问题 选择题

两个物体P、Q的加速度ap>aq.则(  )

A.P的速度一定比Q的速度大

B.P的速度变化量一定比Q的速度变化量大

C.P的速度变化一定比Q的速度变化快

D.P受的合外力一定比Q受的合外力大

答案

A、加速度是表示速度变化快慢的物理量,与速度大小无关,故A错误;

B、加速度是表示速度变化快慢的物理量,在数值上等于单位时间内速度的变化量,不同时间速度改变量不同,故B错误;

C、加速度是表示速度变化快慢的物理量,P的加速度大,故P的速度变化一定比Q的速度变化快,故C正确;

D、由于质量大小未知,故无法比较合力大小,故D错误;

故选C.

阅读理解

One school night this month I walked quietly up to Alexander, my 15-year-old son, and touched his cheek gently in a manner I hoped would seem casual.A year ago he would have ignored this disturbance but now he reacted impatiently and leaned back to his computer screen.

I made a mistake: breaking into my teenager's personal space. “The average teenager has pretty strong feelings about his privacy," Lara Fox and her friend Hilary Frankel told me. Mr.Frankel and Mr.Fox, both 17, are the authors of Breaking the Code, a new book that seeks to bridge the generational divide between parents and adolescents.It is being promoted by its publisher as the first self-help guide by teenagers for their parents, a kind of "Kids Are From Mars, Parents Are From Venus" that explains the language and actions of teenagers.The girls dealt with issues including hanging out late, money, school pressures, smoking etc.

Personally, I welcome their opinions.The most common missteps in interacting with teenagers arise from the war between parents exercising their rights to know what goes on under their roof and teenagers firmly guarding their privacy.Teenagers can be quick to interpret their parents' remarks and respond with anger that masks their vulnerability (脆弱). Ms Fox said, "What we want above all is your approval.Don't forget, no matter how much we act as if we don't care what you say, we believe the things you say about us."

Nancy, a New York child-raising expert said she didn't agree with everything the authors suggested but found their arguments reasonable."When your kids are saying, ' You don't get it, and you never will, ' there are lots of ways to respond so that they will listen and that is what the writers point out."

" My parents helped me see that, " Mr.Fox told me, " even though they used to stay out late and ride their bicycles to school, times have changed and the way parents educate children is different.These days there is a major fear factor in bringing up kids.Parents worry about their child crossing the street." The writers said they hoped simply to throw light on teenage thinking.

小题1:According to the two girls, teenagers nowadays are ____.

A.independent

B.intelligent

C.inconsiderate

D.sensitive小题2:The underlined sentence "You don't get it, and you never will" in the 4th paragraph implies that ____.

A.the teenagers don't want/to admit their weakness

B.the teenagers think that their parents will never understand them

C.the parents do not necessarily force into the world of their children

D.the generation gap cannot be shortened despite their parents' efforts小题3:It can be inferred from the last two paragraphs that ____.

A.teenagers should guard their privacy

B.Nancy totally agrees with the two girls' opinions

C.parents are more concerned about children's safety

D.the two girls have obtained numerous support from the public小题4:Why does the author mention the book "Kids Are From Mars, Parents Are From Venus ?

A.It is one of the best-sellers

B.It is also written by the two girls

C.The two books have the similar theme

D.The two books have different opinions

填空题