英语周报八年级新目标2023－2023第18期答案

英语周报八年级新目标2023－2023第18期答案已经整理完毕，供同学们学习参考，更多英语周报答案，请关注本网站。

【参考范文】To whom it ma concernI am one of your customers. I ordered a set of English short stories on your online store ofAmazon a month ago, but I didn't receive them until yesterday. And much to my disappointmentthe books were so poorly packed up that the package is broken and the cover of one book was tornTo make matters worse, it is not a complete set, for I found one book missingI am sorry to have received such poor service, and I believe I have every right to ask you todeal with this problem. I hope that you either return my money or deliver a new set of books to meBesides, I'd like to be informed of the process of your dealing with my complaintLooking forward to your reply.L

25.(1)正、负粒子的比荷之比是1:3(2)正、负粒子在磁场中运动的半径大小分别是L和(3)两粒子先后进入电场的时间差是3zL[(1)设粒子进磁场方向与边界夹角为0,粒子在水平方向做匀速直线运动,则:L(1分)沿电场线的方向:F=m(1分)vy=at(1分)又:1==(分)tang联立得:1:3(1分)m1m2tan60°tan30(2)粒子在电场中的偏转量:y=2t(1分)L=vt所以2=2(1分)L-2an30°(1分)2=2tan60°(1分)两粒子离开电场位置间的距离:d=y1+y2=23.(1分)磁场中圆周运动速度:v=(1分)ine磁场中圆周运动速度:=(1分)SI所以:v2√3sin60sing由洛伦兹力提供向心力得:qB=(1分)得:r=9B,所以√3(1分)根据题意作出运动轨迹,两粒子相遇在P点,由几何关系可得:2r1=dsin60°(1分)2r2=dsin30°(1分)联立解得:r1√L(1分(3)粒子在磁场中运动的周期:T=2(1分)两粒子在磁场中运动时间均为半个周期,则:==25x2(1分)4voxn=5(1分)12两粒子在磁场中运动时间均为半个周期,则:t11分4兀2=√3xLo12(1分)由于两粒子在电场中时间相同,所以进电场时间差即为磁场中相遇前的时间差:/srl△t=t1-t=(1分)6

以上就是英语周报八年级新目标2023－2023第18期答案，更多英语周报答案请关注本网站。