------------------------<br/>
1.<span style="font-family: 'Times New Roman';">如图所示，一个物体沿固定斜面匀速下滑，下列说法中正确的是（</span>　　<span style="font-family: 'Times New Roman';">）</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/1403850106973151444" width="150" height="80" /></div><br/><br/>
A.<span style="font-family: 'Times New Roman';">物体</span><span style="font-family: 'Times New Roman';">所</span><span style="font-family: 'Times New Roman';">受到的滑动摩擦力</span><span style="font-family: 'Times New Roman';">沿斜面向下</span></div><br/>
B.<span style="font-family: 'Times New Roman';">斜面所</span><span style="font-family: 'Times New Roman';">受到的滑动摩擦力</span><span style="font-family: 'Times New Roman';">沿斜面向下</span><br/>
C.<span style="font-family: 'Times New Roman';">物体受到的滑动摩擦力大小与下滑速度有关</span><br/>
D.<span style="font-family: 'Times New Roman';">物体受到的滑动摩擦力大小与下滑</span><span style="font-family: 'Times New Roman';">接触面积大小</span><span style="font-family: 'Times New Roman';">有关</span><br/>
++++++++++++++++++++++++++<br/>
<b>正确答案</b>: ['B']<br/>
解析:<div class="mst-editor-mce-root-block"><span style="font-family: 'Times New Roman';">AB</span><span style="font-family: 'Times New Roman';">．斜面给物体的滑动摩擦力沿斜面向上，物体给斜面的滑动摩擦力沿斜面向下．故</span><span style="font-family: 'Times New Roman';">A</span><span style="font-family: 'Times New Roman';">错误</span><span style="font-family: 'Times New Roman';">B</span><span style="font-family: 'Times New Roman';">正确．</span><br /><span style="font-family: 'Times New Roman';"><span class="mst-text-indent" contenteditable="false">&nbsp;</span>C</span><span style="font-family: 'Times New Roman';">D</span><span style="font-family: 'Times New Roman';">．物体受到的滑动摩擦力大小与下滑速度、接触面积大小都没有关系，故</span><span style="font-family: 'Times New Roman';">CD</span><span style="font-family: 'Times New Roman';">错误．</span></div>
<div class="mst-editor-mce-root-block"><span style="font-family: 'Times New Roman';"><span class="mst-text-indent" contenteditable="false">&nbsp;</span>本题选</span><span style="font-family: 'Times New Roman';">B</span><span style="font-family: 'Times New Roman';">．</span></div><br/>
省流:[['B']]<br/>
------------------------<br/>
------------------------<br/>
2.<span style="font-family: 'Times New Roman';">如图，将一重力不计的纸夹在水平桌面上的书内，已知书对纸的压力为</span><img class="Wirisformula" style="vertical-align: -1px;" role="math" src="http://file.ewt360.com/file/1403850227232252509" data-fileid="1399302629960577482" data-type="mathType" data-wmf="http://file.ewt360.com/file/1403850106973159984" data-bin="http://file.ewt360.com/file/1403850124153013011" data-id="105431" /><span style="font-family: 'Times New Roman';">，书所受的重力为</span><img class="Wirisformula" style="vertical-align: -1px;" role="math" src="http://file.ewt360.com/file/1403850227232244170" data-fileid="1399302629960577483" data-type="mathType" data-wmf="http://file.ewt360.com/file/1403850124153036810" data-bin="http://file.ewt360.com/file/1403850167102701942" data-id="101435" /><span style="font-family: 'Times New Roman';">．若用</span><img class="Wirisformula" style="vertical-align: -1px;" role="math" src="http://file.ewt360.com/file/1403850227232227551" data-fileid="1399302629960577484" data-type="mathType" data-wmf="http://file.ewt360.com/file/1403850175692628383" data-bin="http://file.ewt360.com/file/1403850175692644720" data-id="723729" /><span style="font-family: 'Times New Roman';">的水平拉力拉纸，刚好将纸匀速拉出．则书与纸间的动摩擦因数为（　　）</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/1403850175692636856" width="254" height="108" /></div><br/><br/>
A.<img class="Wirisformula" style="vertical-align: -4px;" role="math" src="http://file.ewt360.com/file/1403850227232252511" data-fileid="1399302629960577490" data-type="mathType" data-wmf="http://file.ewt360.com/file/1403850184282554908" data-bin="http://file.ewt360.com/file/1403850184282562999" data-id="92787" /></div><br/>
B.<img class="Wirisformula" style="vertical-align: -4px" role="math" src="http://file.ewt360.com/file/1403850227232252512" data-fileid="1399302629960577491" data-type="mathType" data-wmf="http://file.ewt360.com/file/1403850184282570758" data-bin="http://file.ewt360.com/file/1403850184282554909" data-id="723726"/><br/>
C.<img class="Wirisformula" style="vertical-align: -4px" role="math" src="http://file.ewt360.com/file/1403850227232244174" data-fileid="1399302629960577492" data-type="mathType" data-wmf="http://file.ewt360.com/file/1403850184282579102" data-bin="http://file.ewt360.com/file/1403850184282570759" data-id="99003"/><br/>
D.<img class="Wirisformula" style="vertical-align: -4px" role="math" src="http://file.ewt360.com/file/1403850227232227548" data-fileid="1399302629960577493" data-type="mathType" data-wmf="http://file.ewt360.com/file/1403850192872497752" data-bin="http://file.ewt360.com/file/1403850192872513963" data-id="173038"/><br/>
++++++++++++++++++++++++++<br/>
<b>正确答案</b>: ['B']<br/>
解析:<div class="mst-editor-mce-root-block"><span style="font-family: 'Times New Roman';">将纸匀速拉出，纸处于平衡状态，由平衡条件得：</span><img class="Wirisformula" style="vertical-align: -4px;" role="math" src="http://file.ewt360.com/file/1403850227232235872" data-fileid="1399302629960577485" data-type="mathType" data-wmf="http://file.ewt360.com/file/1403850175692628384" data-bin="http://file.ewt360.com/file/1403850175692644721" data-id="723723" /><span style="font-family: 'Times New Roman';">，由于纸上下表面均受到滑动摩擦力，书对纸的上下表面的压力为</span><img class="Wirisformula" style="vertical-align: -4px;" role="math" src="http://file.ewt360.com/file/1403850227232244173" data-fileid="1399302629960577486" data-type="mathType" data-wmf="http://file.ewt360.com/file/1403850175692620388" data-bin="http://file.ewt360.com/file/1403850175692628385" data-id="723727" /><span style="font-family: 'Times New Roman';">，故纸张单面受到的滑动摩擦力为</span><img class="Wirisformula" style="vertical-align: -8px;" role="math" src="http://file.ewt360.com/file/1403850227232227550" data-fileid="1399302629960577487" data-type="mathType" data-wmf="http://file.ewt360.com/file/1403850175692636858" data-bin="http://file.ewt360.com/file/1403850175692620389" data-id="723728" /><span style="font-family: 'Times New Roman';">；</span><br /><span style="font-family: 'Times New Roman';">根据<img class="Wirisformula" style="vertical-align: -8px;" role="math" src="http://file.ewt360.com/file/1409071326916468774" data-fileid="" data-type="mathType" data-wmf="http://file.ewt360.com/file/1409071326916468772" data-bin="http://file.ewt360.com/file/1409071326916485420" data-id="730013" data-client="true" /></span><span style="font-family: 'Times New Roman';">可得，动摩擦因数：<img class="Wirisformula" style="vertical-align: -11px;" role="math" src="http://file.ewt360.com/file/1409072959004066348" data-fileid="" data-type="mathType" data-wmf="http://file.ewt360.com/file/1409072959004066346" data-bin="http://file.ewt360.com/file/1409072959004050062" data-id="730014" data-client="true" /></span><span style="font-family: 'Times New Roman';">，故</span><span style="font-family: 'Times New Roman';">B</span><span style="font-family: 'Times New Roman';">正确，</span><span style="font-family: 'Times New Roman';">ACD</span><span style="font-family: 'Times New Roman';">错误．</span><br /><span style="font-family: 'Times New Roman';">故选：</span><span style="font-family: 'Times New Roman';">B</span><span style="font-family: 'Times New Roman';">．</span></div><br/>
省流:[['B']]<br/>
------------------------<br/>
------------------------<br/>
3.<span style="font-family: 'Times New Roman';">用如图甲所示的装置可测量动摩擦因数，将一质量为</span><img class="Wirisformula" style="vertical-align: -4px;" role="math" src="http://file.ewt360.com/file/1403850227232227552" data-fileid="1399302629960577494" data-type="mathType" data-wmf="http://file.ewt360.com/file/1403850192872489732" data-bin="http://file.ewt360.com/file/1403850192872497753" data-id="85068"><span style="font-family: 'Times New Roman';">的木块和一质量为</span><img class="Wirisformula" style="vertical-align: -4px;" role="math" src="http://file.ewt360.com/file/1403850227232235874" data-fileid="1399302629960577495" data-type="mathType" data-wmf="http://file.ewt360.com/file/1403850192872506123" data-bin="http://file.ewt360.com/file/1403850192872489733" data-id="605482"><span style="font-family: 'Times New Roman';">的木板叠放于水平桌面上，弹簧测力计一端固定于铁架台支架上，另一端用细线与木块相连．匀速拉动木板在桌面上滑动（木块和木板始终没分开），稳定时，弹簧测力计的示数如图乙所示．重力加速度大小取</span><img class="Wirisformula" style="vertical-align: -4px;" role="math" src="http://file.ewt360.com/file/1403850227232227553" data-fileid="1399302629960577496" data-type="mathType" data-wmf="http://file.ewt360.com/file/1403850192872513965" data-bin="http://file.ewt360.com/file/1403850192872506124" data-id="96534"><span style="font-family: 'Times New Roman';">．</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/1403850192872489735" width="363" height="160"></div>
<span style="font-family: 'Times New Roman';">（</span><span style="font-family: 'Times New Roman';">1</span><span style="font-family: 'Times New Roman';">）图乙中弹簧测力计的示数为</span><span class="mst-question-answer-placeholder">1</span><img class="Wirisformula" style="vertical-align: -1px;" role="math" src="http://file.ewt360.com/file/1403850227232252508" data-fileid="1399302629960577497" data-type="mathType" data-wmf="http://file.ewt360.com/file/1403850201462448268" data-bin="http://file.ewt360.com/file/1403850201462440142" data-id="72"><span style="font-family: 'Times New Roman';">．</span><br><span style="font-family: 'Times New Roman';">（</span><span style="font-family: 'Times New Roman';">2</span><span style="font-family: 'Times New Roman';">）木块与木板间的动摩擦因数为</span><img class="Wirisformula" style="vertical-align: -4px;" role="math" src="http://file.ewt360.com/file/1403850227232235877" data-fileid="1399302629960577498" data-type="mathType" data-wmf="http://file.ewt360.com/file/1403850201462432278" data-bin="http://file.ewt360.com/file/1403850201462448269" data-id="103070"><span class="mst-question-answer-placeholder">2</span><span style="font-family: 'Times New Roman';">（保留</span><span style="font-family: 'Times New Roman';">2</span><span style="font-family: 'Times New Roman';">位有效数字）．</span><br><span style="font-family: 'Times New Roman';">（</span><span style="font-family: 'Times New Roman';">3</span><span style="font-family: 'Times New Roman';">）若加速拉动木板在桌面上滑动（木块和木板始终没分开），稳定时，弹簧测力计的示数</span><span class="mst-question-answer-placeholder">3</span><span style="font-family: 'Times New Roman';">（填“变大”“变小”或“不变”）．</span></div><br/><br/>
++++++++++++++++++++++++++<br/>
<b>正确答案</b>: ['<div class="mst-editor-mce-root-block"><span style="font-family: \'Times New Roman\';">2.95</span></div>', '<span style="font-family: \'Times New Roman\';">0.30</span>', '<span style="font-family: \'Times New Roman\';">不变</span>']<br/>
解析:<div class="mst-editor-mce-root-block"><span style="font-family: 'Times New Roman';">（</span><span style="font-family: 'Times New Roman';">1</span><span style="font-family: 'Times New Roman';">）弹簧测力计的精确度为</span><img class="Wirisformula" style="vertical-align: -1px;" role="math" src="http://file.ewt360.com/file/1403850227232244172" data-fileid="1399302629960577499" data-type="mathType" data-wmf="http://file.ewt360.com/file/1403850201462424236" data-bin="http://file.ewt360.com/file/1403850201462432279" data-id="100844" /><span style="font-family: 'Times New Roman';">，弹簧测力计的示数为<img class="Wirisformula" style="vertical-align: -2px;" role="math" src="http://file.ewt360.com/file/1409081729327276304" data-fileid="" data-type="mathType" data-wmf="http://file.ewt360.com/file/1409081729327276302" data-bin="http://file.ewt360.com/file/1409081729327260136" data-id="730086" data-client="true" /></span><span style="font-family: 'Times New Roman';">；</span><br /><span style="font-family: 'Times New Roman';">（</span><span style="font-family: 'Times New Roman';">2</span><span style="font-family: 'Times New Roman';">）木块对木板的压力</span><img class="Wirisformula" style="vertical-align: -4px;" role="math" src="http://file.ewt360.com/file/1403850227232235873" data-fileid="1399302629960577501" data-type="mathType" data-wmf="http://file.ewt360.com/file/1403850201462448271" data-bin="http://file.ewt360.com/file/1403850201462440145" data-id="172903" /><span style="font-family: 'Times New Roman';">，根据平衡条件，对木块有</span><img class="Wirisformula" style="vertical-align: -4px;" role="math" src="http://file.ewt360.com/file/1403850227232244171" data-fileid="1399302629960577502" data-type="mathType" data-wmf="http://file.ewt360.com/file/1403850210052366780" data-bin="http://file.ewt360.com/file/1403850210052382851" data-id="172131" /><span style="font-family: 'Times New Roman';">，根据滑动摩擦力公式</span><img class="Wirisformula" style="vertical-align: -4px;" role="math" src="http://file.ewt360.com/file/1403850227232235876" data-fileid="1399302629960577503" data-type="mathType" data-wmf="http://file.ewt360.com/file/1403850210052358396" data-bin="http://file.ewt360.com/file/1403850210052366781" data-id="171179" /><span style="font-family: 'Times New Roman';">，联立得木块与木板间的动摩擦因数</span><img class="Wirisformula" style="vertical-align: -8px;" role="math" src="http://file.ewt360.com/file/1403850227232244175" data-fileid="1399302629960577504" data-type="mathType" data-wmf="http://file.ewt360.com/file/1403850210052374975" data-bin="http://file.ewt360.com/file/1403850210052358397" data-id="723730" /><span style="font-family: 'Times New Roman';">；</span><br /><span style="font-family: 'Times New Roman';">（</span><span style="font-family: 'Times New Roman';">3</span><span style="font-family: 'Times New Roman';">）无论木板加速运动还是匀速运动，根据滑动摩擦力公式</span><img class="Wirisformula" style="vertical-align: -4px;" role="math" src="http://file.ewt360.com/file/1403850227232252513" data-fileid="1399302629960577505" data-type="mathType" data-wmf="http://file.ewt360.com/file/1403850210052382853" data-bin="http://file.ewt360.com/file/1403850210052374976" data-id="171179" /><span style="font-family: 'Times New Roman';">可知，木块受到的滑动摩擦力不变，因此弹簧测力计的示数不变．</span></div><br/>
省流:[['<div class="mst-editor-mce-root-block"><span style="font-family: \'Times New Roman\';">2.95</span></div>', '<span style="font-family: \'Times New Roman\';">0.30</span>', '<span style="font-family: \'Times New Roman\';">不变</span>']]<br/>
------------------------<br/>