题干

如图所示,方盒A静止在光滑的水平面上,盒内有一个小滑块B,盒的质量是滑块质量的2倍,滑块与盒内水平面间的动摩擦因数为μ;若滑块以速度v开始向左运动,与盒的左右壁发生无机械能损失的碰撞,滑块在盒中来回运动多次,最终相对盒静止,则此时盒的速度大小为____;滑块相对盒运动的路程____。


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v3,v23

同类题4

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山水之歌

山

     我非悲天的仁者,但我爱山。我爱大山的巍峨、壮阔,也爱小山的险峻、耸峙;我爱那峰林的奇峭、砥柱的岑危、青城的神奇、剑门的天险和那半屏的如障、群峦的绵延;我爱那氤氲缥缈的晨山,也爱那风起云涌的暮山;我爱看那尺寸千里、缵簇萦纡、阴阳割昏晓的(A),也爱那云龙远岫、横岭侧峰或悠然见到的(B)。山在我生命中,是枕,是“梦回山枕隐花钿”;是砚,是“水笔山砚入案来”。不知是哪位朋友说:“你的话语,环绕着我,如同远远近近的小山。”我则要说:“远远近近的小山,环绕着我,如同喁喁的私语。”

     我爱山,以山为友,以山为灵,以山纳入我的画境,更终日向山,对语卿卿,如那“相看两不厌”的(C)。

水

     我非智者,但我爱水。

     我爱水的柔,柔如蓝色的秀发;我爱水的刚,刚如白色的奔马。我爱那石浅水潺潺的抒情,也爱那惊涛裂岸的壮阔;我爱那深山的冷冽、濯足的清流、浣纱的小溪,也爱那帆影的秋江、飞花的春水和惊涛的海洋。

     如果在夜晚,看明月松间、清泉石上,听苏子吟唱、渔歌互答、村妇砧杵,而浮光耀金、静影沉壁,将是何等地闲适。

     如果在黄昏,楼观沧海,石钓钱塘,看潮升汐涌、淘浪排空、孤樯危舟、乍隐乍现,而临海古朝的钟声依然,将佛陀的灵悟,送过山门,将是何其地悲壮。

     我也爱那烟冲九霄、水流千丈,把那江河拦腰截断,再顿时倾注下去的巨瀑,那是大地的震撼、川流的怒吼,使我置身其间,变得如此渺小。

     我更爱那穿云一线、悬岩坠落,范宽《豁山行旅图》中的窈远,那水如琴弦,在群峰的共鸣箱上,弹奏悠扬,清风飒飒、溪水潺潺、僧行踽踽、旅者匆匆,而半角红墙、一楼楹瓦,隔着千重树影,面对满目青山,该是多么地悠然。

     我爱水,愿以水裁衣,以云织绵,做一条弯弯的川流,在斜晖脉脉时,送千帆天际;愿以山切割,以石磋磨,做一涧高高低低的疾流,在猿啼虎啸中,将一叶轻舟,载过万重山。

同类题5

    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____ .