作业君找到的参考例题:【问题】:<table><tbody><tr><td><span></span>质量为5.0kg的物体,从离地面36m高处,由静止开始匀加速下落,经3s落地,g取10m/s<sup>2</sup>,试求:<br>(1)物体下落的加速度的大小;<br>(2)下落过程中物体所受阻力的大小.</td></tr></tbody></table>【答案】:<table><tbody><tr><td>(1)由<spanmathtag="math">x=<tablestyle="display:inline-table;vertical-align:middle"cellpadding="-1"cellspacing="-1"><tbody><tr><tdstyle="border-bottom:1pxsolidblack">1</td></tr><tr><td>2</td></tr></tbody></table>a<span><span>t</span><spanstyle="vertical-align:super;font-size:90%">2</span></span></span>得,a=<spanmathtag="math"><tablestyle="display:inline-table;vertical-align:middle"cellpadding="-1"cellspacing="-1"><tbody><tr><tdstyle="border-bottom:1pxsolidblack">2x</td></tr><tr><td><span><span>t</span><spanstyle="vertical-align:super;font-size:90%">2</span></span></td></tr></tbody></table>=<tablestyle="display:inline-table;vertical-align:middle"cellpadding="-1"cellspacing="-1"><tbody><tr><tdstyle="border-bottom:1pxsolidblack">72</td></tr><tr><td>9</td></tr></tbody></table>m/<span><span>s</span><spanstyle="vertical-align:super;font-size:90%">2</span></span>=8m/<span><span>s</span><spanstyle="vertical-align:super;font-size:90%">2</span></span></span>.<br>故物体下落的加速度大小为8m/s<sup>2</sup>.<br>(2)根据牛顿第二定律得,mg-f=ma<br>则f=mg-ma=50-5×8N=10N<br>故下落过程中物体所受阻力的大小为10N.</td></tr></tbody></table><br/>
【答案】:<table><tbody><tr><td>(1)由<spanmathtag="math">x=<tablestyle="display:inline-table;vertical-align:middle"cellpadding="-1"cellspacing="-1"><tbody><tr><tdstyle="border-bottom:1pxsolidblack">1</td></tr><tr><td>2</td></tr></tbody></table>a<span><span>t</span><spanstyle="vertical-align:super;font-size:90%">2</span></span></span>得,a=<spanmathtag="math"><tablestyle="display:inline-table;vertical-align:middle"cellpadding="-1"cellspacing="-1"><tbody><tr><tdstyle="border-bottom:1pxsolidblack">2x</td></tr><tr><td><span><span>t</span><spanstyle="vertical-align:super;font-size:90%">2</span></span></td></tr></tbody></table>=<tablestyle="display:inline-table;vertical-align:middle"cellpadding="-1"cellspacing="-1"><tbody><tr><tdstyle="border-bottom:1pxsolidblack">72</td></tr><tr><td>9</td></tr></tbody></table>m/<span><span>s</span><spanstyle="vertical-align:super;font-size:90%">2</span></span>=8m/<span><span>s</span><spanstyle="vertical-align:super;font-size:90%">2</span></span></span>.<br>故物体下落的加速度大小为8m/s<sup>2</sup>.<br>(2)根据牛顿第二定律得,mg-f=ma<br>则f=mg-ma=50-5×8N=10N<br>故下落过程中物体所受阻力的大小为10N.</td></tr></tbody></table><br/>