试题与答案

如图,在光滑水平面上有一质量为m1的足够长的木板,其上叠放一质量为m2的木块.假

题型:选择题

题目:

如图,在光滑水平面上有一质量为m1的足够长的木板,其上叠放一质量为m2的木块.假定木块和木板之间的最大静摩擦力和滑动摩擦力相等.现给木块施加一随时间t增大的水平力F=kt(k是常数),木板和木块加速度的大小分别为a1和a2,下列反映a1和a2变化的图线中正确的是(  )

A.

B.

C.

D.

答案:

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参考答案:蘸煤油、酒精或丙酮的棉球;放入温水中,将其缓慢

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题型:阅读理解

阅读理解。

    There are many kinds of cars in this world. My grandfather thinks this is because cars are like their

drivers. He says, "Rich people have expensive cars, big people have large cars, and old people drive old

cars." But I don't agree with him. 

     My neighbor, Mrs. Hill, is 82 years old. She drives only on Tuesday, and then she drives only to the

bank. She never drives more than 30 kilometers an hour. Do you think Mrs. Hill has a very old and small

car? No! Her car is new. It's very large, and it can go 200 kilometers an hour!

     My friend Mike is an artist. He paints beautiful pictures with lots of colors. But his car is black.

Mrs. Bates has a very, very old car. It often has some trouble. Does she drive that kind of car because

she is poor? No, she has four restaurants and two million dollars in the bank. My uncle Joe has a very

small car. Every Sunday, he drives to the country with his wife, his three children, his mother and his dog.

    Now, you have read about my friends and their cars. Do you agree with my grandfather? Maybe you

have a car. Does it say something about you?

1. The writer's grandfather thinks ___. [ ]

A.a person has the same kind of car as himself (herself)

B.different people have cars of the same kind

C.poor people have large cars

D.artists have black cars

2. Mrs. Bates has an old car ___.[ ]

A.because she is poor

B.because she is rich

C.because she likes old cars

D.and the passage doesn't tell us why

3. Though Uncle Joe has a very small car, ___. [ ]

A.he has a dog

B.he has a large family

C.he has no children

D.he has few members in his family

4. The writer's friend Mike paints ___. [ ]

A.pictures in black

B.colorful pictures

C.colorless pictures

D.pictures with only a few colors

5. The writer thinks ___. [ ]

A.his grandfather's idea about cars is right

B.cars are often the same as their drivers in many ways

C.artists shouldn't drive black cars

D.a car doesn't say anything about its owner

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