摘要:18.如图所示.在光滑水平面上有一质量M=0.4kg滑槽.滑槽面上的AB段是半径R=0.4m的光滑1/4圆弧.与B点相切的水平表面BC段粗糙.长L=3m.动摩擦因数μ=0.4.C点的右表面光滑.右端连有一弹簧.现有一质量m=0.1kg的小物体在距A点高为H=0.6m处由静止自由落下.恰沿A点滑入圆弧面.滑到B点时滑槽刚好与墙壁碰撞.假设滑槽与墙碰撞后在极短时间内速度减为0.但不粘连.求: (g=10m/s2) (1)小物体滑到B点时.小物体和滑槽碰墙前的速度分别多大 (2)小物体最终与C点的距离

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书面表达(共1小题,满分25分)

假如你是高中三年级的学生李华,你在学校组织了一项“有烦恼向谁说”的调查活动。请用英语给报社编辑写一封信,反映相关情况。内容包括:调查结果(如图所示)、持相应想法的理由及你对调查结果的看法。

注意:1. 信的开头和结尾已经给出。

2. 词数120词左右。

Dear Editor,

     I am a Senior Three student. Recently we have carried out a survey — “To whom do you do when in trouble?” The results are as follows.

                                                                     

                                                                     

                                                                    

                                                                     

                                                                    

                                                                    

                                                                      

                                                       Yours sincerely,

                                                              Li Hua

 

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