关于动量和冲量,下列说法正确的是: A做匀速圆周运动的物体,其动量不变 B汽车匀

题型:选择题

问题:

关于动量和冲量,下列说法正确的是:

A做匀速圆周运动的物体,其动量不变

B汽车匀速转弯,所受的合外力的冲量为零

C某同学站在地面不动,所受的重力冲量为零

D做匀变速直线运动的物体其动量均匀变化

考点:动量冲量
题型:选择题

任务型阅读。

     Henry was from the USA and he came to London for a holiday.

     One day he was not feeling well, so he went to the clerk(职员) at the desk of his hotel and said," I want to see a doctor. Can you give me the name of a good one?"

     The clerk looked up in a book and then said, "Dr Kenneth Grey. "

     Henry said, "Thank you very much. Is he expensive?"

    "Well," the clerk answered," You have to pay him two pounds for your first visit to him and 1. 50 pounds for later visits. "

     Henry decided to save(节省)0. 5 pound. So when he went to see the doctor, he said," I have come again, Doctor. "

     For a few seconds(秒) the doctor looked at his face carefully without saying anything. Then he said, "Oh, yes. " He looked him over and then said, "Everything goes as it should do. Just continue with the medicine I gave you last time. "

根据短文内容回答问题,每空一词。

1. Where did Henry come from?

  He ___________ from ___________.

2. What did Henry want to do when he didn't feel well?

  He wanted to ___________ a ___________.

3. How much did Henry have to pay the doctor for the first visit?

  He had to pay ___________ ___________.

4. Why did Henry say" I have come again"?

Because he wanted to ___________ ___________.

5. Did Henry get any advice from the doctor?

  __________ , he___________.

题型:选择题

锚锭大体积混凝土施工需要采取措施进行( )控制,防止混凝土开裂。

A.温度

B.湿度

C.强度

D.时间

题型:选择题

关系数据模型由关系数据结构、关系操作集合和 【2】 三大要素组成。

题型:选择题

手机银行转账汇款的历史转账记录可以保留()条。

A、7

B、15

C、5

D、10

题型:选择题

从运行方式上,汽轮机调节方式分为()和()。

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