9.
(2022·云南模拟)
如图甲所示,光滑水平面上静止一左侧带有固定挡板的长木板C,其质量M=2kg。木板C上放置有质量
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmsub%3E%3Cmrow%3E%3Cmi%3Em%3C%2Fmi%3E%3C%2Fmrow%3E%3Cmrow%3E%3Cmi%3EA%3C%2Fmi%3E%3C%2Fmrow%3E%3C%2Fmsub%3E%3Cmo%3E%3D%3C%2Fmo%3E%3Cmsub%3E%3Cmrow%3E%3Cmi%3Em%3C%2Fmi%3E%3C%2Fmrow%3E%3Cmrow%3E%3Cmi%3EB%3C%2Fmi%3E%3C%2Fmrow%3E%3C%2Fmsub%3E%3Cmo%3E%3D%3C%2Fmo%3E%3Cmn%3E0%3C%2Fmn%3E%3Cmn%3E.%3C%2Fmn%3E%3Cmn%3E5%3C%2Fmn%3E%3Cmtext%3Ek%3C%2Fmtext%3E%3Cmtext%3Eg%3C%2Fmtext%3E%3C%2Fmath%3E)
的物体A和物块B (可视为质点)。已知物体A与木板C间的动摩擦因数
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmsub%3E%3Cmrow%3E%3Cmtext%3E%CE%BC%3C%2Fmtext%3E%3C%2Fmrow%3E%3Cmrow%3E%3Cmn%3E0%3C%2Fmn%3E%3C%2Fmrow%3E%3C%2Fmsub%3E%3C%2Fmath%3E)
=0.3。A的右端与木板C右端对齐, A的左端与木板C的挡板间的距离x=0.25m;物块B放在物体A的右端。现长木板C在水平恒力F的作用下从静止开始向右做匀加速直线运动,经过0.5s后物体A与C上的挡板发生碰撞并粘在一起(碰撞时间极短),在碰前的过程中A的速度与时间图像如图乙所示。取重力加速度g= 10m/s
2 , 最大静摩擦力等于滑动摩擦力。求∶
![](//tikupic.21cnjy.com/2022/02/17/3e/97/3e97be0f7eaaa673202c81526a12c445.png)