摘要:23. 如图所示.水平放置的平行板电容器.原来两极板不带电.上极板L=0.1m.两板间距离d=0.4cm.有一束由相同粒子组成的带正电粒子流.以某一初速度v0从两板中央平行于极板射入.由于重力的作用.粒子恰能落到下板中点O处.已知粒子质量为m=2× 10-4kg.电荷量q=1×10-8C.电容器的电容C=1×10-4F.g取10m/s2 不记空气阻力. (1) 求粒子入射速度vo的大小, (2) 若在两极板间加上适当的恒定电压.要让以速度vo的上述带电粒子.恰好做匀速直线运动从两板间飞出.试确定下极板的带电性质和电荷量. 24如图甲所示.在倾角的足够长斜面上.有一带帆的滑块从静止开始沿斜面下滑.风帆平面垂直于斜面和下滑方向.滑块和风帆的总质量m==2 kg.滑块与斜面间的动摩擦因数为.帆受到的空气阻力与滑块下滑的速度的平方成正比.即.滑块从静止开始沿斜面下滑的速度图象如图乙所示.图中曲线OA是滑块的速度图线.图中直线OB是时刻的速度图线的切线.g取10 m/s2.求: (1)动摩擦因数, (2)比例系数k.

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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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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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