问题 选择题

如图所示,甲图为一沿x轴正向传播的简谐波在t=0时刻的波形图,a、b、c、d是这列波上的四个质点.则乙图是哪个质点的振动图象?(  )

A.a

B.b

C.c

D.d

答案

由振动图象读出质点在t=0时刻质点位于平衡位置且沿y轴正方向运动.

A、在t=0时刻a点位于波峰,与振动图象不符.故A错误.

B、简谐波沿x轴正向传播,则判断出来b点沿y轴正方向运动,而且位于平衡位置,与振动图象相符.故B正确.

C、在t=0时刻图中c点位于波谷,与振动图象不符.故C错误.

D、简谐波沿x轴正向传播,则判断出来b点沿y轴负方向运动,与振动图象不符.故D错误.

故选B

阅读理解

New York’s streets were covered by people dressed in elephant costumes (服装) and others waving antiwar posters with pictures of US President George W. Bush on them last week. But this was no carnival (狂欢节) – it was the Republican Party’s National Convention (共和党全国大会), which attracted thousands of protestors (抗议者). It was the largest protest ever at a US political convention, with at least 120,000 people marching through Manhattan on August 29. They demanded that the US leave Iraq and a new president be chosen.

The Republicans say the opposition – Democrat Party (民主党) encouraged the people on to the streets. They believe it is a democratic move to help win presidential election, to be held on November 2. The election is described as “the decisive battle between donkey and elephant”. The two animals are the symbols of the two major political parties in the US. The elephant represents (象征) the Republicans, whose candidate (侯选人), President George W. Bush, is trying to defeat the donkey to win his second them. The donkey represents the democrats, whose candidate, John Kerry, is trying to kick the elephant out of the White House.

Republicans think the elephant is powerful and clever, but the Democrats argue it is stupid and conservative (守旧的). In return, the Republicans regard the donkey as stubborn (倔强的) and silly but the Democrats say it is humble, plain, smart and courageous.

The Republicans have been sending emails to Bush supporters and journalists with the heading, “An Elephant Never Forgets”, said party spokeswoman Heather Layman. Elephants are known for their long memories. The emails suggest that Bush will keep his promises, while Kerry will not stick to his words.

It is interesting that both symbols were created by a single person, Thomas Nast, a famous political cartoonist of the late 19th century. During the election in 1874, Nast drew a cartoon, in which a donkey in a lion’s skin frightened an elephant marked “Republican”.

小题1:What does “kick the elephant out of the White House” mean?

A.Drive the animal out of the White House.

B.Drive President Bush out of power.

C.Keep the elephant out of the White House.

D.Insist on Bush’s being elected.小题2:In the eyes of the Republicans, the donkey is considered as      .

A.clever

B.foolish

C.polite

D.brave小题3: Which of the following is NOT true?

A.The same artist created the two symbols.

B.The emails suggest Kerry will not carry out his promises.

C.“An Elephant Never Forgets” means that an elephant has a good memory.

D.John Kerry is a Democrat.

单项选择题