如图所示,一只内壁光滑的半球形碗固定在小车上,小车放在光滑水平面上.在小车正前边

题型:选择题

问题:

如图所示,一只内壁光滑的半球形碗固定在小车上,小车放在光滑水平面上.在小车正前边的碗边A处无初速度释放一只质量为m的小球.则小球沿碗内壁下滑的过程中,下列说法正确的是(半球形碗的半径为R)(  )

A.小球、碗和车组成的系统机械能守恒

B.小球的最大速度度等于

2gR

C.小球、碗和车组成的系统动量守恒

D.小球不能运动到碗左侧的碗边B点

考点:机械能守恒定律动量守恒定律
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下列语句中,没有语病的一项是(   )(3分)

A.近期卫生部表示,将继续密切关注全国以及重点省份流感疫情的形势,加强对流感疫情的分析、研判和监测,对重点省份的流感防控工作予以指导。

B.《江南style》的走红,不仅仅是因为鸟叔的舞步契合了部分人慌张浮躁的心理特点,更主要的是由于对那种拜金主义及暴发的生活方式的反思而形成的。

C.在电影娱乐化倾向日益严重的情况下,对历史的追问,对生命的尊重,对人性的关怀,使《一九四二》成为极具社会责任感的作品。

D.美国总统奥巴马14日在白宫举行新闻发布会说,副总统拜登已向他提交了控枪对策建议,他本周将把这一控枪对策公诸于众。

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下列有关文学常识的表述不正确的一项是(   )

A.19世纪下半叶法国现实主义作家都德,在小说《最后一课》中成功地塑造了一个爱国知识分子形象——韩麦尔。

B.左拉是19世纪法国著名的自然主义作家,他的主要作品有《小酒店》《萌芽》《生之欢乐》等。

C.法国著名小说家莫泊桑,是世界短篇小说巨匠,《项链》是他的成名作。

D.曾获得诺贝尔文学奖的法国作家罗曼·罗兰,其成就最高的代表作是《约翰·克利斯朵夫》。

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1,2,3,0,5,-2,( )

A.3

B.7

C.5

D.9

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The elephant was lying heavily on its side, fast asleep. A few dogs started barking at it. The elephant woke up in a terrible anger: it chased the dogs into the village where they ran for safety. That didn’ t stop the elephant. It destroyed a dozen houses and injured several people. The villagers were scared and angry. Then someone suggested calling Parbati, the elephant princess.

Parbati Barua’s father was a hunter of tigers and an elephant tamer. He taught Parbati to ride an elephant before she could even walk. He also taught her the dangerous art of the elephant round-up—how to catch wild elephants.

Parbati hasn’ t always lived in the jungle. After a happy childhood hunting with her father, she was sent to boarding school in the city. But Parbati never got used to being there and many years later she went back to her old fife. "Life in the city is too dull. Catching elephants is an adventure and the excitement lasts for days after the chose," she says.

But Parbati doesn’ t catch elephants just for fun. "My work," she says, "is to rescue man from elephants, and to keep elephants safe from man. " And this is exactly what Parbati has been doing for many years. Increasingly, the Indian elephant is angry: for many years, illegal hunters have at- tacked it and its home in the jungle has been reduced to small pieces of land. It is now fighting back. Whenever wild elephants enter a tea garden or a village, Parbati is called to guide the animals back to the jungle before they can kill.

The work of an elephant tamer also involves love and devotion. A good elephant tamer will spend hours a day singing love songs to a newly captured elephant. "Eventually they grow to love their tamers and never forget them. They are also more loyal than humans. " She said, as she climbed up one of her elephants and sat on the giant, happy animal. An elephant princess indeed!

For Parbati, catching elephants is mainly to().

A. get long lasting excitement

B. keep both man and elephants safe

C. send them back to the jungle

D. make the angry elephants tame

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