如图，ABC为绝缘轨道，AB部分是半径R=40cm的光滑半圆轨道，P是半_爱下问搜题

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问题问答题

如图，ABC为绝缘轨道，AB部分是半径R=40cm的光滑半圆轨道，P是半圆轨道的中点，BC部分水平，整个轨道处于E=1×10³V/m的水平向左的匀强电场中，有一小滑块质量m=40g，带电量q=1×10^-4C，它与BC间的动摩擦因数µ=0.2，g取10m/s²，求：

（1）要使小滑块能运动到A点，滑块应在BC轨道上离B多远处静止释放？

（2）在上述情况中，小滑块通过P点时，对轨道的压力大小为多少？

答案

（1）最高点处重力充当向心力，由向心力公式可得：

mg=m

V2

R

------（1）

由动能定理可得：

EqL-mg2R-μmgL=

1

2

mv²------（2）

联立（1）（2）解得：

L=20m；

（2）由动能定理可知

Eq（L+R）-mgR-μmgL=

1

2

mv_P²------------（3）

而在P点轨道对小于的支持力与电场力的合力充当向心力，

F-Eq=m

v

2P

R

------（4）

联立（3）、（4）可解得P点压力F=1.5N．

完形填空

I truly feel that my mother led me here, to Morzaine, and to my future as happy wife and business woman. When Mum ____ in October 2007, I was a cook. In December that year while I was working for a wedding, a pearl necklace Mum had left me ____. I was distraught(忧心如焚的). Some days later, I was ____ that a guy who was working with us that day “could probably have made a fortune ___ the necklace he found.” ____， he returned it. Hearing how I'd ____Mum for six months before her death, he said，” Christmas is going to be ___ —why not go out to the Alps for a couple of weeks？”
I come to Morzaine，a small，friendly village in the Alps and ____ fell in love with it. What was ____ to be a stopgap (权宜之计) trip turned into a new life. I kept travelling between London and here and felt ____ than I had in months.In December 2008, I was ____ as a hotel manager and moved here full time.
A month later, I met Paul, who was traveling here. We fell in love. In the beginning, I didn't want to discuss ____， because the sadness of losing Mum ____ felt great. Paul understood that and never __49__ me but, by summer, we got married. A year later, we used his saving, and the money from the sale of Mom's house, to build our own ____.
We want to give our guests a ____ feeling, so each room is themed(以……为主题) around memories from our lives. There are also style to remind me of Mom —a tiny chair which ___ be in her bedroom is set in one room.
We are having a wonderful life Mum ____ naturally part of it, ____ there's no way we would be here if it wasn't for the ____ she gave me. I know she's here in spirit, keeping an eye on us.

B．disappeared

A．suddenly	B．finally
C．nearly	D．immediately

D．interrupted

单项选择题案例分析题

张东升是平山矿业公司露天矿机修车间的一位维修钳工，正式技工学校毕业，今年38岁，年富力强。他干劲大，手艺强，肯负责，人缘好，还带了三名学徒工做徒弟，同事和上级都挺喜欢他，车间主任李明更视他为骨干，常让他代表自己去矿上或公司开干部会，大家都说李主任的接班人非他莫属。

今天是周一，他正赶上白班，忽然听说李主任心脏病犯了，已经住进职工医院。李主任德高望重，深受大家敬爱，就是身体不行。这回住院，人人都盼望他早日康复，以为又象往常那样，过几天就出院上班。不料傍晚传来噩耗，李主任病重，经抢救无效，已病逝在医院中。大家都很悲痛，纷纷去向李师母表示悼念和慰问。

次日一早，分管人事的周副矿长来电话，要张东升暂时代理车间主任，行使权力，不使工作受损，还特别关注正在抢修的一台装载机，问何时能修好，这可是矿上等着要用的急活。张东升答应周四中午前一定修好交用。

星期三上午，周副矿长把张东升召去，正式通知他公司已任命他继任车间主任，并表示了祝贺和期望。然后张东升就匆匆赶回车间，参加突击抢修那台装载机去了。任务很重，他不放心，又跟着夜班工人继续干到晚上九点多，再三叮嘱夜班班长抓紧工作，才回家休息。

周四早上，张东升特别早到班，发现昨晚矿上又有四辆自卸式载重卡车送来待修，而那台装载机还未修好。张东升忙把全车间白班职工召在一起，说明了面临的修车任务如何重要、迫切和艰巨，号召大家化悲痛为力量，群策群力，尽快完成任务。工人们纷纷表态要努力干活，如期修好这批车辆。

张东升略感松了一口气，就上备品库去检查库存是否足以应付这批抢修任务。这时，露天采掘队来电话，说他们的一台主力设备，32吨自卸卡车抛锚在现场，要求派人去抢修。张东升知道如今人人手头的活都又多又紧，就自己背起工具箱，下露采现场去抢修了。

待他修好那台自卸卡车，回到车间，已经快中午了。他发现车间里乱遭遭一片：四辆待修自卸车中有三辆在停工待料，忙问这是咋回事。工人们说已故李主任以前定下的规矩，备件要主任签过字才能领取。这时，矿上又有两台故障车送到待修。张东升刚办完接车手续，周副矿长又来电话要装载机了。听说还没修好，周矿长老大不快，埋怨活抓得不紧，并强调这会给矿上带来很大损失。刚放下电话，公司常务副经理又打来电话，让他马上去总部出席紧急干部会议，

本来张东升知道自己被正式提升为车间主任，还挺高兴，也颇有信心当好这个主任，如今想法好像有些变了。他怀疑这提升对自己究竟是不是一件好事，对能否胜任主任一职，也变得不太有把握了。

如果张东升想改变目前的状况，那么（）做法能够帮助他。

A.迅速建立相关制度

B.委派一个人做自己的助手，协调各个组的工作

C.提供给员工最大的支持，并不是帮助他们干活

D.其上做法都可以