解析分类汇编高三物理学生版单元功和能

E/r/n/r/n单元/r/n/r/n功/r/n和/r/n/r/nE/r/n单元/r/n/r/n功和/r/n /r/n/r/n /r/n功和/r/n功/r/n /r/n/r/n /r/n动/r/n能/r/n/r/n动/r/n能/r/n定/r/n /r/n/r/n /r/n机械能/r/n守/r/n恒/r/n定/r/n /r/n/r/n /r/n实验：/r/n探/r/n究/r/n动/r/n能/r/n定/r/n /r/n/r/n /r/n实验：/r/n验/r/n证/r/n机/r/n械/r/n能/r/n守/r/n恒/r/n定/r/n /r/n/r/n /r/n功和能综/r/n /r/n/r/n答/r/n案/r/n与/r/n解/r/n /r/n/r/n /r/n功和/r/n功/r/n /r/n/r/n /r/n动/r/n能/r/n/r/n动/r/n能/r/n定/r/n /r/n/r/n /r/n机械能/r/n守/r/n恒/r/n定/r/n /r/n/r/n /r/n实验：/r/n探/r/n究/r/n动/r/n能/r/n定/r/n /r/n/r/n /r/n实验：/r/n验/r/n证/r/n机/r/n械/r/n能/r/n守/r/n恒/r/n定/r/n /r/n/r/n /r/n功和能综/r/n /r/n /r/n功/r/n和/r/n功/r/n/r/n物块/r/na/r/n通过/r/n平行于传送带的轻绳跨过光滑轻滑轮与物块/r/nb/r/n相连，/r/nb/r/n的质量为/r/nm/r/n，开始时/r/na/r/n、/r/nb/r/n及传送带/r/n均/r/n，且/r/na/r/n不受传送带摩擦力作用，/r/n现让传送带逆时针匀速转动，/r/n则在/r/nb/r/n上升/r/nh/r/n高度（未与滑轮相碰）/r/n过/r/n（ /r/na/r/nθ/r/na/r/n/r/na/r/nθ/r/n摩擦力对/r/na/r/n/r/n做的功大于/r/na/r/n/r/n机械能/r/n的增/r/n /r/na/r/n/r/na/r/n、/r/nb/r/n/r/na/r/n、/r/nb/r/n/r/n/r/na/r/n开始运动，当其速度达到勘后，便以此速度做匀速运/r/n关于上述过程，以下判断正确的是（重力加速度为/r/ng/r/n（/r/n /r/nA/r/n．μ/r/na/r/n/r/n之间一定满足关系/r/nC/r/n．煤块从开始运动到相对于传送/r/n带/r/n经历的时间/r/n（/r/n2014/r/n·吉/r/n林市普高二模）3./r/n，/r/n长为/r/nL/r/n的粗糙/r/n长木板水平放置，/r/n在木板的/r/nA/r/n端放/r/nm/r/nA/r/n端，使木板以左端为轴转动，当木板转到与水/r/ng/r/n。下列判断正确的是（/r/n/r/n）/r/nB．/r/nmgLsinα/r/n（/r/n2014/r/n·/r/n襄阳四中/r/n模/r/n拟/r/n）4./r/n有/r/n两/r/n个形状/r/n和/r/n大/r/n小均相/r/n同/r/n的/r/n圆台形/r/n容/r/n器/r/n，/r/n球/r/n．/r/n使/r/n两/r/n球/r/n脱/r/n离/r/n底/r/n部/r/n，/r/n最/r/n终/r/n木/r/n球/r/n浮/r/n于/r/n水/r/n面/r/n．/r/n木/r/n球/r/n上/r/n升/r/n过/r/n体/r/n积/r/n不/r/n变/r/n，该/r/n过/r/n重力对两球做的功分别为Ｗ/r/n甲/r/n和Ｗ/r/n乙/r/n，/r/n则（/r/n/r/n）/r/n·/r/n（/r/n2014/r/n/r/n武昌/r/n5/r/n月模拟）/r/n5./r/n/r/n下表/r/n列出了某种型号轿车的部分数据/r/n,/r/n表格右侧图为轿车/r/n·/r/n增大，/r/nR/r/n/r/n是/r/n挡。试问若轿车在额定功率下/r/n,/r/n要以最大动力上坡/r/n,/r/n变速杆应推至哪一档？/r/n最高速度运行时/r/n,/r/n轿车的牵引力约为多大（）/r/nA/r/n“/r/n5/r/n”/r/n /r/nB/r/n“/r/n5/r/n”/r/nC/r/n“/r/n1/r/n”/r/n /r/nD/r/n“/r/n1/r/n”/r/n0/r/n5/r/nt/r/n/r/n0/r/n11./r/n（/r/n2014/r/n·山西/r/n大学附中/r/n5/r/n月月考）/r/n6. /r/n在离出发线/r/n5m/r/n、/r/n10m/r/n、/r/n20m/r/n、/r/n30m/r/n、……/r/n70m/r/n/r/n的/r/n地方分别划上/r/n8/r/n/r/n条计时线，每条计时线附/r/n0/r/n5/r/nt/r/n/r/n0/r/n11./r/n各段距离△/r/n①/r/n②/r/n①/r/n/r/n（/r/nm/r/n//r/ns/r/n；②/r/n（/r/nm/r/n//r/ns/r/nv/r/n/r/nx/r/n/r/nv/r/n～/r/nx/r/n/r/n（/r/n0/r/n～/r/n5m/r/n/r/n段的平均速度已画出/r/n本次实验中，设学生和自行车在各段△/r/nx/r/n内所受阻力与其速度大小成正比（比例系/r/n数为/r/nK/r/n，/r/n则在各段平均阻力做功的表达式/r/nW/r/n= /r/n（用题/r/n设字母表示/r/n；若整个/r/n过/r/n该同学骑车的功率/r/nP/r/n保持不变，则/r/nP/r/n= /r/nE2/r/n/r/n动能动/r/n能/r/n定/r/n（/r/n2014/r/n·湖南十三校第二次联考）1.一质量为/r/nm/r/nEko/r/n从地面竖/r/n0/r/n</r/nk<1/r/n，/r/n /r/n上升/r/n过/r/n阻力大小恒定且/r/n上升高/r/n度/r/n时，重力势能和动能相/r/n上升高/r/n 时，动能与重力势能之差/r/n（/r/n2014/r/n·黑龙江大庆铁人中学模拟）2./r/n一辆卡车质量/r/nM=4000kg/r/n，拖车质量/r/nm=2000kg/r/n。在平直/r/n公/r/n以/r/nv=10m/s/r/n/r/n的速度匀速/r/n行驶，阻力为车重的/r/n0.05/r/n倍，途中拖车突然脱掉，从/r/nB/r/nA/r/n（/r/n2014/r/n·江/r/n苏徐州一中/r/n模拟）/r/n3./r/n/r/n，/r/n劲度系数为/r/nk/r/n＝/r/n200N/m/r/n的/r/n轻/r/n质/r/n弹/r/n簧/r/n，/r/n上/r/n端/r/n固/r/n定/r/n，/r/n下/r/n端/r/n连/r/n一/r/n质/r/n量/r/nm/r/n=3kg/r/n/r/n的/r/n物/r/n块/r/nA/r/n，/r/nA/r/n/r/n放/r/n在/r/n平/r/n台/r/nB/r/n/r/n上，平/r/nB/r/nA/r/nB/r/n一起下降直到分离，求：/r/nB/r/nA/r/n⑴/r/nAB/r/n/r/nB/r/na/r/n=5m/s/r/n2/r/n向下匀加速运动，/r/nA/r/n、/r/nB/r/n/r/n⑶若/r/nB/r/n以/r/na/r/n=5m/s/r/n2/r/n向下匀加速运动，从开始运动到/r/nA/r/n、/r/nB/r/n分离的过程/r/n/r/n簧弹性势能的/r/n变/r/nB/r/nA/r/n做的功．/r/n（/r/n2014/r/n·江/r/n西师大附中、/r/n鹰潭一中/r/n5/r/n月联考）/r/n4. /r/n/r/nx/r/n,/r/nx/r/n与木板倾角/r/n/r/n的关系/r/n。/r/ng/r/n取/r/n10m/s/r/n2/r/n。求（结果如果是根号，可以保留/r/n：/r/nv/r/n0/r/nμ/r/n/r/n当/r/nα/r/n /r/n /r/n0/r/n（/r/n2014/r/n·/r/n武昌/r/n5/r/n/r/n月模拟）/r/n5. /r/n，一质量为/r/nm/r/n的/r/n物块/r/nA/r/n/r/n与竖直轻弹簧的上端/r/n连接，/r/n弹簧的下端固定在地面上，/r/n一质量也为/r/nm/r/n的物块/r/nB/r/n放在/r/nA/r/n的上面，/r/nA/r/n、/r/nB/r/n处/r/n于/r/n状态。若/r/nA/r/n、/r/nB/r/n/r/n粘连在一起，用一竖直向上的拉力缓慢上提/r/nB/r/n，当/r/n

/r/n时，/r/nA/r/n/r/n物块上升的高度为/r/nL/r/n，此/r/n过/r/n，该拉力做的功为/r/n2/r/nA/r/n、/r/nB/r/nF/r/nB/r/nA/r/n物块上升的高度也/r/nL/r/n时，/r/nA/r/n、/r/nB/r/ng/r/n，不计空气阻力，求：/r/nF/r/n/r/n（/r/n2/r/n）/r/nA/r/n/r/nB/r/n/r/n /r/n机/r/n械/r/n能/r/n守/r/n恒/r/n定/r/nC/r/n（/r/n2014/r/n·吉林九校联合体第二次摸底）1./r/n/r/nm/r/n/r/nC/r/n（可看做质点）/r/nA/r/n/r/n /r/n /r/n至/r/n最/r/n置/r/nC/r/n/r/n点（/r/n图/r/n丙/r/n途/r/n中/r/n经/r/n过/r/n位/r/n置/r/nB/r/n/r/n时/r/n弹/r/n簧/r/n正/r/n好/r/n处/r/n于/r/n状态（/r/n图/r/n乙/r/n。/r/n已/r/n知/r/nAB/r/n/r/n的/r/n高/r/n度/r/n差/r/n为/r/nh/r/n1/r/n，/r/nBC/r/n/r/n的/r/n高/r/n度/r/n差/r/n为/r/nh/r/n2/r/n，/r/n重/r/n力/r/ng/r/n，不计空气阻力。则（/r/n/r/n）/r/nA/r/n．小球从/r/nA/r/n/r/n上升到/r/nB/r/n/r/n位置的/r/n过/r/n，动能增/r/nB/r/n．小球从/r/nA/r/n上升到/r/nC/r/n位置的/r/n过/r/n，机械能一直增大/r/nC/r/nmg/r/n/r/nh/r/n2/r/n/r/n/r/n/r/nh/r/n1/r/n/r/n/r/nD/r/nh/r/n2/r/n/r/n/r/n/r/nh/r/n1/r/n

/r/nA/r/n /r/n /r/nB/r/n /r/nB/r/n端系着小球。/r/n小球从/r/nA/r/n点/r/n，/r/n运动到/r/nB/r/n点的/r/n过/r/n，/r/n不计空气阻力/r/nA/r/n则/r/n /r/n/r/n（/r/n2014/r/n·/r/n二中模拟/r/n /r/n如图/r/n/r/n9/r/n，/r/n在/r/n倾/r/n斜角为/r/n/r/n的/r/n光/r/n滑/r/n斜/r/n面/r/n上/r/n放/r/n一/r/n轻/r/n质/r/n弹/r/n簧/r/n，/r/n其/r/n端固定/r/n/r/n时上端位置在/r/nB/r/n点/r/n在/r/nA/r/n点放上一质量/r/nm/r/n/r/n2.0/r/nkg/r/n的小物体/r/n小物体/r/n，从开始的一段时间内/r/n的/r/nv/r/n/r/nt/r/n图像如图/r/n10/r/n/r/n所示，小物体/r/n在/r/n0.4/r/ns/r/n时运动到/r/nB/r/n/r/n点/r/n,/r/n在/r/n0.9s/r/n/r/n到达/r/nC/r/n点，/r/nBC/r/n的距离为/r/n1.2m/r/n（/r/ng/r/n/r/n/r/n10/r/nm/r/n//r/ns/r/n2/r/n/r/n，由图知 /r/n /r/nA/r/n、/r/n斜/r/n面/r/n倾/r/n斜/r/n角/r/n/r/n/r/n/r/n6/r/nB/r/n、物体从/r/nB/r/n/r/n运动到/r/nC/r/n/r/n的/r/n过/r/n机械能守/r/nC/r/nC/r/n/r/nD/r/n、物快从/r/nC/r/n/r/n点回到/r/nA/r/n/r/n点/r/n过/r/n，加速度先增后减，再保持不/r/n（/r/n2014/r/n·/r/n武昌/r/n5/r/n月/r/n模拟）/r/n4./r/n/r/n，/r/n在光滑的水平地面上有一个表面光滑的立方/r/ngL/r/n(1/r/n/r/nQ/r/n。一长为/r/nL/r/nO/r/n点/r/n,O/r/n点固定/r/nQ/r/n/r/n的质量相等/r/n,/r/n小球靠在立方体左侧，杆竖直，整个装/r/n置/r/n处/r/n于/r/n状/r/n态/r/n。/r/n受/r/n到/r/n轻/r/n微/r/n扰/r/n动/r/n后/r/n/r/nP/r/n/r/n倒/r/n向/r/n右/r/n侧/r/n并/r/n推/r/n动/r/n/r/nQ/r/ngL/r/n(1/r/n/r/n/r/nB/r/nθ/r/n时，立方体和小球的速度大小之比/r/nsinθ/r/nD/r/n．/r/n在/r/n前小球的机械能一直减少/r/nF/r/n /r/n力/r/nF/r/n/r/n作用，/r/n沿斜面向下运动，已知拉力/r/nF/r/n/r/n大小/r/n恰好等于物体所受的/r/nF/r/n摩擦力，则物体在运动过/r/n/r/n /r/n/r/n（/r/n2014/r/n·/r/n重/r/n庆一中/r/n5/r/n月/r/n月考）/r/n6. 2013/r/n年/r/n多地/r/n频发，/r/n且有愈演愈烈的趋势，/r/n空气/r/n果/r/n能见度小于/r/n200/r/n米，/r/n应开启机动车的大灯、/r/n雾灯、应/r/n急灯，/r/n将车速控制在/r/n60/r/nkm/h/r/n以下，/r/n并与同道前车保持/r/n50/r/n米的车距；/r/n当能见度小于/r/n100/r/n米时，驾/r/n驶员将车速控制在/r/n40/r/nkm/h/r/n100/r/n/r/n0.1/r/n/r/n0.5/r/ng=10m/s/r/n2/r/n,/r/n若/r/n汽/r/n车/r/n在/r/n天/r/n行/r/n驶/r/n的/r/n速/r/n度/r/n为/r/nv/r/n/r/n36km/h/r/n，/r/n则/r/n刹/r/n车/r/n后/r/n经/r/n过/r/n多/r/n长/r/n时/r/n间/r/n才/r/n会/r/n停/r/n若前车因故障停在车道上，当质量为/r/nm/r/n/r/n1500kg/r/n的后车距已经停止的前车/r/n90m/r/n时紧急刹车，刚好不与前车相撞，则后车正常行驶时的功率为多大？/r/nE4/r/n/r/n实/r/n验/r/n：/r/n探/r/n究/r/n动/r/n能/r/n定/r/n（/r/n2014/r/n·吉林九校联合体第二次摸底）1.测量小物块/r/nQ/r/nP/r/n之间的动摩擦因数的实/r/n验装/r/n置/r/n。/r/nAB/r/n是/r/n半径足够大的光滑四分之一圆弧轨道，与水平固定放置的/r/nP/r/n/r/n板的上/r/nBC/r/nB/r/n点相切，/r/nC/r/nC/r/n′/r/ng/r/n。实验步骤如/r/n①/r/nQ/r/n/r/n②/r/nAB/r/n/r/nR/r/n、/r/nBC/r/n/r/nL/r/n/r/nCC/r/n′/r/n④/r/n重复步骤/r/n③/r/n10/r/n/r/n/r/n/r/ns/r/n。/r/n

/r/nQ/r/n /r/n/r/n /r/n

/r/n /r/n物块/r/nQ/r/n/r/n到达/r/nB/r/n/r/n点时的动能/r/n /r/n物块/r/nQ/r/n/r/n到达/r/nC/r/n/r/n点时的动能/r/n /r/n在物块/r/nQ/r/n/r/n从/r/nB/r/n/r/n运/r/n动到/r/nC/r/n/r/n的/r/n过/r/n，物块/r/nQ/r/n/r/n克服摩擦力做的功/r/nW/r/nf/r/n /r/n物块/r/nQ/r/n/r/n与平板/r/nP/r/n/r/n之间的动摩擦因数/r/n /r/n /r/nμ/r/n/r/n能/r/n /r/n /r/n（/r/n写/r/n出一个/r/n可/r/n能/r/n的原因/r/n可/r/n /r/n/r/n

/r/n甲/r/nD/r/n．在小车运动/r/n过/r/n，对于/r/nM/r/n、/r/nm/r/n/r/n组成的系统，/r/nm/r/n/r/n的重力做正/r/nE/r/nv/r/nE/r/n /r/n⑶若用/r/nB/r/n、/r/nE/r/n两点来研究合外力做功和动能变化的关系，/r/n需要验证的关系式为 /r/n．/r/nO/r/nO/r/n /r/nC/r/nD/r/nE/r/nF/r/ns/r/n乙/r/n（/r/n2014/r/n·江/r/n西师大附中、/r/n鹰潭一中/r/n5/r/n月联考）/r/n3. /r/n某/r/n学/r/n组利/r/n用/r/n的装置验证动/r/n能/r/n将气垫导轨调至水平，安装好实验器材，从图中读出两光电门中心之间的距/r/n离/r/n /r/nd/r/n1/r/n/r/n2/r/n/r/n所用的时间△/r/nt/r/n1/r/n△/r/nt/r/n2/r/n，并从拉力传感器中读出滑块受到的拉力/r/nF/r/n，为了完成实验，还需要直接测量的一个/r/n物/r/n /r/n /r/n（/r/n2014/r/n·江西重点中学协作体第二次联考）/r/n4./r/n/r/n如图甲所示，某同学在做/r/n“/r/n探究功与速度变化的关系/r/n”/r/n1/r/n条橡皮筋的作用下沿木板滑行时，橡皮筋对小车做的功记为/r/nW/r/n./r/n2/r/n/r/n3/r/n/r/n条/r/n…/r/n2/r/nW/r/n /r/nV/r/n的交流电/r/n /r/n /r/n部分/r/n进/r/n量（根据纸带中/r/n /r/nE5/r/n/r/n实/r/n验/r/n：/r/n验/r/n证/r/n机/r/n械/r/n能/r/n守/r/n恒/r/n定/r/n（/r/n2014/r/n·山东日照一中二模）/r/n1./r/n/r/n某实验小组利用图示装置验证机械能守恒定律。实验中先接通电磁打点计时器的低压交流电源，然后/r/n纸带。/r/n打出的纸/r/n带/r/n，/r/n选取纸带上打/r/n/r/n/r/n/r/n/r/n 纸带到打出点/r/n重物减少的重力势/r/n能/r/n/r/nE/r/np/r/n=/r/n /r/n，增加的动能/r/n为/r/n/r/nE/r/nk/r/n=/r/n /r/n算得/r/n的/r/n/r/nE/r/np/r/n和/r/n/r/nE/r/nk/r/n值很接近，则说明：/r/n /r/n一般来说，实验中测得/r/n的/r/n/r/nE/r/np/r/n=/r/n /r/n/r/nE/r/nk/r/n（填“大于/r/n“等于/r/n“小于/r/n /r/n/r/n /r/n下/r/n落/r/n过/r/n，/r/n先/r/n后/r/n通/r/n过/r/n光/r/n电/r/n门/r/n/r/nA/r/n、/r/nB/r/n，/r/n计/r/n时/r/n装/r/n置/r/n测/r/n出/r/n钢/r/n球/r/n通/r/n过/r/n/r/nA/r/n、/r/nB/r/n/r/n的/r/n时/r/n间/r/n分/r/n别/r/n为/r/n/r/nt/r/nA/r/n、/r/nt/r/nB/r/n。/r/n用/r/nh/r/ng/r/n。/r/nD/r/n=/r/n/r/ncm/r/n。/r/n要验证机械能守恒，只要比较/r/n/r/nt/r/n2/r/nD/r/n2/r/n(/r/n/r/nt/r/n2/r/nA/r/nt/r/n2/r/nD/r/n2/r/n(/r/n/r/nt/r/n2/r/nA/r/n

/r/n1/r/n/r/ngh/r/n/r/nt/r/n2/r/nB/r/nt/r/n2/r/nt/r/n2/r/n1/r/n/r/n2/r/ngh/r/n/r/nt/r/n2/r/nB/r/nD/r/n2/r/n1/r/n/r/n/r/n/r/n1/r/n/r/ngh/r/n/r/nt/r/nt/r/n /r/nt/r/nt/r/n /r/nD/r/n2/r/n1/r/n/r/n/r/n/r/n1/r/n/r/n2/r/ngh/r/n/r/nt/r/nt/r/n /r/nt/r/nt/r/n /r/n钢球通过光电门的平均速度/r/n/r/n（选填“/r/n>/r/n”或“/r/n</r/n）/r/n钢球球心通过光电门的瞬时速/r/n度，由此产生的误差/r/n/r/n（/r/n）通过增加实验次数减小。/r/nE6/r/n/r/n功/r/n和/r/n粘/r/n 竖/r/n上/r/n（/r/n2014/r/n·黑/r/n龙江大庆铁人中学模拟）1./r/n，/r/n竖直轻质弹簧，/r/n下端固定在地面，上/r/n端固定一质量为/r/nM/r/n/r/n的木板，/r/n木板上方放一质量为/r/nm/r/n/r/n的物块，/r/n木板和物块间不 /r/n下的力/r/nF/r/n/r/n作用在物块上，/r/n整个系统处/r/n于/r/n状态。/r/n在撤去/r/nF/r/n，/r/n木板和物块向 /r/n长的/r/n过/r/n，下列说法正确的是（/r/n/r/n）/r/n粘/r/n 竖/r/n上/r/nE/r/nB/r/n /r/nA/r/nE/r/nB/r/n /r/nA/r/nD/r/nF/r/n（/r/n2014/r/n·江/r/n苏徐州一中/r/n模拟）/r/n2./r/n如图甲所示，/r/n用竖直/r/n向/r/n/r/nE/r/n/r/nx/r/n/r/nAB/r/n/r/nF/r/n甲/r/n列说法正确的是/r/n /r/nA/r/n．/r/n0/r/n～/r/nx/r/n1/r/n/r/n过/r/n物/r/n体/r/n所/r/n受/r/n拉/r/n力/r/n最/r/nB/r/n．/r/nx/r/n1/r/n～/r/nx/r/n2/r/n过/r/n，物体的加速度先增大后减/r/nC/r/n．/r/n0/r/n～/r/nx/r/n3/r/n过/r/n，物体的动能先增大后减/r/nD/r/n．/r/n0/r/n～/r/nx/r/n2/r/n过/r/n，物体克服重力做功的功率一直增/r/n

/r/n /r/n

/r/n /r/nx/r/n3/r/n/r/n乙/r/n ,/r/n直杆/r/nAB/r/n/r/n与水平面成/r/n/r/n/r/n角固定/r/n,/r/n在/r/n杆上套一质量为/r/nm/r/n的小/r/n滑/r/n块/r/n,/r/n杆/r/n底/r/n端/r/nB/r/n/r/n点/r/n处/r/n有/r/n一弹性挡板/r/n,/r/n杆与板/r/n面/r/n垂/r/n直/r/n,/r/n滑块与挡/r/n板碰撞后原速率返回/r/n./r/n现将滑块拉到/r/nA/r/n/r/n点由/r/n,/r/n与挡板第一次/r/n碰/r/n撞后恰好能上升到/r/nAB/r/n/r/n的中点/r/n设重力加速度为/r/ng/r/n由此可以确定/r/n /r/n滑块下滑和上滑过程加速度的大小/r/na/r/n1/r/n滑块与杆之间动摩擦因数/r/n滑块第/r/nk/r/n/r/n次与挡板碰撞后速度/r/n（/r/n2014/r/n·吉林九校联合体第二次摸底）4./r/n37/r/n0/r/n的粗糙足够长的斜面/r/n/r/noab/r/n/r/n段为曲线，/r/nbc/r/n/r/n段/r/nt/r/n1/r/n=0.1s/r/ns/r/n=0.2m/r/n的距离，/r/ng/r/n10m/s/r/n2/r/n。求：/r/nμ/r/n/r/nE/r/nv/ms/r/nv/ms/r/na/r/nb/r/nc/r/nm/r/n /r/n /r/n /r/n乙/r/n（/r/n2014/r/n·陕/r/n西西工大附中第八次适应性训练）/r/n5./r/n/r/n，/r/n为一传送装置，/r/n其中/r/nAB/r/n段/r/n粗/r/n糙，/r/nAB/r/n/r/nL/r/n＝/r/n0.2/r/n/r/nm/r/n，/r/n动/r/n摩/r/n擦/r/n因/r/n数/r/nμ/r/n＝/r/n0.6/r/n，/r/nBC/r/n、/r/nDEN/r/n/r/n段/r/n均/r/n可/r/n视/r/n为/r/n光/r/n滑/r/nBC/r/n/r/n的/r/n始/r/n、末/r/n端/r/nh/r/n＝/r/n0.1m/r/n的高度差，/r/nDEN/r/nr/r/n＝/r/n0.4/r/n直/r/n线/r/n上/r/n，/r/nCD/r/n/r/n间/r/n的/r/n距/r/n离/r/n恰/r/n能/r/n让/r/n小/r/n球/r/n/r/n通/r/n过/r/n．/r/n在/r/n左/r/n端/r/n竖/r/n直/r/nm/r/n＝/r/n0.2/r/n/r/nkg/r/nA/r/n/r/n点后由/r/n（小球和弹簧不粘连/r/nDEN/r/n/r/nN/r/n（/r/n2014/r/n·/r/n浙/r/n江/r/n杭/r/n州/r/n学/r/n军/r/n中/r/n学/r/n第/r/n九/r/n次/r/n月/r/n考/r/n /r/n1/r/nB/r/nR/r/n=0.45m/r/n/r/nB/r/n4/r/n

/r/n圆弧，它固定在水平平台上，/r/n /r/n/r/nA/r/nB/r/n/r/n端与平台相切。有一小车停在光滑水平面上紧靠平台/r/nM/r/n=1.0kg/r/nL/r/n=1.0m/r/n。现有一/r/n质量为/r/nm/r/n=0.5kg/r/n/r/n的小物体从/r/nA/r/n/r/n点/r/n，滑到/r/nB/r/n/r/n点后顺/r/nB/r/n/r/na/r/n1/r/na/r/n2/r/n物体在小车上滑行过/r/n系统损失的机械能/r/n答/r/n案/r/n与/r/n解/r/n /r/n功/r/n和/r/n功/r/n【全品答案解析】/r/n解析：/r/nA/r/n、开始时，/r/na/r/n、/r/nb/r/n/r/n及传送带均/r/n且/r/na/r/n/r/n不受传送带摩擦力作用，有/r/nm/r/n

/r/n

/r/nA/r/n正确．/r/nB/r/na/r/na/r/n、/r/nb/r/n机械能的增/r/na/r/n/r/n的机械能增加．因为系统重力势能不变，所以摩擦力做功等于/r/nB/r/n正确，/r/nC/r/n错误．/r/nD/r/na/r/n、/r/nb/r/nb/r/n，克服重力的/r/n瞬/r/n时/r/n功/r/n率/r/n/r/nP/r/nb/r/n=mgv/r/n，对/r/na/r/n/r/n有：/r/nP/r/na/r/n=m/r/na/r/ngvsinθ=mgv/r/n，/r/n所/r/n以/r/n重/r/n力/r/n对/r/n/r/na/r/n、/r/nn/r/n/r/n做/r/n功/r/n的/r/n瞬/r/n时/r/n功/r/n率/r/n大/r/n小/r/n相/r/nD/r/nABD/r/n．/r/n【全品答案解析】/r/na/r/nv/r/n /r/n/r/n/r/n/r/nv/r/n /r/n/r/n2/r/n2/r/n2/r/n2/r/n

/r/nv/r/n)/r/n/r/n/r/n/r/n

/r/nv/r/n

/r/n /r/n/r/n/r/nv/r/nx2/r/n＝/r/n

/r/n /r/n

/r/n /r/n2/r/na/r/n，则黑色痕迹的长度/r/nL=x2−x1/r/n＝/r/n

/r/n2/r/na/r/n/r/n1/r/n错误，/r/nC/r/n/r/n正确．/r/nD/r/nQ=fx/r/n/r/n相对/r/n=fL=/r/n2/r/n/r/n

/r/n /r/nD/r/nQ=fx/r/n相对/r/n【全品答案解析】/r/n解析：A/r/nA/r/nA/r/nW/r/nN/r/n+W/r/nG/r/n=0，即得W/r/nN/r/n=-W/r/nG/r/n=-mgLsinα/r/nB/r/n．C、滑动前，/r/nf/r/nf=mgsinθ/r/nθ/r/n，f/r/nC/r/n．D/r/nA/r/n（支持力和摩擦力/r/n【全品答案解析】/r/nA/r/nB/r/n导致木球上浮的/r/n过/r/n水的重心变化不同来选择答案。/r/n【全品答案解析】/r/n解析：本题是轿车要以最大动力上坡，那么要使用“/r/n1/r/nP/r/n/r/n/r/n/r/nFV/r/n/r/n/r/n/r/nF/r/n/r/n/r/n/r/nP/r/n/r/nV/r/n

/r/n

/r/nN/r/n/r/n/r/n

/r/nD/r/n/r/nP/r/n/r/n/r/nFV/r/n/r/n【全品答案解析/r/n（/r/n1/r/n）①/r/n /r/n②/r/n/r/n /r/n（/r/n2/r/n）/r/n/r/n（/r/n3/r/n）/r/nK/r/n/r/n /r/n解析：/r/n（/r/n1/r/n）/r/n

/r/n /r/nm/r/ns/r/n/r/n/r/n/r/n4.76/r/nm/r/ns/r/n/r/n②处的平均速度为：/r/nv=/r/n/r/nx/r/n/r/n

/r/n10/r/nm/r/ns/r/n/r/n10/r/nm/r/ns/r/n1/r/n依次在/r/nv-x/r/n整个/r/n过/r/n功率不变，/r/n故最终做匀/r/n速运动，由/r/n图象可知，/r/n匀速运动的/r/n速度为：v=10m/s，/r/n阻/r/n故有/r/n【全品思路点拨/r/n（1）平均速度等于位移与时间的比值即可求得/r/n（2）/r/nv-x/r/n /r/n动能动/r/n能/r/n定/r/n【全品答案解析】/r/n解析：A/r/nA/r/n；B/r/nE/r/nK/r/n过/r/n机械能的减少量等于阻力的功的大小，/r/n由②图线可知：fh0=Ek0-/r/nk/r/n/r/n1/r/n，/r/n且由①图/r/nk/r/n/r/n/r/n/r/n/r/nk/r/n/r/n/r/n /r/nk/r/n/r/n/r/nEk=Ek0-（mg+f）h=Ek0-（k+1）mg•/r/nk/r/n/r/n2/r/nh0/r/nk/r/n/r/n2/r/nh0/r/nk/r/n/r/n/r/n /r/nk/r/n/r/n/r/n联立解得，Ek/r/nk/r/n/r/n/r/n2/r/n/r/nmgh0，/r/nEP=mgh=/r/nk/r/n/r/n/r/n2/r/n/r/nmgh0/r/nC/r/n．D/r/nh=/r/n

/r/n（k+1/r/nm/r/ng/r/n•/r/n

/r/n1/r/n/r/n=/r/n/r/n

/r/n重力势能为/r/nEP=mg/r/n•/r/n

/r/n/r/nmg/r/nh/r/n0/r/n【全品答案解析】60m/r/n解法/r/n一/r/n：/r/n由/r/n运/r/n动/r/n学/r/n知/r/n识/r/n求/r/nF/r/n/r/n/r/n(/r/nM/r/n/r/n/r/n/r/na/r/n/r/n

/r/nF/r/n/r/n/r/nMg/r/n/r/n/r/n/r/n

/r/n设驾驶员发现脱钩时卡车的速度为/r/nV/r/n由运动学公式/r/nV/r/n/r/n2/r/n/r/n/r/nV/r/n2/r/n/r/n/r/n/r/n设关闭发/r/n后，卡车滑行距离为/r/n

/r/n/r/n/r/n1/r/nMV/r/n/r/n2/r/n /r/nV/r/n /r/n V/r/nS/r/n1/r/n/r/n/r/n/r/n2/r/n/r/ng/r/n/r/n/r/n/r/nM/r/n/r/nL/r/n/r/n/r/nV/r/nS/r/n2/r/n/r/n/r/n/r/n

/r/n/r/n/r/n1/r/nmV/r/n /r/n /r/n

/r/n/r/nS/r/n/r/n/r/n/r/nL/r/n/r/nS/r/n1/r/n/r/n/r/nS/r/n2/r/n/r/n/r/n解/r/n法/r/n二/r/n：/r/n用/r/n动/r/n能/r/n理/r/n求/r/nF/r/n/r/n/r/n(/r/nM/r/n/r/n/r/n/r/nFL/r/n/r/n

/r/n/r/n0/r/n/r/n/r/n1/r/nMV/r/n /r/n对拖车由动能定理有/r/n/r/n/r/nS/r/n/r/n/r/n/r/nS/r/n1/r/n/r/n/r/nS/r/n2/r/n/r/n/r/n

/r/n/r/n0/r/n/r/n/r/n1/r/nmV/r/n /r/n（1）0.15m（2）0.0173s（3）-0.5625J/r/nA/r/nF/r/nN/r/n＝0/r/nF/r/nN/r/n＝0/r/nx/r/n2/r/n=/r/nm/r/n（/r/ng/r/n-/r/nx/r/n/r/n/r/n/r/n1/r/nat/r/n /r/n /r/n /r/nA/r/n做的功：/r/nW/r/n弹/r/n/r/n/r/n/r/n2/r/nF/r/nx/r/n2/r/n/r/n/r/n/r/n/r/n2/r/nE/r/np/r/n2/r/n/r/n/r/n/r/n/r/nW/r/n/r/n弹/r/n/r/n/r/nA/r/n的速度/r/nv/r/n

/r/n/r/n/r/n1/r/nmv/r/n2/r/n

/r/n/r/n/r/nm/r/n2/r/na/r/n(/r/ng/r/n/r/na/r/n)/r/n

/r/n/r/n/r/n9/r/n8/r/nA/r/n由动能定理，/r/nW/r/n/r/n/r/nW/r/nG/r/n/r/n/r/n/r/nW/r/n弹/r/n/r/n/r/nB/r/nA/r/n的作用力所做的功/r/nW/r/n/r/n/r/n/r/n3/r/n（1）/r/n/r/n

/r/n5/r/n/r/n（2）/r/n/r/n

/r/n（/r/n1/r/n）/r/n1/r/n-mgsinα•S-μmgcosα•S=0-/r/n2/r/nv/r/n2/r/nv/r/n /r/n /r/n3/r/n图可得，α=30°时，s=1.25，代入数据得：μ=/r/n/r/nv/r/n2/r/nv/r/n /r/n /r/n5/r/n/r/n把α=60°代入，解得：s=/r/n/r/n /r/n由动能定理得：-μmgcosα•2S=/r/n2/r/nmvt2/r/n2/r/n/r/n5/r/n/r/n解得：vt=/r/n/r/n

/r/n【/r/n全/r/n品/r/n思/r/n路/r/n点/r/n拨/r/n（1）根/r/n据/r/n动/r/n能/r/n定/r/n理/r/n，/r/n求/r/n出/r/n物/r/n体/r/n沿/r/n斜/r/n面/r/n上/r/n升/r/n的/r/n最/r/n大/r/n位/r/n移/r/n/r/ns/r/n/r/n与/r/n斜/r/n面/r/n倾/r/n角θ/r/n的/r/n关/r/n大/r/n位/r/n移/r/ns/r/n与/r/n斜/r/n面/r/n倾/r/n角/r/nθ/r/n的/r/n关/r/n系/r/n表/r/n达/r/n式/r/n，/r/n根/r/n据/r/nα=30°/r/n时/r/n的/r/n数/r/n据/r/n求/r/n出/r/n动/r/n摩/r/n擦/r/n因/r/n数/r/n（/r/n2/r/n）/r/n先/r/n求/r/n出/r/n【全品知识点】/r/n第二定律、/r/n动能定理应/r/n用，弹簧模/r/n型受力分析/r/n问题。高考/r/n考点属/r/n/r/n/r/n2/r/n

/r/n（2）/r/nv/r/n/r/n3/r/ngL/r/n/r/n/r/n /r/n（/r/n1/r/n）/r/n/r/n3/r/ngL/r/n/r/n/r/n /r/n/r/n/r/n /r/nk/r/nA/r/n、/r/nB/r/n/r/n粘连在一起缓慢上移，以/r/nAB/r/n/r/n整体为研究对象，当拉力/r/n /r/n2/r/n/r/nk/r/n(/r/nx/r/n/r/nL/r/n)/r/n/r/n/r/n/r/n2/r/nmg/r/n/r/n2/r/nA/r/n、/r/nB/r/n/r/n不粘连，在恒力/r/nF/r/n/r/n作用下，恰好分离时，根据/r/n第二定律/r/nF/r/n/r/n/r/nk/r/n(/r/nx/r/n/r/nL/r/n)/r/n/r/n2/r/nmg/r/n/r/n/r/n/r/n2/r/nma/r/n以/r/nB/r/n/r/n为研究对象，根据/r/n第二定律/r/nF/r/n/r/n/r/nmg/r/n/r/n/r/nma/r/n/r/n/r/n联立方程①②③④解得：/r/n /r/n2/r/n（/r/n2/r/n）/r/nA/r/n、/r/nB/r/nL/r/nW/r/n/r/n弹/r/nW/r/n/r/n/r/nW/r/n弹/r/n/r/n2/r/nmgL/r/n/r/n0/r/nF/r/n/r/nA/r/n、/r/nB/r/n/r/nv/r/n

/r/n/r/n2/r/nmgL/r/n/r/n/r/n/r/n1/r/n/r/n2/r/nmv/r/n2/r/n2/r/n3/r/ngL/r/n/r/n/r/n /r/n3/r/ngL/r/n/r/n/r/n /r/n /r/n机/r/n械/r/n能/r/n守/r/n恒/r/n定/r/n【全品答案解析】/r/n解/r/n析/r/n：A/r/n、/r/n球从A/r/n上/r/n升/r/n到/r/nB/r/n位/r/n置/r/n的/r/n过/r/n，/r/n先/r/n加/r/n速/r/n，/r/n当/r/n弹/r/n簧/r/n的/r/n弹/r/n力/r/nk△x=mg/r/n时/r/n，/r/n合/r/n力/r/n为/r/n零/r/n，/r/n小/r/n球/r/n从/r/n/r/nA/r/n/r/n上/r/n升/r/n到/r/n/r/nB/r/n/r/n的/r/n过/r/n，/r/n动/r/n能/r/n先/r/n增/r/n大/r/n后/r/n减/r/n小/r/n，A/r/n/r/n错/r/n误/r/n；B/r/n、/r/n小/r/n球/r/n与/r/n弹/r/n簧/r/n组/r/n成/r/n的/r/n系/r/n统/r/n机/r/n械/r/n能/r/n守/r/n恒/r/nA/r/n到/r/nB/r/n过/r/n程/r/n，/r/n弹/r/n簧/r/n弹/r/n性/r/n势/r/n能/r/n减/r/n小/r/n，/r/n小/r/n球/r/n的/r/n机/r/n械/r/n能/r/n增/r/n加/r/n，/r/n离/r/n开/r/nB/r/n继/r/n续/r/n上/r/nC/r/n /r/n /r/nm/r/n

/r/n【全品答案解析】/r/n小球的机械能守恒，小球的速率不断增大．设绳子与竖直方向的夹角为θ，小球运动过程/r/nv/r/n /r/nL/r/nv/r/n得/r/nL/r/n

/r/n/r/n切/r/n，/r/n得/r/n小/r/n球/r/n的/r/n切/r/n向/r/n加/r/n速/r/n度/r/na/r/n切/r/n=gsinθ，θ/r/n一/r/n直/r/n变/r/n小/r/na/r/n切/r/n一直/r/n变/r/n小/r/nB/r/n错/r/n误/r/n．D、/r/n小/r/n球/r/n的/r/nD/r/n：C/r/n【全品知/r/n识点】/r/n机械/r/n能守恒定律；/r/n第二定律/r/n【全品答案解析】/r/nA/r/n、由图乙所示图象可知，在/r/n0-4s内，物块做匀加速直线运动，加速度为：/r/na=/r/n/r/nv/r/n/r/n

/r/n

/r/n /r/n/r/ng/r/n

/r/n/r/n/r/n5/r/n/r/n=0.5/r/nθ=/r/n /r/nA/r/n；B/r/nB/r/nC/r/n恒，故/r/nB/r/n错误；/r/nC/r/nC/r/n点弹簧的弹性势能为：/r/n1/r/n2/r/n

/r/nmv/r/n2/r/n+mgh/r/n/r/n=/r/n /r/n /r/n

/r/n

/r/n6/r/nD/r/n：AC．/r/n【/r/n全/r/n品/r/n知/r/n识/r/n点/r/n】/r/n机/r/n械/r/n能/r/n守/r/n恒/r/n定/r/n律/r/n应/r/n用/r/n考/r/n查/r/n题/r/n，/r/n属/r/n于/r/n能/r/n力/r/n检/r/n测/r/n题/r/n。/r/n在/r/n高/r/n属/r/n于/r/n/r/nII/r/n/r/n级知/r/n识/r/n【全品答案解析】/r/nmg/r/n(/r/nL/r/n/r/nL/r/nsin/r/n/r/n/r/n/r/n1/r/nmv/r/n2/r/n/r/n/r/n/r/n1/r/nm/r/n(/r/nv/r/n/r/n)/r/n2/r/n/r/n /r/n /r/nv/r/n小球的速度，/r/nA/r/n/r/n答案错；由速度分解图可知（图略）/r/nv/r/n/r/n/r/n/r/nsin/r/n/r/nB/r/n/r/n答案正确；根/r/n/r/nD/r/n/r/nBC/r/n【全品答案解析】/r/nC/r/nD/r/nBC．/r/n（/r/n1/r/n）/r/n2s/r/n（/r/n2）450/r/n0/r/n0W/r/n（1/r/n）/r/nV/r/n/r/n/r/nf/r/n2/r/n/r/n/r/nma/r/n/r/n/r/n

/r/nN/r/n/r/nmg/r/n/r/n/r/n0/r/n/r/n/r/na/r/n/r/n/r/n5/r/nm/r/n//r/n/r/nf/r/n2/r/n/r/n/r/nk/r/n2/r/nmg/r/n/r/n/r/n0/r/n据/r/nV/r/nt/r/n/r/n/r/nV/r/n0/r/n/r/nat/r/n有/r/nt/r/n/r/n

/r/n /r/n/r/n据动能定理有/r/n/r/nf/r/n/r/ns/r/n/r/n0/r/n/r/n1/r/nmV/r/n∵/r/nf/r/n2/r/n/r/n/r/n

/r/n /r/n /r/n /r/n∴/r/nV/r/n2/r/n/r/n/r/n2/r/nk/r/n/r/ngs/r/n/r/n2/r/n/r/n0.5/r/n/r/n10/r/n/r/n /r/n∴/r/nV/r/n0/r/n/r/n30/r/nm/r/ns/r/n/r/nF/r/n/r/n/r/nf/r/n1/r/n/r/n/r/n0/r/nf/r/n1/r/n/r/n/r/nP/r/nP/r/n/r/n/r/n∴/r/nP/r/n/r/n/r/nk/r/n1/r/nmgV/r/n0/r/n/r/n/r/n0.1/r/n/r/n1500/r/n/r/n10/r/n/r/n30/r/n/r/n（2/r/n）/r/n /r/n实/r/n验/r/n：/r/n探/r/n究/r/n动/r/n能/r/n定/r/n【/r/n全/r/n品/r/n答/r/n案/r/n解/r/n析/r/n（1）/r/nmgR/r/n1/r/n/r/n

/r/nmgs/r/n；/r/n

/r/nmgR/r/n

/r/nmgs/r/n

/r/n；/r/nR/r/n/r/n/r/n

/r/ns/r/n；/r/n解析：（1）/r/nA/r/nB，由动能定理得：mgR=E/r/nKB/r/n-0，/r/nB/r/n1/r/n2/r/n

/r/n

/r/n2/r/n

/r/nmv/r/n2/r/n

/r/n

/r/nmgs/r/n；/r/nC/r/n1/r/nC/r/n③由/r/nB/r/n到/r/nC/r/n ，由动能定理得：-/r/n2/r/nB/r/nmgs/r/nB/r/n

/r/nC/r/n2/r/nC/r/n

/r/nmv/r/n克服摩擦力做的功/r/n

/r/n；④B/r/n到/r/nC/r/n /r/n

/r/nmgs/r/n

/r/n，则/r/nL/r/n

/r/ns/r/n/r/n；/r/n/r/nμ/r/nB/r/nf/r/n/r/n(/r/ns/r/n6/r/n/r/n/r/ns/r/n4/r/n/r/n（1）AD/r/n⑶/r/nmg/r/n(/r/ns/r/n/r/n/r/ns/r/n/r/n)/r/n/r/n/r/n/r/n1/r/n/r/n(/r/nM/r/n/r/n/r/nm/r/n)/r/nf/r/n/r/n

/r/n/r/ns/r/n/r/n)/r/n2/r/n/r/n/r/n(/r/ns/r/n/r/n/r/ns/r/n/r/n)/r/n2/r/n /r/n /r/n

/r/n /r/n /r/n /r/n⑷将木板调整水平，重复以上步骤，利用/r/nW/r/n/r/n/r/n/r/nmg/r/nBE/r/n/r/n/r/n1/r/n(/r/nM/r/n/r/n/r/nm/r/n)(/r/nv/r/n2/r/n/r/n/r/nv/r/n2/r/n /r/n /r/n解析:（1）A.要使拉力近似等于合力，可将长木板一段垫高，使重力的下滑分量恰好等于/r/nA/r/nB/r/nmg/r/nsin/r/n/r/n/r/n/r/nmg/r/ncos/r/n/r/n，所以/r/n/r/n/r/n/r/ntan/r/n/r/n，平衡一次后/r/n利用/r/nE/r/nDF/r/n

/r/n/r/n/r/ns/r/n6/r/n/r/n/r/n

/r/n/r/n/r/ns/r/n6/r/n/r/n/r/ns/r/n4/r/n/r/n

/r/n/r/ns/r/n2/r/n/r/n

/r/nv/r/n/r/n/r/n/r/ns/r/n3/r/n/r/n/r/n /r/n

/r/n/r/n/r/ns/r/n6/r/n/r/n/r/n

/r/nf/r/n/r/n，/r/n

/r/n/r/n/r/ns/r/n6/r/n/r/n/r/n

/r/n/r/n/r/ns/r/n6/r/n/r/n/r/ns/r/n4/r/n/r/nf/r/n/r/n /r/n /r/n /r/n /r/n /r/n

/r/nmg/r/n(/r/ns/r/n/r/n/r/ns/r/n/r/n)/r/n/r/n/r/n/r/n1/r/nmv/r/n2/r/n/r/n/r/n/r/n1/r/nmv/r/n

/r/n /r/n /r/n /r/nmg/r/n(/r/ns/r/n/r/n/r/ns/r/n/r/n)/r/n/r/n/r/n/r/n1/r/n/r/n(/r/nM/r/n/r/n/r/nm/r/n)/r/nf/r/n/r/n

/r/n /r/n/r/ns/r/n/r/n)/r/n2/r/n/r/n/r/n

/r/n /r/n /r/n /r/n/r/ns/r/n/r/n)/r/n2/r/n /r/n /r/n

/r/n /r/n /r/n /r/nmg/r/nBE/r/n/r/nW/r/n/r/n/r/n/r/n1/r/n(/r/nM/r/n/r/n/r/nm/r/n)/r/nv/r/n2/r/n/r/n/r/n/r/n1/r/n(/r/nM/r/n/r/n/r/nm/r/n)/r/nv/r/n2/r/n，所以/r/nW/r/n/r/n/r/n/r/nmg/r/nBE/r/n/r/n/r/n1/r/n(/r/nM/r/n/r/n/r/nm/r/n)(/r/nv/r/n2/r/n/r/n/r/nv/r/n2/r/n /r/n /r/n /r/n /r/n /r/n /r/n（2/r/n）/r/n【/r/n全/r/n品/r/n答/r/n案/r/n解/r/n析/r/n（1）50.00（2）滑/r/n块/r/n、/r/n挡/r/n光/r/n条/r/n和/r/n拉/r/n力/r/n传/r/n感/r/n器/r/n的/r/n总/r/n质/r/n量/r/n/r/nM/r/n（3）/r/n否/r/ns=73.00cm-23.00cm=50.00cm；/r/nd/r/n1/r/n

/r/n1/r/n根据功能关系需要验证的关系式为/r/n2/r/n

/r/nMv/r/n2/r/n-/r/n2/r/n2/r/n2/r/n

/r/nMv/r/n2/r/n=/r/n1/r/n/r/nM（/r/n1/r/n /r/n1/r/n

/r/n）/r/n2/r/n-/r/n1/r/n/r/nM（/r/nd/r/n/r/n /r/n（/r/n1/r/n）/r/n220/r/n（/r/n2）/r/n（1/r/n）/r/n220V/r/nx/r/n/r/n/r/n/r/n0.0130/r/nm/r/n//r/n

/r/n

/r/n（2）/r/n（3/r/n）/r/nE5/r/n/r/n实/r/n验/r/n：/r/n验/r/n证/r/n机/r/n械/r/n能/r/n守/r/n恒/r/n定/r/n /r/n /r/n /r/n（1）/r/n/r/nE/r/n/r/n/r/nmg/r/n(/r/nx/r/n/r/n/r/n /r/n /r/n /r/n

/r/n；/r/n/r/n

/r/n/r/n/r/nmf/r/n/r/n2/r/n(/r/nx/r/n/r/n/r/n/r/nx/r/n/r/n)/r/n2/r/n

/r/n /r/n /r/n /r/n

/r/n /r/n允许的范围内，重物下落过/r/n机械能守/r/n（2）/r/n解析：（1）从/r/nO/r/n点/r/n到/r/nC/r/n点过/r/n，/r/n重力势能的减小量为/r/n：△E/r/nP/r/n=mg（x/r/n0/r/n+x/r/n1/r/n），/r/n /r/nx/r/n/r/n/r/n /r/nC/r/n/r/n点/r/n的/r/n瞬/r/n时/r/n速/r/n度/r/n：/r/nv/r/nC/r/n

/r/n/r/n/r/n(/r/nx/r/n1/r/n/r/n/r/n/r/nx/r/n2/r/n/r/n)/r/n /r/nm/r/n(/r/nx/r/n/r/n/r/n/r/nx/r/n/r/n)/r/n2/r/n/r/n则动能增量/r/n2/r/n

/r/nmv/r/n2/r/n＝/r/n /r/n /r/n /r/nC/r/nC/r/n/r/n/r/n来说，实验中测得的△E/r/np/r/n大于△E/r/nk/r/n．/r/nII/r/n【全品答案解析/r/n /r/n（/r/n2/r/n）/r/n /r/n /r/n不/r/n（/r/n1/r/n）/r/n（/r/n2/r/n）/r/nD/r/n点零势能位置，则：/r/nmgh/r/n/r/n/r/n1/r/nmv/r/n2/r/n/r/n/r/n/r/n1/r/nmv/r/n2/r/n/r/n，/r/n又/r/nv/r/n/r/n/r/n/r/nD/r/nv/r/n/r/n /r/n，由此可推导出/r/nD/r/n/r/n答案/r/nD/r/n /r/n /r/n /r/n /r/n /r/