问题 多选题

如图所示,在固定的圆锥形漏斗的光滑内壁上,有两个质量相等的小物块A和B,它们分别紧贴漏斗的内壁,在不同的水平面上做匀速圆周运动.则以下叙述正确的是(  )

A.物块A的线速度大于物块B的线速度

B.物块A的角速度大于物块B的角速度

C.物块A对漏斗内壁的压力大于物块B对漏斗内壁的压力

D.物块A的周期大于物块B的周期

答案

对A、B两球进行受力分析,两球均只受重力和漏斗给的支持力FN.如图所示.

设内壁与水平面的夹角为θ.

根据牛顿第二定律有:mgtanθ=m

v2
r

则v=

grtanθ
,半径大的线速度大,所以A的线速度大于B的线速度.

ω=

v
r
=
gtanθ
r
,知半径越大,角速度越小,所以A的角速度小于B的角速度.

T=

ω
,则角速度越大,周期越小,所以A的周期大于B的周期.

支持力FN=

mg
cosθ
,知物块A对漏斗内壁的压力等于物块B对漏斗内壁的压力.

故AD正确,B、C错误.

故选AD.

完形填空
I returned home to spend the holiday with my mom excitedly. I was looking forward to sitting down on the sofa, watching TV and      until midnight with her.
However, things weren’t as I expected. Not long       I arrived home, mom got a phone call. One of her friends      her to play cards. She gladly accepted the invitation and went at once. I thought she didn’t like me.
During the following days, I deliberately(故意的)        to speak to her. Whenever she spoke to me, I just stood in silence. But later I began to feel       . Sometimes I really wanted to say sorry to her,       when I saw her making delicious food or buying me     favorite snacks. Maybe she felt sorry for    she had done that night. I began to think that I should do something to make the things    
At the end of the holiday, I began to help with some     from making the bed to cleaning the house, I did       I could when mom wasn’t around. When she returned, she smiled happily.
On the     day,she insisted (坚决要求) on driving me to the bus station. At first we said nothing, then mom said, “Sorry for that night. You know that you mean       than anything to me .”I couldn’t say a word as I tried to    back the tears. Before getting on the bus, I finally said sorry to her. Mom smiled, and there were tears        her eyes. But I knew they were tears of happiness.
小题1:
A.speakingB.talkingC.sayingD.telling
小题2:
A.whenB.beforeC.untilD.after
小题3:
A.toldB.askedC.invitedD.ordered
小题4:
A.refusedB.startedC.likedD.wanted
小题5:
A.happyB.sadC.surprisedD.excited
小题6:
A.actuallyB.totallyC.especiallyD.really
小题7:
A.hisB.myC.herD.our
小题8:
A.whatB.whenC.whyD.that
小题9:
A.rightB.wrongC.busyD.awful
小题10:
A.homeworkB.cookingC.houseworkD.exercise
小题11:
A.everythingB.somethingC.nothingD.anything
小题12:
A.firstB.nextC.thirdD.final
小题13:
A.mostB.more C.bestD.better
小题14:
A.giveB.hold C.returnD.get
小题15:
A.onB.outC.inD.over
综合题

(15分)【中外历史人物评说】

材料一 “我在这场战争中的最高目标是拯救联邦,既不是保全奴隶制,也不是摧毁奴隶制。如果我能拯救联邦而不解放任何一个奴隶,我愿意这样做;如果为了拯救联邦需要解放一部分奴隶而保留另一部分,我也愿意这样做。”

——1862年8月22日林肯给《纽约论坛报》编辑的一封信

材料二 4年前我就任总统时,同胞们的思想都焦急地集中在日益迫近的内战上。大家都害怕内战,都想避免内战。当我在这个地方发表就职演说,竭尽全力想不经过战争来拯救联邦时,叛乱分子却在这个城市里图谋不经过战争来毁灭联邦──企图以谈判方式解散联邦并分割财产。双方都表示反对战争,但一方宁愿发动战争也不愿让国家生存,而一方则宁可接受战争也不肯让国家灭亡,于是战争就爆发了。

——林肯连任就职演说(1865年3月4日)

材料三 林肯总统在大势之所趋和人心之所向都不许再拖以前,是从来不冒险朝前走一步的。但是,只要“old Abe”[“老阿伯”(阿伯拉罕·林肯)]一旦相信这样一种转折点已经到来,他就会采取某种突然的、尽可能不声不响的行动而使朋友和敌人都同吃一惊。

——马克思《美国近事》(1862年2月26日左右)

材料四 2008年11月5日,网易新闻登载了一篇题为“林肯的狡猾:‘解放黑奴’只是为了战争胜利”的文章,称林肯为“狡猾保守的废奴主义者”。

请回答:

(1)结合材料一、二、三及所学知识,回答林肯对美国的贡献有哪些?并分析林肯取得如此功绩的主观因素有哪些?(9分)

(2)请谈谈你对材料四所持观点的看法。(6分)