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1.<span style="font-family: 宋体, SimSun;">下列关于力的说法正确的是</span><span style="font-family: 宋体, SimSun;">（　　）</span></div><br/><br/>
A.<span style="font-family: 宋体, SimSun;">将胳膊用力向外挥出未击中任何物体，说明力可以只有施力物体而没有受力物体</span></div><br/>
B.<span style="font-family: 宋体, SimSun;">只有直接接触的物体间才有力的作用</span><br/>
C.<span style="font-family: 宋体, SimSun;">力是既有大小又有方向的矢量</span><br/>
D.<span style="font-family: 宋体, SimSun;">先用手按压桌面，桌面发生形变后就会对手有一个支持力，所以物体间相互作用时，先有作用力，后有反作用力</span><br/>
++++++++++++++++++++++++++<br/>
<b>正确答案</b>: ['C']<br/>
解析:<div class="mst-editor-mce-root-block"><span style="font-family: 'Times New Roman';">A</span><span style="font-family: 宋体, SimSun;">．力不能离开物体而存在，有力的作用就一定有施力物体和受力物体，将胳膊用力向外挥出未击中任何物体，那么胳膊并没有对外施加任何作用力．人用力外挥胳膊所用的力是胳膊各部分之间存在相互作用力，施力物体和受力物体为胳膊不同的部位．故</span><span style="font-family: 'Times New Roman';">A</span><span style="font-family: 宋体, SimSun;">错误；</span><br /><span class="mst-text-indent" contenteditable="false">&nbsp;</span><span style="font-family: 'Times New Roman';">B</span><span style="font-family: 宋体, SimSun;">．电荷与电荷之间、磁极之间的相互作用力不需要接触就可以产生，故</span><span style="font-family: 'Times New Roman';">B</span><span style="font-family: 宋体, SimSun;">错误；</span><br /><span class="mst-text-indent" contenteditable="false">&nbsp;</span><span style="font-family: 'Times New Roman';">C</span><span style="font-family: 宋体, SimSun;">．力是既有大小又有方向的矢量，故</span><span style="font-family: 'Times New Roman';">C</span><span style="font-family: 宋体, SimSun;">正确；</span><br /><span class="mst-text-indent" contenteditable="false">&nbsp;</span><span style="font-family: 'Times New Roman';">D</span><span style="font-family: 宋体, SimSun;">．手与桌面相互作用时，手和桌面的形变是同时产生的，手对桌面的压力和桌面对手的支持力是同时产生的，所以物体间相互作用时，作用力和反作用力同时产生，故</span><span style="font-family: 'Times New Roman';">D</span><span style="font-family: 宋体, SimSun;">错误．</span><span style="font-family: 宋体, SimSun;">故选</span><span style="font-family: 'Times New Roman';">C</span><span style="font-family: 宋体, SimSun;">．</span></div><br/>
省流:[['C']]<br/>
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2.<span style="font-family: 宋体, SimSun;">（多选题）一个重</span><img class="Wirisformula" role="math" src="http://file.ewt360.com/file/1396353542205710991" data-fileid="1394307823513341006" data-type="mathType" data-wmf="http://file.ewt360.com/file/1396353507845947706" data-bin="http://file.ewt360.com/file/1396353507845956310" data-id="85383" /><span style="font-family: 宋体, SimSun;">的物体沿着斜面下滑，在下图中关于物体受到的重力的图示正确的是（　　）</span></div><br/><br/>
A.<div style="text-align: left;"><img src="http://file.ewt360.com/file/1396353516435906766" width="115" height="104" /></div><br/>
B.<div width="100%" style="text-align:left"><img  src=http://file.ewt360.com/file/1396353516435866177 width=125 height=98 /></div><br/>
C.<div width="100%" style="text-align:left"><img  src=http://file.ewt360.com/file/1396353516435899065 width=130 height=80 /></div><br/>
D.<div width="100%" style="text-align:left"><img  src=http://file.ewt360.com/file/1396353516435874491 width=128 height=103 /></div><br/>
++++++++++++++++++++++++++<br/>
<b>正确答案</b>: ['A', 'D']<br/>
解析:<div class="mst-editor-mce-root-block"><span style="font-family: 'Times New Roman';">B</span><span style="font-family: 宋体, SimSun;">、</span><span style="font-family: 'Times New Roman';">C</span><span style="font-family: 宋体, SimSun;">两图虽然也有标度，有向线段的长度也表示</span><img class="Wirisformula" role="math" src="http://file.ewt360.com/file/1396353542205710990" data-fileid="1394307823513341007" data-type="mathType" data-wmf="http://file.ewt360.com/file/1396353516435866175" data-bin="http://file.ewt360.com/file/1396353516435899063" data-id="85383" /><span style="font-family: 宋体, SimSun;">，但是由于其方向不是竖直向下，所以</span><span style="font-family: 'Times New Roman';">BC</span><span style="font-family: 宋体, SimSun;">错误；</span><br /><span class="mst-text-indent" contenteditable="false">&nbsp;</span><span style="font-family: 'Times New Roman';">A</span><span style="font-family: 宋体, SimSun;">、</span><span style="font-family: 'Times New Roman';">D</span><span style="font-family: 宋体, SimSun;">两图标度和线段长度均能表示力的大小为</span><img class="Wirisformula" role="math" src="http://file.ewt360.com/file/1396353542205694654" data-fileid="1394307823513341008" data-type="mathType" data-wmf="http://file.ewt360.com/file/1396353516435882028" data-bin="http://file.ewt360.com/file/1396353516435890943" data-id="85383" /><span style="font-family: 宋体, SimSun;">，方向也均是竖直向下，所以</span><span style="font-family: 'Times New Roman';">AD</span><span style="font-family: 宋体, SimSun;">正确．</span><span style="font-family: 宋体, SimSun;">故选</span><span style="font-family: 'Times New Roman';">AD</span><span style="font-family: 宋体, SimSun;">．</span></div><br/>
省流:[['A', 'D']]<br/>
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3.<span style="font-family: 宋体, SimSun;">中国结是一种中国特有的手工编织工艺品，它身上所显示的情致与智慧正是中华古老文明中的一个侧面</span><span style="font-family: 宋体, SimSun;">．</span><span style="font-family: 宋体, SimSun;">一质量为</span><img class="Wirisformula" role="math" src="http://file.ewt360.com/file/1396353542205702497" data-fileid="1394307823513341009" data-type="mathType" data-wmf="http://file.ewt360.com/file/1396353516435890944" data-bin="http://file.ewt360.com/file/1396353525025841409" data-id="517" /><span style="font-family: 宋体, SimSun;">的中国结用细绳悬挂于</span><img class="Wirisformula" role="math" src="http://file.ewt360.com/file/1396353542205694655" data-fileid="1394307823513341010" data-type="mathType" data-wmf="http://file.ewt360.com/file/1396353525025832978" data-bin="http://file.ewt360.com/file/1396353525025809111" data-id="4201" /><span style="font-family: 宋体, SimSun;">点处于静止状态，如图所示，重力加速度为</span><img class="Wirisformula" role="math" src="http://file.ewt360.com/file/1396353542205694656" data-fileid="1394307823513341011" data-type="mathType" data-wmf="http://file.ewt360.com/file/1396353525025825443" data-bin="http://file.ewt360.com/file/1396353525025841410" data-id="5340" /><span style="font-family: 宋体, SimSun;">，下列说法正确的是（　　）</span></div>
<div class="mst-editor-em-to-div" style="display: block; font-style: normal; text-align: center;"><img src="http://file.ewt360.com/file/1396353525025800449" width="57" height="140" /></div><br/><br/>
A.<span style="font-family: 宋体, SimSun;">细绳</span><img class="Wirisformula" role="math" src="http://file.ewt360.com/file/1396353542205670125" data-fileid="1394307823513341016" data-type="mathType" data-wmf="http://file.ewt360.com/file/1396353533615743774" data-bin="http://file.ewt360.com/file/1396353533615751733" data-id="5012" /><span style="font-family: 宋体, SimSun;">一定竖直</span></div><br/>
B.<span style="font-family: 宋体, SimSun;">中国结的重心一定在它的几何中心</span><br/>
C.<span style="font-family: 宋体, SimSun;">中国结的重心可能不在</span><img class="Wirisformula" style="vertical-align: -1px" role="math" src="http://file.ewt360.com/file/1396353542205678241" data-fileid="1394307823513341017" data-type="mathType" data-wmf="http://file.ewt360.com/file/1396353533615776260" data-bin="http://file.ewt360.com/file/1396353533615735465" data-id="5012"/><span style="font-family: 宋体, SimSun;">直线上</span><br/>
D.<span style="font-family: 宋体, SimSun;">中国结对细绳</span><img class="Wirisformula" style="vertical-align: -1px" role="math" src="http://file.ewt360.com/file/1396353542205670124" data-fileid="1394307823513341018" data-type="mathType" data-wmf="http://file.ewt360.com/file/1396353533615743775" data-bin="http://file.ewt360.com/file/1396353533615751734" data-id="5012"/><span style="font-family: 宋体, SimSun;">的拉力就是中国结的重力</span><br/>
++++++++++++++++++++++++++<br/>
<b>正确答案</b>: ['A']<br/>
解析:<div class="mst-editor-mce-root-block"><span style="font-family: 'Times New Roman';">AC</span><span style="font-family: 宋体, SimSun;">．由二力平衡可知，用一根线悬挂的物体静止时，线的拉力与自身重力等大反向，重力的方向竖直向下，拉力的方向也是竖直方向的，故</span><img class="Wirisformula" role="math" src="http://file.ewt360.com/file/1396353542205678242" data-fileid="1394307823513341012" data-type="mathType" data-wmf="http://file.ewt360.com/file/1396353525025809112" data-bin="http://file.ewt360.com/file/1396353525025817118" data-id="5012" /><span style="font-family: 宋体, SimSun;">一定是竖直的，中国结的重心一定在</span><img class="Wirisformula" role="math" src="http://file.ewt360.com/file/1396353542205686093" data-fileid="1394307823513341013" data-type="mathType" data-wmf="http://file.ewt360.com/file/1396353525025841411" data-bin="http://file.ewt360.com/file/1396353525025800450" data-id="5012" /><span style="font-family: 宋体, SimSun;">直线上，故</span><span style="font-family: 'Times New Roman';">A</span><span style="font-family: 宋体, SimSun;">正确，</span><span style="font-family: 'Times New Roman';">C</span><span style="font-family: 宋体, SimSun;">错误；</span><br /><span class="mst-text-indent" contenteditable="false">&nbsp;</span><span style="font-family: 'Times New Roman';">B</span><span style="font-family: 宋体, SimSun;">．由于中国结的形状不是完全对称的，质量分布不均匀，故中国结的重心不一定在它的几何中心．故</span><span style="font-family: 'Times New Roman';">B</span><span style="font-family: 宋体, SimSun;">错误；</span><br /><span class="mst-text-indent" contenteditable="false">&nbsp;</span><span style="font-family: 'Times New Roman';">D</span><span style="font-family: 宋体, SimSun;">．中国结对细绳</span><img class="Wirisformula" role="math" src="http://file.ewt360.com/file/1396353542205702496" data-fileid="1394307823513341014" data-type="mathType" data-wmf="http://file.ewt360.com/file/1396353525025809113" data-bin="http://file.ewt360.com/file/1396353533615751732" data-id="5012" /><span style="font-family: 宋体, SimSun;">的拉力大小等于中国结的重力</span><img class="Wirisformula" role="math" src="http://file.ewt360.com/file/1396353542205686094" data-fileid="1394307823513341015" data-type="mathType" data-wmf="http://file.ewt360.com/file/1396353533615776259" data-bin="http://file.ewt360.com/file/1396353533615735464" data-id="92396" /><span style="font-family: 宋体, SimSun;">，但是拉力与重力是两种不同性质的力，故</span><span style="font-family: 'Times New Roman';">D</span><span style="font-family: 宋体, SimSun;">错误．</span><span style="font-family: 宋体, SimSun;">故选</span><span style="font-family: 'Times New Roman';">A</span><span style="font-family: 宋体, SimSun;">．</span></div><br/>
省流:[['A']]<br/>
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