问题 选择题

针对如图所示的情景,下列说法正确的是(  )

A.甲:从光滑的滑梯上滑下时,小孩的动能转化为势能

B.乙:对拉力器的作用力能使弹簧僻伸长,说明力能使物体发生形变

C.丙:往纸条上吹气,发现纸条会上升,是因为纸条受到的重力减小了

D.丁:在水平面上匀速推动箱子时,箱子受到的水平推力大予摩擦力

答案

A、从光滑的滑梯上滑下时,小孩的势能转化为动能.故A不正确.

B、乙:对拉力器的作用力能使弹簧僻伸长,说明力能使物体发生形变.故B正确.

C、往纸条上吹气,发现纸条会上升,是因为纸条上方空气流速大,压强小.故C不正确.

D、丁:在水平面上匀速推动箱子时,箱子受到的水平推力等于摩擦力.故D不正确.

故选B

阅读理解

When Ben Franklin was very only a boy, he always wanted to know about things. He was always asking his father and brothers “What?” and “How?” and “Why?”

They couldn’t always tell him what he wanted to know.

When they couldn’t tell him, Ben tried to find out for himself.

Many times Ben did find out things that no one knew before. The other boys would say, “That’s Ben Franklin! He’s always finding out something new! ” 

Ben lived close to the water. He liked to go there to see the boats. He saw how the wind blew them across the water.

One day Ben said to himself, “Why can’t the wind help me float across the water? And I’m going to try.” Ben got his big kite. He took hold of the kite string and ran with it. The wind took the kite up into the air. Then Ben jumped into the water.

The wind blew the kite high into the air. Ben began to float across the water. Soon he was on the other side, and he had not worked at all.

One boy shouted, “Look at Ben floating across the water! His kite takes him to the other side without any work!”

“Yes”, said another. “He’s always finding new ways to do things.”

小题1:When he was only a child, Ben _____.

A.liked to fly a kite by himself

B.always asked easy questions

C.always liked to play with water

D.always liked to find out how things worked小题2:His father and brothers _____.

A.couldn’t answer all his questions

B.could answer all his questions

C.tried hard to find out something new for him

D.were too busy to answer his questions小题3:How did Ben Franklin float across the water?

A.The other boy took him across it.

B.The water carried him across it.

C.The flying kite took him across it.

D.A boat took him across it.小题4:He found out many things that ____.

A.children didn’t know

B.his father and brothers knew

C.people didn’t know

D.most people knew

单项选择题