6．(2009·安徽·15)2009年2月11日，俄罗斯的“宇宙-2251”卫星和美国的“铱-33”卫星在西伯利亚上空约805 km处发生碰撞．这是历史上首次发生的完整在轨卫星碰撞事件．碰撞过程中产生的大量碎片可能会影响太空环境．假定有甲、乙两块碎片，绕地球运动的轨道都是圆，甲的运行速率比乙的大，则下列说法中正确的是　　　　　　　　　　　　 (　)

A．甲的运行周期一定比乙的长

B．甲距地面的高度一定比乙的高

C．甲的向心力一定比乙的小

D．甲的加速度一定比乙的大

解析　根据万有引力提供向心力有

＝m＝m(R+h)＝ma.

v＝ 　T＝2π 　a＝

由于v_甲>v_乙，所以甲离地面的高度小于乙离地面的高度，甲的周期小于乙的周期，甲的向心加速度比乙的大．由于甲、乙质量未知，所受向心力大小无法判断．综上所述正确选项为D项．

答案　D

5．(2009·福建·14)“嫦娥一号”月球探测器在环绕月球运行过程中，设探测器运行的轨道半径为r，运行速率为v，当探测器在飞越月球上一些环形山中的质量密集区上空时(　)

A．r、v都将略为减小

B．r、v都将保持不变

C．r将略为减小，v将略为增大

D．r将略为增大，v将略为减小

解析　月球探测器环绕月球运行，万有引力提供向心力G＝，当到达质量密集区时，万有引力增大，探测器将“向心”运动，半径将减小，速度增大，故C对．

答案　C

4．(2009·浙江·19)在讨论地球潮汐成因时，地球绕太阳运行轨道与月球绕地球运行轨道可视为圆轨道．已知太阳质量约为月球质量的2.7×10⁷倍，地球绕太阳运行的轨道半径约为月球绕地球运行的轨道半径的400倍．关于太阳和月球对地球上相同质量海水的引力，以下说法正确的是　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　 (　)

A．太阳引力远大于月球引力

B．太阳引力与月球引力相差不大

C．月球对不同区域海水的吸引力大小相等

D．月球对不同区域海水的吸引力大小有差异

解析　由万有引力定律F＝可知，F∝，太阳与月球对相同质量海水的引力之比＝1.687 5×10²，故A对；月球与不同区域海水的距离不同，故吸引力大小有差异，D对．

答案　AD

3．(2009·宁夏·15)地球和木星绕太阳运行的轨道都可以看作是圆形的．已知木星的轨道半径约为地球轨道半径的5.2倍，则木星与地球绕太阳运行的线速度之比约为　　　　　 (　)

A．0.19　　B．0.44　　C．2.3　　D．5.2

解析　由万有引力定律和圆周运动知识G＝m可得v＝ ，所以木星与地球绕太阳运动的线速度之比＝ ＝0.44，B正确．

答案　B

2．(2009·广东·5)发射人造卫星是将卫星以一定的速度送入预定

轨道．发射场一般选择在尽可能靠近赤道的地方，如图1所示，这

样选址的优点是，在赤道附近　　　　　　　　　　　　　　　　　　　　　　　 (　)

A．地球的引力较大

B．地球自转线速度较大　　　　　　　　　　　　　　　　　　　　　 图1

C．重力加速度较大

D．地球自转角速度较大

解析　若将地球视为一个球体；则在地球上各处的引力大小相同，A错；在地球上各处的角速度相同，D错；在地球的表面附近，赤道的半径较大，由公式v＝ωr可知，半径越大线速度越大，B对；在赤道上的重力加速度最小，C错．

答案　B

1．(2009·山东·18)2008年9月25日至28日，我国成功实施了“神舟”七号载人航天飞行并实现了航天员首次出舱．飞船先沿椭圆轨道飞行，后在远地点343千米处点火加速，由椭圆轨道变成高度为343千米的圆轨道，在此圆轨道上飞船运行周期约为90分钟．下列判断正确的是　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　 (　)

A．飞船变轨前后的机械能相等

B．飞船在圆轨道上时航天员出舱前后都处于失重状态

C．飞船在此圆轨道上运动的角速度大于同步卫星运动的角速度

D．飞船变轨前通过椭圆轨道远地点时的加速度大于变轨后沿圆轨道运动的加速度

解析　由于变轨过程中需点火加速，所以变轨后飞船的机械能增大，选项A错误；宇航员出舱前后均与飞船一起做匀速圆周运动，万有引力提供了做圆周运动的向心力，因此出舱前后航天员都处于失重状态，选项B正确；飞船在圆轨道上运行的周期为90分钟，而同步卫星的周期为24小时，所以飞船在圆轨道上运动的角速度大于同步卫星的角速度，选项C正确；只要在同一点受到的万有引力相同，由牛顿第二定律得a＝＝，即加速度相同，选项D错误．

答案　BC

第二节：书面表达(15分)

　　　 学校要举办英语晚会，现请你以学生会的名义发一份英语书面通知，欢迎全校师生参加。内容提要：

　　　 晚会时间：下周五晚7：30-10：00

　　　 晚会地点：学生食堂

　　　 晚会内容：英语故事、歌曲、诗歌和短剧等。届时还邀请在本校工作的加拿大教师布朗夫妇及子女参加晚会，他们将要表演精彩的节目。

　　　 希望大家按时到。

　　　 注意：1．词数：100左右。

2．要包括所有要点，但不要逐条翻译；注意使用连词等，以使上下文连贯；还要注意格式。

___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

　　　 Answer sheet

　　　 听力材料Listening materials

(Text 1)

W: Something is wrong with my car．How can I go to the concert?

M: Don't worry, I'll come and pick you up in my car．

(Text 2)

M: It was so nice of Peter to offer to take us to the airport．

W: Wouldn't it be more convenient if we just take a taxi?

(Text 3)

M: There used to be a lot of fish in the lake when its water was clean．

W: But there are very few now．

(Text 4)

M: It's unfair．Everybody has got three days off, but I only have one day．

W: Yes, but everybody has finished his task while you haven't finished half．

(Text 5)

M: How did you manage to get the work finished on time?

W: It was easy with Joan’s help．

(Text 6)

W: What do you think? Am I OK?

M: Well, I want to do some tests．

W: How soon will I get the results?

M: Oh, you'll have the results before you leave the office, and here is some medicine that I believe will help you．

(Text 7)

W: Hello, haven't seen you for ages．Have you moved away?

M: No．I was so busy, and had almost no time to meet friends．

W: What are you busy with? Preparing for a test?

M: I'm supposed to take a national mathematics test next week．

W: What a surprise! Have you prepared well enough?

M: Not really．I still have some questions which I need to ask teachers about．

W: Well．Then do your best, and I wish you good luck．

(Text 8)

M: Hello, 75610．

W: Hello, Dennis．Are you still coming to lunch on Saturday?

M: Well, you know I'm having a party in the evening．I'm going shopping for it in the morning, so there isn’t much time．

W: Never mind．Well, come to tea on Sunday．

M: There's a special TV program I want to watch．I think it's on at about 5 : 30．

W．That's all right．Come and watch it here．I'll make one of my chocolate cakes．

M．Who can resist your cakes? Fine, tea on Sunday then．

W: Good and good luck on Tuesday．I hope you get your salary raised．

M．Thank you．

(Text 9)

W: You won't believe what happened to me yesterday!

M: What happened to you?

W: I woke up at seven thirty in the morning…

M: Seven thirty? So early? I mean．．．

W: Yes．But listen up．I had breakfast and went to my car, right? Well, the car didn't start．So I walked all the way to Baker Street to take a taxi．

M．A taxi? On Sunday morning ? Did you find one?

W: Of course not．So I took the bus．

M: But I don't understand．Where did you want to go?

W: To work．Well, I only remembered it was Sunday when I arrived at the office and no one was there．I went back home and guess what? I didn't have my keys with me．There was no choice but to break one of the windows to get in．

M: Oh．It's funny．

(Text 10)

　　　 Movies are the favorite entertainment of many people．When a person becomes a movie star, everyone knows that person．Some movie stars are known for a few films and others for many films, Katherine Hepburn has made more than 50．films．Just being in a film does not make a person famous．It must be a good film and the part a major role．Katherine starred in the film On Golden Pond with Henry Fonda and his daughter Jane Fonda．In the film she was a retired mother and wife facing the problems of old age．It was a perfect performance．In many films Katherine's acting skills are so good that she becomes just like the person she is acting, and that's the reason why the audience like her so much even today．

第一节：改错: 请找出下列短文中的错误，并改正。

　　　 注意, 没有错误的不用改。(每小题0．5分共5分)

I was used to complain about my English teacher　　　　　　　　　　 1．___________

for his bad English．I was also tired with his teaching methods,　　　　　 2．___________

it were always slow and boring．However, my attitude towards　　　　　　 3．___________

him began to change after one afternoon．It was raining　　　　　　　　　 4．___________

heavy and I didn’t attend school．Around 5:30 pm I received　　　　　 　　5．___________

a phone call．“Are you all right?” asked my English teacher in quiet　　　　 6．___________

voice．On hearing her words, I was shocked and my mind was　　　　　　 7．___________

flooded with mixed feeling．He was showing his concern　　　　　　　 　8．___________

for me, though I have not been happy with him! Was he just　　　　　　　 9．___________

acting and should I smooth away my past misunderstanding of him?　　　　 10．___________