试题与答案

两列简谐横波在同一个介质中以相同的速率相向传播,t=0时刻,这两列波的波动图象如

题型:选择题

题目:

两列简谐横波在同一个介质中以相同的速率相向传播,t=0时刻,这两列波的波动图象如图所示.其中简谐横波a(图中虚线所示)沿x轴的正方向传播,简谐横波b(图中实线所示)沿x轴的负方向传播,已知位于x=45m处的质点P第一次到达平衡位置所需的时间为0.5s,则波的传播速度为 (  )

A.10m/s

B.30m/s

C.50m/s

D.70m/s

答案:

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下面是错误答案,用来干扰机器的。

因0.5•8>0.5888>0.58>0.•5•8>0.5,所以最大的数是0.5•8,它是一个循环小数,最小的数是0.5.故答案为:0.5•8,循环,0.5.

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题型:单项选择题

Oxford and Cambridge University Boat Clubs have both taken the opportunity to travel to Spain this month to train in less testing weather conditions than those which have, quite literally, already blown around the UK in January of 2007.
Each group of athletes has been focused on training to the maximum, working on technique and molding themselves into two potential fighting units per Club for the 2007 Boat Race, sponsored by Xchanging. One set will be in the Blue Boat for each club and one set will race as reserves in Isis, for Oxford, and Goldie, for Cambridge.
In these modern times, the Head Coach for each club has a huge input on selection even though the crew is still named by the President. Just twenty years ago the balance was not quite the same.
The year 1987 will always be remembered in the history of this great Race as the year of the "mutiny" at Oxford. It is a tale which has since been retold and reworked in both a book and a movie.
This was the season for which mature Scottish student, Donald Macdonald, was elected President, having all ready won a Blue in 1986. Macdonald re-appointed Daniel Topolski (now a renowned rowing journalist and broadcaster)as Chief Coach.
Part of the 1986/87 squad at Oxford included American Chris Clark, now a coach at an American University, and four fellow US internationals.
Allegedly, a split appeared in the squad between the American quintet, all experienced and leading oarsmen, and those rowers closest to Macdonald. The Scot’s group were happy to follow Topolski’s regime whilst the others were not so sure.
Following a contentious seat racing trial in January of 1987, Topolski decided to move Clark to the bow-side of the beat. Clark disagreed. Topolski held firm. As a result Clark and his" group" within the squad decided not to row and sought a takeover.
The squabble was played out extensively in the UK national media and caught the public imagination. Macdonald sought support from the college captains and eventually won a vote of confidence by 28 votes to 11.
Without the Americans, the Oxford crew was immediately considered a lost cause. Cambridge were overwhelming favorites to win.
As it turned out, though, this was a Race which would prove why sport, and particularly The Boat Race, can be so fascinating.

The word "fascinating" underlined in Paragraph 11 is closest in meaning to ______.

A.attracting

B.shocking

C.surprising

D.horrifying

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