问题 填空题

测得某同学的质量为40Kg,当他立正时,他对地面的压力为______N,他走路时对地面的压强将是他站立时对地面的压强的______倍.

答案

当人站在水平地面上时,对地面的压力等于他的重力,所以G=mg=40Kg×10N/Kg=400N;

当走路时接触地面的面积是站立时的一半,由压强公式P=

F
S
可知,在压力不变时,受力面积减小,压强增大,所以压强将变为原来的2倍;

故答案为:400,2.

阅读理解

B

I always felt sorry for the people in wheelchairs. Some people, old and weak, can not get around by themselves. Others seem perfectly healthy, dressed in business suits. But whenever I saw someone in a wheelchair, I only saw a disability, not a person.

Then I fainted (晕倒) at Euro Disney due to low blood pressure. This was the first time I had ever fainted, and my parents said that I must rest for a while after First Aid, I agreed to take it easy but, as I stepped towards the door, I saw my dad pushing a wheelchair in my direction. Feeling color burn my cheeks, I asked him to wheel that thing right back to where he found it.

I could not believe this was happening to me. Wheelchairs were fine for other people but not for me, as my father wheeled me out into the main street, people immediately began to treat me differently.

Little kids ran in front of me, forcing my father to stop the wheelchair suddenly. Bitterness set in as I was thrown back and, forth. "Stupid kids… they have perfectly good legs. Why can't they watch where they are going?" I thought. People stared down at me, with pity in their eyes. Then they would look away, maybe because they thought the sooner they forgot me the better.

"I'm just like you!" I wanted to scream. "The only difference is you've got legs. and I have wheels. "

People in wheelchairs are  not stupid. They see every look and hear each word. Looking out at the faces, I finally understood; I was once just like them. I treated people in wheelchairs exactly the way they did not want to be treated. I realized it is some of us with two healthy legs who are truly disabled.

61. The author once______when she was healthy.

A. showed respect to disabled people

B. looked down upon disabled people

C. imagined herself sitting in a wheelchair

D. saw some healthy people moving around in wheelchair

62. Facing the wheelchair for the first time, the author        .

A. felt curious about it

B. got ready to move around in it right away

C. refused to accept it right away

D. thought it was ready for her father

63.The experience of the author tells us that "______".

A. life is the best teacher

B. people often eat their bitter fruit

C. life is so changeable that nobody can foretell

D. one never does to others what he would not like others do to him

64.Which is the best title for this passage?

A. How to Get Used to Wheelchairs

B. Wheelchairs Are as Good as Two Legs

C. People with Two Legs Are Truly Health

D. The Difference between Healthy People and the Disabled

65.How did the author feel when the little kids forced her father to stop the wheelchair suddenly?

A. Stupid.       B. Calm.     C. Excited.       D. Bitter.

单项选择题