FAMILY: 宋体; COLOR: black; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: ??; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt">所示圆盘在水平面上无滑动地滚动，角速度</span><span style="COLOR: black; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt" lang="EN-US"><img alt="" width="29" height="15" v:shapes="_x0000_i1076" src="http://file.open.com.cn/ItemDB/43586/0ca1f144-971d-4b86-bdf5-1d4660f2f2c4/20095211494634.jpg" /></span><span style="FONT-FAMILY: 宋体; COLOR: black; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: ??; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt">常数，轮边</span><span style="COLOR: black; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt" lang="EN-US">B</span><span style="FONT-FAMILY: 宋体; COLOR: black; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: ??; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt">点的加速度为（</span><span style="COLOR: black; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt"> </span><span style="FONT-FAMILY: 宋体; COLOR: black; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: ??; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt">）。</span><span style="COLOR: black; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt" lang="EN-US"> <o:p></o:p></span></p><p style="LINE-HEIGHT: 37.5pt; mso-pagination: widow-orphan" class="MsoNormal"><span style="COLOR: black; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt" lang="EN-US"><img alt="" width="189" height="151" v:shapes="_x0000_i1080" src="http://file.open.com.cn/ItemDB/43586/0ca1f144-971d-4b86-bdf5-1d4660f2f2c4/200952114921462.jpg" /><o:p></o:p></span></p>
A:<span style="COLOR: black; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt" lang="EN-US">&nbsp;0 </span>
B:<img alt="" width="31" height="21" v:shapes="_x0000_i1077" src="http://file.open.com.cn/ItemDB/43586/0ca1f144-971d-4b86-bdf5-1d4660f2f2c4/200952114938290.jpg" />
C:<img alt="" width="40" height="21" v:shapes="_x0000_i1078" src="http://file.open.com.cn/ItemDB/43586/0ca1f144-971d-4b86-bdf5-1d4660f2f2c4/200952114955915.jpg" />
D:<img alt="" width="40" height="21" v:shapes="_x0000_i1079" src="http://file.open.com.cn/ItemDB/43586/0ca1f144-971d-4b86-bdf5-1d4660f2f2c4/2009521141014509.jpg" />

&nbsp; <p class="MsoNormal"><span lang="EN-US">7.3</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">在同一瞬时，刚体内所有各点的总加速度与其法向加速度的夹角相同。（</span><span lang="EN-US"><span style="mso-spacerun: yes">&nbsp;&nbsp; </span><span style="mso-spacerun: yes">&nbsp;</span></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">）</span></p>
A:对
B:错

<p class="MsoNormal"><span style="FONT-SIZE: 10.5pt" lang="EN-US">6.1</span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">点作直线运动，已知某瞬时加速度</span><span style="FONT-SIZE: 10.5pt" lang="EN-US">a=-2</span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">米每平方秒，</span><span style="FONT-SIZE: 10.5pt" lang="EN-US">t=1s</span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">时速度</span><span style="FONT-SIZE: 10.5pt" lang="EN-US">v=2m/s</span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">，则</span><span style="FONT-SIZE: 10.5pt" lang="EN-US">t=2s</span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">时，该点的速度大小（）</span><span style="FONT-SIZE: 10.5pt" lang="EN-US"><o:p></o:p></span></p><p class="MsoNormal"><span style="FONT-SIZE: 10.5pt" lang="EN-US"><span style="mso-spacerun: yes">&nbsp;</span></span></p>
A:<font size="3">&nbsp;0<span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp;</span></font>
B:<span style="FONT-SIZE: 10.5pt" lang="EN-US">-2m/s<span style="mso-spacerun: yes">&nbsp;</span></span>
C:<span style="FONT-SIZE: 10.5pt" lang="EN-US"><span style="mso-spacerun: yes">&nbsp;&nbsp; </span>4m/s<span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp;</span></span>
D:<font size="3"><span style="mso-spacerun: yes">&nbsp;</span></font><span style="FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">无法确定</span>

&nbsp; <p class="MsoNormal"><span lang="EN-US">3.2 </span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">当平面一般力系简化结果是主矢不等于零、主矩不等于零时，合成结果为</span><u><span lang="EN-US"><span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span></u><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">。</span></p>
A:<span style="FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">合力，作用线通过简化中心</span>
B:<span style="FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">力偶；</span>
C:<span style="FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">合力，作用线不通过简化中心；</span>
D:<span style="FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">平衡</span><strong style="mso-bidi-font-weight: normal"><span style="FONT-FAMILY: 'Times New Roman'; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA" lang="EN-US">.</span></strong>

<p style="LINE-HEIGHT: 150%" class="MsoNormal"><span lang="EN-US">10.2 </span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">质量分别为</span><span lang="EN-US">m₁=m</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">、</span><span lang="EN-US">m₂=2m</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">的两个小球</span><span lang="EN-US">M₁</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">、</span><span lang="EN-US">M₂</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">用长为</span><em style="mso-bidi-font-style: normal"><span lang="EN-US">l</span></em><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">而重力不计的刚杆相连。现将</span><span lang="EN-US">M₁</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">置于光滑水平面上，且</span><span lang="EN-US">M₁M₂</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">与水平面呈</span><span lang="EN-US">60</span>^{<span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">。</span>}<span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">角，则无初速释放，</span><span lang="EN-US">M₂</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">球落地时，</span><span lang="EN-US">M₁</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">球移动的水平距离为（）。</span></p><p style="LINE-HEIGHT: 150%; TEXT-INDENT: 21.75pt" class="MsoNormal"><span lang="EN-US"></span></p>
A:<span lang="EN-US"><em style="mso-bidi-font-style: normal">l</em>/6<span style="mso-spacerun: yes">&nbsp;&nbsp;</span></span>
B:<em style="mso-bidi-font-style: normal">l</em>/4<span style="mso-spacerun: yes">&nbsp;&nbsp;</span>
C:<span style="mso-spacerun: yes">&nbsp;</span><em style="mso-bidi-font-style: normal">l</em>/3<span style="mso-spacerun: yes">&nbsp;&nbsp;</span>
D:<p style="LINE-HEIGHT: 150%; TEXT-INDENT: 21.75pt" class="MsoNormal"><span lang="EN-US"><span style="mso-spacerun: yes">&nbsp;</span><span style="mso-spacerun: yes">&nbsp;</span><span style="mso-spacerun: yes">&nbsp;</span><span style="mso-spacerun: yes">&nbsp; </span>0</span></p>

<p style="LINE-HEIGHT: 37.5pt; mso-pagination: widow-orphan" class="MsoNormal"><span style="COLOR: black; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt" lang="EN-US">9.2</span><span style="FONT-FAMILY: 宋体; COLOR: black; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: ??; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt">图</span><span style="COLOR: black; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt" lang="EN-US">7</span><span style="FONT-FAMILY: 宋体; COLOR: black; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: ??; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt">所示机构中作平面运动的构件在图示位置的速度瞬心是（</span><span style="COLOR: black; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt"> </span><span style="FONT-FAMILY: 宋体; COLOR: black; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: ??; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt">）。</span><span style="COLOR: black; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt" lang="EN-US"> <o:p></o:p></span></p><p style="LINE-HEIGHT: 37.5pt; mso-pagination: widow-orphan" class="MsoNormal"><span style="COLOR: black; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt">&nbsp;<span lang="EN-US"><img alt="" width="184" height="114" v:shapes="_x0000_i1074" src="http://file.open.com.cn/ItemDB/43586/6ed95a2d-2e46-40a8-b7e3-6f3aca80fae2/20095211481425.jpg" /><o:p></o:p></span></span></p>
A:<span style="COLOR: black; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt" lang="EN-US">A</span><span style="FONT-FAMILY: 宋体; COLOR: black; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: ??; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt">点</span><span style="COLOR: black; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt"> </span>
B:<span style="COLOR: black; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt"><span lang="EN-US">&nbsp;O</span></span><span style="FONT-FAMILY: 宋体; COLOR: black; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: ??; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt">点</span>
C:<span style="COLOR: black; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt"><span lang="EN-US">B</span></span><span style="FONT-FAMILY: 宋体; COLOR: black; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: ??; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt">点</span>
D:<span style="COLOR: black; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt"><span lang="EN-US">&nbsp;</span></span><span style="FONT-FAMILY: 宋体; COLOR: black; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: ??; mso-bidi-font-size: 10.5pt; mso-font-kerning: 0pt">无穷远点</span>