如图所示,质量M=0.6kg的平板小车静止在光滑水平面上.当t=0时,两个质量都

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问题:

如图所示,质量M=0.6kg的平板小车静止在光滑水平面上.当t=0时,两个质量都是m=0.2kg的小物体A和B(A和B均可视为质点),分别从左端和右端以水平速度v1=5.0m/s和v2=2.0m/s冲上小车,当它们相对于车停止滑动时,没有相碰.已知A、B与车面的动摩擦因数都是0.20,g取10m/s2.求:

(1)A、B在车上都停止滑动时车的速度;

(2)车的长度至少是多少?

(3)在图中所给的坐标系中画出0至4.0s内小车运动的速度--时间图象.

考点:功能关系动量守恒定律
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阅读短文,根据短文内容填上正确的单词  

    During his life Dr James Naismith worked as a doc-tor, taught P.E. and wrote several books. While he never thought it very important, Dr Naismith is today best known for one thing. He was the inventor of basketball.    

    Dr James Naismith was born in Canada in 1861 and his first job was at a special sports school in the USA.One day the school principal told James he was having a problem with the .students. Because of heavy snow, the students could not go outside. He told James that they needed a sport the boys could play indoors and gave the teacher two weeks to think of something.      

    It was on the very last day that James came up with  his idea. The" birth of basketball "is said to be on Decem- ber 21,1891,when two teams from the school played the first game. It was quite different from the basketball games of today. It had 9 players on each team and foot- balls were used instead of basketballs. Soon after, the game changed t0 5 players on each side, using special  " basketballs" through nets.     

   Although Dr Naismith did not live to see basketball become the worldwide game it is today, in 1936,just three years before his death, basketball became an Olym- pic sport. at the games in Berlin.  

1. Dr Naismith is ________ ________as the inventor of bas-ketball.

2. December 21,1891 was said co be the ________of bas-ketball.  

3. Today basketball has become the________ game.  

4. Dr Naismith died at the age of ________ .

5. Basketball became an________ sport at the games inBerlin in 1936.

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2008年9月19日至23日,省部级主要领导干部深入学习实践( )专题研讨班在中央党校举行。中 * * * * 、国家 * * 、中央军委 * * 胡 * * 在开班式上发表重要讲话。

A.科学发展观

B.十七大会议精神

C.社会主义荣辱观

D.可持续发展观

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男患32岁,在情绪激动后突然剧烈头痛,呕吐,4小时后来诊。神志不清,BP22.7/13.3kPa(170/100mmHg),肢体无瘫痪。颈强,克尼格征阳性,CT脑扫描可见右大脑外侧裂高密度影。

下列哪项检查可为病因诊断提供准确依据()

A.DSA

B.CTA

C.MRA

D.TCD

E.lumberpuncture

题型:问答题

二战后初期建立了以美国为中心的世界资本主义体系,被称为这个体系的三大支柱的组织不包括()

A.国际货币基金组织

B.国际复兴开发银行

C.关税与贸易总协定

D.世界贸易组织

题型:问答题

出租汽车驾驶员应自觉遵守法律法规和服务规范,牢固树立()的观念。

A.经济效益第一

B.安全运营,优质服务

C.安全运营与经济利益并重

D.效率至上,快速运送

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