问题 多选题

如图所示,物体A在水平推力F作用下沿水平面作匀速直线运动,不计空气阻力.下列说法中正确的是(  )

A.物体A受到的水平推力F与它受到的摩擦力大小相等

B.物体A受到的重力小于它受到的支持力

C.物体A对地面的压力大小与它受到的重力大小相等

D.物体A受到的水平推力F大于它受到的重力

答案

A、物体沿水平面进行匀速直线运动,物体在水平方向上受到的推力F,和受到的滑动摩擦力f是一对平衡力,大小相等.符合题意.

B、物体沿水平面进行匀速直线运动,物体在竖直方向上的重力和支持力是一对平衡力,大小相等.不符合题意.

C、物体沿水平面进行匀速直线运动,物体对地面的压力大小等于物体受到重力的大小.符合题意.

D、物体受到竖直向下的重力和推力没有关系.不符合题意.

故选A、C.

阅读理解

Once an Englishman named Larry Belmont went to Russia for a holiday. After he got back some of his friends came. “I had a very dangerous trip while I was in Russia.” Larry said, “I went to see a friend in the country and when the sun went down, I was still traveling through a forest in a sleigh(雪橇). It was a long way from my friend’s house when about twenty wolves began to follow my sleigh.”

“It was very dark in the forest. There was thick snow on the ground. First I heard the wolves. The noise was terrible! Then I saw long, grey forms among the trees, and soon the wolves were near me. They were running very fast, and they didn’t seem to get tired like the horses.”

“What did you do?” one of Larry’s friends asked.

“When the wolves got very near,” Larry answered, “I put up my gun and shot the first wolf dead. Then all the other wolves stopped and ate it, so my sleigh got away from them for a few minutes. Then they finished their meal, and I heard them coming again. The moon was shining brightly on the snow now, and after a few minutes I saw them running among the trees once more. They came nearer again, and then I shot another one of them, and the others stopped once more to eat it. The same thing happened again, and my horses become more and more tired and ran slower and slower until, after two hours, only one wolf was still alive and following me.”

“Wasn’t it too fat to run?” one of Larry’s friends asked.

小题1:The purpose of this passage is to ______.

A.amuse readers

B.tell an exciting adventure

C.praise Larry Belmont’s bravery

D.show the danger of traveling through a forest小题2:According to what Larry said, the last wolf _______.

A.was the strongest of all

B.had eaten up all the other wolves

C.ran much faster than the other wolves

D.was very fat and couldn’t run fast enough小题3:From what Larry’s friend asked at the end, we know that_______.

A.Larry’s trip was really dangerous

B.the last wolf was too fat to run

C.all the wolves had been shot by Larry

D.the friend did not believe what Larry had said