小学、初中、高中各种试卷真题知识归纳文案合同PPT等免费下载www.doc985.com专题07动量定理动量守恒定律目录01动量定理的理解及应用······················································································2考向一动量定理的应用················································································································2考向二利用动量定理处理流体(变质量)问题············································································1002动量守恒定律的理解及应用············································································14考向一碰撞模型··························································································································14考向二爆炸反冲人船模型·······································································································18小学、初中、高中各种试卷真题知识归纳文案合同PPT等免费下载www.doc985.com01动量定理的理解及应用考向一动量定理的应用1．（2023·福建·高考真题）（多选）甲、乙两辆完全相同的小车均由静止沿同一方向出发做直线运动。以出发时刻为计时零点，甲车的速度—时间图像如图（a）所示，乙车所受合外力—时间图像如图（b）所示。则（）A．0~2s内，甲车的加速度大小逐渐增大B．乙车在t=2s和t=6s时的速度相同C．2~6s内，甲、乙两车的位移不同D．t=8s时，甲、乙两车的动能不同【答案】BC【详解】A．由题知甲车的速度一时间图像如图（a）所示，则根据图（a）可知0~2s内，甲车做匀加速直线运动，加速度大小不变，故A错误；B．由题知乙车所受合外力一时间图像如图（b）所示，则乙车在0~2s内根据动量定理有I2=mv2，I2=S0~2=2N·s,乙车在0~6s内根据动量定理有I6=mv6，I6=S0~6=2N·s,则可知乙车在t=2s和t=6s时的速度相同，故B正确；C．根据图（a）可知，2~6s内甲车的位移为0；根据图（b）可知，2~6s内乙车一直向正方向运动，则2~6s内，甲、乙两车的位移不同，故C正确；D．根据图（a）可知，t=8s时甲车的速度为0，则t=8s时，甲车的动能为0；乙车在0~8s内根据动量定理有I8=mv8，I8=S0~8=0,可知t=8s时乙车的速度为0，则t=8s时，乙车的动能为0，故D错误。故选BC。2．（2021·北京·高考真题）如图所示，圆盘在水平面内以角速度ω绕中心轴匀速转动，圆盘上距轴r处的P点有一质量为m的小物体随圆盘一起转动。某时刻圆盘突然停止转动，小物体由P点滑至圆盘上的某点停止。下列说法正确的是（）小学、初中、高中各种试卷真题知识归纳文案合同PPT等免费下载www.doc985.comA．圆盘停止转动前，小物体所受摩擦力的方向沿运动轨迹切线方向B．圆盘停止转动前，小物体运动一圈所受摩擦力的冲量大小为C．圆盘停止转动后，小物体沿圆盘半径方向运动D．圆盘停止转动后，小物体整个滑动过程所受摩擦力的冲量大小为【答案】D【详解】A．圆盘停止转动前，小物体随圆盘一起转动，小物体所受摩擦力提供向心力，方向沿半径方向，故A错误；B．圆盘停止转动前，小物体所受摩擦力，根据动量定理得，小物体运动一圈所受摩擦力的冲量为，大小为0，故B错误；C．圆盘停止转动后，小物体沿切线方向运动，故C错误；D．圆盘停止转动后，根据动量定理可知，小物体整个滑动过程所受摩擦力的冲量为，大小为，故D正确。故选D。3...