17.
如图所示,粗糙绝缘水平地面AP与光滑绝缘半圆弧竖直轨道PQ相切于P点,PQ右侧有水平向右的匀强电场,场强大小
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmi%3EE%3C%2Fmi%3E%3Cmo%3E%3D%3C%2Fmo%3E%3Cmfrac%3E%3Cmrow%3E%3Cmi%3Em%3C%2Fmi%3E%3Cmi%3Eg%3C%2Fmi%3E%3C%2Fmrow%3E%3Cmrow%3E%3Cmi%3Eq%3C%2Fmi%3E%3C%2Fmrow%3E%3C%2Fmfrac%3E%3C%2Fmath%3E)
, 圆轨道半径为R,AP长度
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmsub%3E%3Cmrow%3E%3Cmi%3EL%3C%2Fmi%3E%3C%2Fmrow%3E%3Cmrow%3E%3Cmn%3E1%3C%2Fmn%3E%3C%2Fmrow%3E%3C%2Fmsub%3E%3Cmo%3E%3D%3C%2Fmo%3E%3Cmn%3E5%3C%2Fmn%3E%3Cmi%3ER%3C%2Fmi%3E%3C%2Fmath%3E)
。A点左侧有一弹射装置,A点右侧B处静置一质量为m带电荷量为+q的滑块C,AB长度
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmsub%3E%3Cmrow%3E%3Cmi%3EL%3C%2Fmi%3E%3C%2Fmrow%3E%3Cmrow%3E%3Cmn%3E2%3C%2Fmn%3E%3C%2Fmrow%3E%3C%2Fmsub%3E%3Cmo%3E%3D%3C%2Fmo%3E%3Cmi%3ER%3C%2Fmi%3E%3C%2Fmath%3E)
。现用此装置来弹射一质量为m的滑块D,滑块D在A点获得弹簧储存的全部弹性势能后向右运动,到达B点与C发生完全弹性碰撞(碰撞过程C电荷量不变),碰撞后滑块C继续向右运动到P点进入光滑圆轨道,通过最高点Q后水平抛出。若滑块C运动到Q点恰好不受轨道压力,滑块C、D与地面的动摩擦因数均为
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmtext%3E%CE%BC%3C%2Fmtext%3E%3Cmo%3E%3D%3C%2Fmo%3E%3Cmn%3E0%3C%2Fmn%3E%3Cmn%3E.%3C%2Fmn%3E%3Cmn%3E5%3C%2Fmn%3E%3C%2Fmath%3E)
, 不计空气阻力,滑块都可看作质点,弹簧始终在弹性限度内。试求:
![](//tikupic.21cnjy.com/2022/07/27/5f/1f/5f1f27a0b477f401463c30a77e6fde34_383x164.png)