问题 多选题

质量分别为m和M(其中M=2m)的两个小球P和Q,中间用轻质杆固定连接,在杆的中点O处有一个固定转轴,如图所示.现在把杆置于水平位置后自由释放,在Q球顺时针摆动到最低位置的过程中,下列有关能量的说法正确的是(  )

A.Q球的重力势能减少、动能增加,Q球和地球组成的系统机械能守恒

B.P球的重力势能、动能都增加,P球和地球组成的系统机械能不守恒

C.P球、Q球和地球组成的系统机械能守恒

D.P球、Q球和地球组成的系统机械能不守恒

答案

A、Q球的高度下降,重力势能减少,动能增加,由于轻杆对它做功,故Q球和地球组成的系统机械能不守恒.故A错误.

B、P球的高度上升,重力势能增大,动能增加,由于轻杆对它做功,故P球和地球组成的系统机械能不守恒.故B正确.

C、D对于P球、Q球和地球组成的系统,只有重力做功,系统机械能守恒.故C正确,D错误.

故选BC

完形填空

信息匹配(共5小题;每小题1分,满分5分)

请阅读下列应用文和相关信息,并按照要求匹配信息。请在答题卡上将对应题

号的相应选项字母涂黑 (若选择E,请涂AB;若选择F,请涂CD)。   

以下是各个电视节目的简介:

A. Wild World——this exciting show takes you around the world to places of unimaginable natural beauty and danger. Learn more about our world and see animals as they live in nature.

Time:Friday 8.30-9.30 pm

B. Sports Sunday—learn what’s happening in the world of sport. See how your team performed, find out who is playing and watch interviews with all your favourite sports stars.

Time:Sunday 1-5 pm

C. The Music Man——John Rogers is a musician by day but a secret superhero crime fighter by night in this long—running television action drama.

Time:Weekdays 3.00-4.00 pm

D. Lateline——All the latest news and opinions from around the world. If you want to know where there is trouble in the world or the reasons behind the global economic crisis,join our team of award winning journalists.

Time:Weekdays 9—10 pm

E. Entertainment This Week—Covers the world of entertainment. Hear this week’s number one song, watch the newest movie reviews and listen to all the latest gossip about the stars.

Time:Saturday 6 pm

F. Pop Star—Hundreds of young and (sometimes) talented performers sing the latest songs and compete to see who will become the nation’s newest Pop Star.

Time:Thursday 7.30 pm

以下是每个人的情况介绍,请匹配每个人与其拟选择的电视节目:

76. John Smith. John loves football and as a senior company manager needs to know the latest economic news. He seldom gets home before 10 o’clock at night during the week so he likes to relax in front of TV on the weekend.

77. Joan Johnson. Joan is a housewife who sometimes feels bored at home so she enjoys watching exciting TV shows. When the kids are home on the weekends and after school she never gets a chance to watch TV as they want to watch the shows they like.

78. Bill West. Bill is a music fan and a musician. He is always trying to hear the newest and most popular songs and learn more about his competitors. He is usually free after he finishes work at 5 pm except on weekends when he plays with his musical group in a local club.

79. Sarah O’connor. Sarah is trying to decide where she will spend her summer vacation. She has a number of different places in mind but is worried about terrorism and her safety so she doesn’t want to go anywhere that is dangerous or may become dangerous soon.

80. Robert Wise. Robert is a fan of action. He loves to watch exciting TV shows whether they are fictional or real. He usually only has time to watch TV on weekday evenings as he works during the day and on weekends he likes to go hiking and camping.

名词解释