在香港海洋公园的游乐场中,有一台大型游戏机叫“跳楼机”.参加游戏的游客被安全带固

题型:问答题

问题:

在香港海洋公园的游乐场中,有一台大型游戏机叫“跳楼机”.参加游戏的游客被安全带固定在座椅上,由电动机将座椅沿光滑的竖直轨道提升到离地面40m高处,然后由静止释放.座椅沿轨道自由下落一段时间后,开始受到压缩空气提供的恒定阻力而紧接着做匀减速运动,下落到离地面4.0m高处速度刚好减小到零,这一下落全过程经历的时间是6s.求:(取g=10m/s2

(1)座椅被释放后做自由下落的末速度v

(2)座椅被释放后做自由下落的高度h

(3)在匀减速运动阶段,座椅的加速度大小是多少.

考点:匀变速直线运动的位移与时间的关系自由落体运动
题型:问答题
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When I was young, I liked to play jokes on people I knew, especially on my parents and friends. One day my mother was   1  and I was playing with my younger brother Tony. Suddenly I ran to my mother and said, “Tony fell from the open window!” She was very   2  and ran out of the kitchen. Then I said, “Don’t worry. I’m just   3 .” And my mother shouted at me, “If you do it   4 , I’ll hit you.”
One day I went swimming with my   5  in the sea. I wanted to play a joke on them. In the beginning, I went swimming   6 , and I called out, “Help!” All my friends came to help me, only to   7  that I was joking. But the next time I wasn’t joking. I was so   8  that I swam in deep water. I tried my best to call my friends for help, but this time nobody came to help me.   9 , they found I was telling the truth. They came and saved my life. They took me to the hospital. This is the best   10  in my life. From then on, I haven’t joked on anyone.
小题1:
A.cookingB.sleepingC.writingD.running
小题2:
A.angryB.worriedC.sorryD.excited
小题3:
A.smilingB.sayingC.playingD.joking
小题4:
A.nowB.thenC.againD.once
小题5:
A.friendsB.classmatesC.brothersD.parents
小题6:
A.fastB.slowlyC.wellD.alone
小题7:
A.findB.understandC.sayD.think
小题8:
A.carefulB.carelessC.fastD.slow
小题9:
A.At firstB.In the endC.Since thenD.At that time
小题10:
A.timeB.sportC.lessonD.day
题型:问答题

需要单程票报销凭证的乘客,原则上在购买车票后凭所购付费车票在()索取报销凭证。

A.出站售票/问询处

B.进站售票/问询处

C.出站充值窗口

D.进站充值窗口

题型:问答题

以下细胞中不受HIV侵犯的是()

A.CD4+T细胞

B.CD8+T细胞

C.B细胞

D.树突状细胞

E.巨噬细胞

题型:问答题

重庆一号线地铁列车司机室顶板设置()个司机室顶灯,用于司机室照明。

A.4

B.5

C.6

D.7

题型:问答题

以下哪种情形代表了薪酬部门内部控制的薄弱环节

A.薪酬部门人员要轮换其职务。
B.薪金支票由员工的直接管理员发放。
C.薪金记录要每季度与税收报告核对。
D.时间记录职能是独立于薪酬部门的。

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