问题 单项选择题

用如图所示的方法可以研究不同人的反应时间,设直尺从静止开始自由下落到直尺被受测者抓住,直尺下落的竖直距离为h,受测者的反应时间为t,则下列关于t和h的关系正确的是()

A.t∝h

B.t∝

C.t∝

D.t∝h2

答案

参考答案:A

解析:

直尺做自由落体运动,由位移公式可以求得t和h的关系.由自由落体运动的位移,可得,所以C正确。

故选C。

单项选择题
阅读理解

阅读理解。

     Parents and kids today dress alike, listen to the same music, and are friends. Is this a good thing?

Sometimes, when Mr. Ballmer and his 16-year-old daughter, Elizabeth, listen to rock music together and talk

about interests both enjoy, such as pop culture, he remembers his more distant relationship with his parents

when he was a teenager.

     "I would never have said to my mom, 'Hey, the new Weezer album is really great. How do you like it?'"

says Ballmer." There was just a complete gap in taste."

     Music was not the only gulf. From clothing and hairstyles to activities and expectations, earlier generations

of parents and children often appeared to move in separate orbits.

     Today, the generation gap has not disappeared, but it is getting narrow in many families. Conversations on

subjects such as sex and drugs would not have taken place a generation ago. Now they are comfortable and

common. And parent-child activities, from shopping to sports, involve a feeling of trust and friendship that can

continue into adulthood.

     No wonder greeting cards today carry the message, "To my mother, my best friend."

     But family experts warn that the new equality can also result in less respect for parents.

     "There's still a lot of strictness and authority on the part of parents out there, but there is a change

happening," says Kerrie, a psychology professor at Lebanon Valley College. "In the middle of that change, there

is a lot of confusion among parents."

     Family researchers offer a variety of reasons for these evolving roles and attitudes. They see the 1960s as

a turning point. Great cultural changes led to more open communication and a more democratic process that

encourages everyone to have a say.

     "My parents were on the 'before' side of that change, but today's parents, the 40-year-olds, were on the 'after' side," explains Mr. Ballmer. "It's not something easily accomplished by parents these days, because life

is more difficult to understand or deal with, but sharing interests does make it more fun to be a parent now."

1. The underlined word "gulf" in Para.3 most probably means _____.

A. interest

B. distance

C. difference

D. separation

2. Which of the following shows that the generation gap is disappearing?

A. Parents help their children develop interests in more activities.

B. Parents put more trust in their children's abilities.

C. Parents and children talk more about sex and drugs.

D. Parents share more interests with their children.

3. The change in today's parent-child relationship is _____.

A. more confusion among parents

B. new equality between parents and children

C. less respect for parents from children

D. more strictness and authority on the part of parents

4. By saying "today's parents, the 40-year-olds, were on the 'after' side", the author means that today's

    parents _____.

A. follow the trend of the change

B. can set a limit to the change

C. fail to take the change seriously

D. have little difficulty adjusting to change

5. The purpose of the passage is to _____.

A. describe the difficulties today's parents have met with

B. discuss the development of the parent-child relationship

C. suggested the ways to handle the parent-child relationship

D. compare today's parent-child relationship with that in the past