题干

如图1所示,甲为某一简谐波在t=1.0 s时刻的图象,乙为甲图中C点的振动图象,则下列说法正确的是    (   )

A:甲图中B点的运动方向向左

B:经过0.5s,质点C将运动到B点处

C:若该波与另一列简谐波发生了叠加,则另一列波的波长必须为4m

D:若该波与另一列波发生了稳定的干涉,则另一列波的频率必须为1 Hz

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D

同类题4

    Photography is about taking photographs. In 1826, a Frenchman named Niepce needed pictures for his business. But he was not a good artist. So he invented a very simple camera. He put it in a window of his house and took a picture of his garden. That was the first photograph.
The next important date in the history of photograph was 1837. That year, Daguerre, another Frenchman, took a picture of his studio. He used a new kind of camera and a different process. In his pictures, you could see everything very clearly, even the smallest details. This kind of photograph was called a daguerreotype.
    Soon, other people began to use Daguerre's process. Travelers brought back daguerreotypes from all around the world. People photographed famous buildings, cities and mountains.
    In about 1840, the process was improved. The photographers could take pictures of people and moving things. The process was not simple. The photographers had to carry lots of films and processing equipment(设备). But this did not stop the photographers, especially in the United States.
    Mathew Brady was a well-known American photographer. He took many pictures of famous people. The pictures were unusual because they were very life-like and full of personality. Brady was also the first person to take pictures of war. His 1862 Civil War pictures showed dead soldiers and destroyed cities. They made the war seem more real and more terrible.
    In the 1880s, new inventions began to change photograph. Photographers could buy films readymade in rolls(卷). So they did not have to make the film themselves. Also, they did not have to process(冲洗) the film at once. They could bring it back to their studios and develop it later. They did not have to carry lots of equipment. And finally, the invention of the small hand-held camera made photography less expensive.
Photography is also a form of art. Some photographs were not just copies of the real world. They showed ideas and feelings, like other art forms.
Title: The ____ of Photography

Photography doesn’t only mean taking photographs; it is also a form of art. Photographs showed not only the real world, but also the ideas and feelings.
In 1826A Frenchman named Niepce invented a very simple camera and the first photograph was ____ by him.
In 1837Another Frenchman Daguerre invented a kind of photograph called    daguerreotype. People could see____  things in the pictures.
In 1840The photographers could take pictures of people and moving things
with lots of films and processing equipment.
In 1862An American photographer Brady took many pictures of real and ____    things in the war. He was the first person to take war pictures.
In the 1880sThere were films readymade in rolls(卷). Photographers did not have to carry lots of equipment any more. The invention of the small  hand-held camera made photography____ .

同类题5

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在大数据中“精准”生活

       ①万物皆互联,无处不计算。因为互联网、手机、无线传感器的普及,实时监测、远程协作、SOHO工作、数据管理已成为平常之事,信息像水电一样通过网络供应汩汩传输,计算机上有形数据转化为无形的财富,深入并造福于现实生活。

       ②这标志着云计算与大数据时代的开启。智能管理、社交网站、物联网、IPv6,当新技术风驰电掣般地驶入生活,我们如同搭上高铁列车,还来不及看清楚窗外的风景,就已呼啸着越过下一个站台。大数据应用于健康管理,几乎表征了新媒体技术层面的全部特征:电子档案高度个性化;人工智能帮助我们细分信息;远程协同记录用户的行为模式;数据挖掘预测人们的未来需要。而智能终端与“可穿戴”计算设备的出现,更使得行为、位置、生理数据等细微变化成为可供记录和分析的精准对象。

       ③尽管大数据这个名词并不新鲜,但社会对于大数据价值的认识尚在深化。20世纪80年代,美国人首先提出了这个概念。雅虎的科学家发现,得益于计算 机技术和海量数据库的发展,个人在真实世界的活动能够得到前所未有的记录。随着新媒体技术的更新,如今,大数据的概念逐渐拓展,涵盖了从数字图象、新闻跟 帖、文本记录、视频文档、社交平台互动所提供的所有信息。不仅如此,它还被视作一种能力,引发了社会和国家战略层面的深刻关注。

       ④大数据之“大”,不仅在于容量,更在于社会对其价值的洞悉:在大数据所重塑的后信息环境中,一个大规模生产、分享和应用数据的世界扑面而来。正如学者维克托•迈尔﹣舍恩伯格所说,它的真实价值就像漂浮在海洋中的冰山,第一眼只能看到一角,绝大部分隐藏于表面之下

       ⑤但即便如此,我们依然可以清楚察觉到大数据给社会带来的一些改变。从谷歌的流行病分析系统到沈阳浑南居民的数据查询终端,基于信息的创新成为服务 的先导,连接民生,可以救助更广泛的普通大众;以云计算为基础的信息存储、分享和挖掘手段,推动着数据的交换、整合和分析,可以帮助人们发现新知,创造新 的价值;作为新发明和新服务的源泉,大数据也影响到传统学科研究的分化,改变了人们的价值取向、知识结构和生活方式。有学者将大数据比作观察人类自身社会 行为的显微镜和仪表盘。而我们看到,这个新的测量工具,再一次引领新的繁荣,提供给人们更多的选择。

       ⑥作为发掘价值、征服数据的强大引擎,大数据所带来的更多改变蓄势待发。站在创新、竞争和生产率提高的前沿,思索大数据对于生活的意义,如何将数 据、信息转化为知识,扩大人类的理性,实现技术与智能服务的跨越?如何规避风险、应对它对管理世界所提出的挑战?如何借助于大数据的力量将人类的观察和理 解推向“精准”,并衍生出有效的解决方案?答案还存在于人类智慧的彼此交融之中。

(选自《人民日报》2014年5月,有删改。)