题干

某同学“测量滑轮组的机械效率”的实验装置如图所示。

实验时把更72N的物体吊在滑轮上,向上缓慢拉动弹簧测力计,测出物体上升高度和绳端移动距离分别为0.lm和0.3m。图小弹簧测力计示数为____N,滑轮组机械效率为____%.如果用此滑轮组提升另一重为10N的物体,它的机械效率____(填“变大”、“变小”或“不变”)。

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答案(点此获取答案解析)

3,80,变大

同类题4

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一滴眼泪换一滴水

(法)雨果①

    与本文有关的情节:克洛德副主教垂涎吉普赛姑娘爱斯梅拉达的美色,唆使养子伽西莫多拦路劫持爱斯梅拉达,伽西莫多被官兵抓住,判鞭刑。

群众有等候观赏公开行刑的习惯,他们用观看邢台来消磨时间。

当伽西莫多给拖到刑台顶上的时候,当人们能够从各方面看见他被人用绳子和皮条绑在刑台的轮盘上的时候,场内爆发了一阵笑声和喊声,人们认出他就是伽西莫多。

    人家叫他跪在那块圆形底座上,他照着做了。人家脱掉了他的上衣和衬衣,直到露出胸膛,他也听之任之。群众看见了伽西莫多赤裸的驼背,突起的胸脯,长着许多硬皮和汗毛的肩膀,便爆发出一阵哄笑。正当大家笑闹的时候,施笞刑的大头目比埃拉爬上了平台,到了犯人身边。

随着轮盘的转动,比埃拉抬起胳膊,皮鞭挥起,发出水蛇般的嘶嘶声,一鞭又一鞭疯狂地落到那可怜人的肩膀上。人们看见成千条血水在那驼子的黝黑的肩膀上流淌,皮鞭在空中挥动时把一些血珠也溅到了观众的身上。伽西莫多脸上的呆笨表情变成了痛苦和懊丧,他闭上独眼,把头垂到胸前,仿佛死去了似的。

    轮盘停止了转动,施刑人停止了鞭打,笞刑算是执行完了。可是对于伽西莫多,这还未完事,他还要在刑台上示众一个钟头。当“公诉”执行完毕,就轮到千万种私人的报复了。

    “邪教的怪物!”一个说。

    “骑扫帚把的家伙!”另一个嚷道。

    “做个凄惨的怪笑吧。”第三个说。

    成千种侮辱性的语句像雨点般落在他身上,场上处处都有人诅咒他,嘲笑他,向他叫骂,向他投石子。伽西莫多虽然耳聋,但他看得很清楚,群众的狂怒表现在脸上的并不比表现在话语里的少,向他投来的石子也能说明群众是在哄笑。他愤怒、憎恨、失望,脸上布满了厚厚的阴云。

    这时,他远远望见一个神甫骑着骡子经过,这可怜人的脸色就温和起来,一直控制着他的那种愤怒变成了奇特的充满了难以形容的甜蜜宽厚而温和的微笑。那神甫愈走近他,⑴他的笑容就愈加明显,愈加清晰,愈加光辉灿烂,简直像是不幸的人所崇敬的救主降临了似的。可是当那头骡子靠近了刑台,使骑在它背上的神甫看清了犯人是谁的时候,那神甫却低下眼睛,用两只踢马刺踢着骡子急忙转身走开了,好像在逃避一声耻辱的呼唤似的,他很不愿意在    那种场合被一个不幸的人认出来并且向他致敬呢。

    那个神甫正是副主教克洛德。⑵伽西莫多的脸色黯淡起来了。微笑还在一片阴云间停留了一会,但那是痛苦的、无力的、带着深深悲哀的微笑。

时间一点点过去,他在那儿至少待了一个半钟头,被人不停地折磨,虐待,嘲笑,投石子。突然,伽西莫多带着加倍的失望在锁链里挣扎,他打破缄默,用嘶哑愤怒的如动物般的声音吼叫:“给水喝!”这声悲惨的呼唤,并没有引起同情,反而使刑台四周的市民笑得更加厉害。

几分钟后,伽西莫多用失望的眼睛扫视了人们一遍,又用更加令人心碎的声音喊道:“给水喝!”仍然只引起一阵哄笑。

    “给水喝!”伽西莫多喘息着喊了第三遍。

    这时他看见人群里闪开一条路,走出了一位装束奇特的姑娘,身边带着一只金色犄角的雪白的小山羊,手里拿着一面小鼓。

伽西莫多的独眼闪了一下,原来就是他昨晚曾经想抢走的那个波希米亚姑娘呀。他模糊地意识到正是因为那件事他此刻才在这里受惩罚的呢。他十分相信她也是来向他报复的,也是像别人一样来打他的。看见她真的迅速走上了石级,愤怒和轻视使他透不过气。

只见爱斯梅拉达一言不发地走近那犯人,从胸前取出一只葫芦,温柔地举到那可怜人干裂的嘴边。这时,人们看见他那一直干燥如焚的独眼里,滚出了一大颗眼泪,沿着那长时间被失望弄皱了的难看的脸颊慢慢流下来。这也许是那不幸的人生平第一次流出的眼泪。

那漂亮、鲜艳、纯洁、迷人而又那么娇弱的姑娘,竟会那样好心肠地跑去救助一个如此可怜丑恶的家伙,那情景无论如何是很动人的,而这件事又发生在一个刑台上,那就更为动人了。

    ​观众也都被感动了,大家拍着手喊道:“好极了,好极了!”

                                      (节选《巴黎圣母院》,陈敬容译,有删改)

【注】①雨果(1802-1885),法国十九世纪伟大的浪漫主义文学家,法国文学史上最伟大的作家之一。

同类题5

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    Developed and developing nations can learn from each other seeking a low carbon economy, a Chinese government official said in Shanghai yesterday. “China doesn't lag developed nations in terms of energy saving and green economy”, said Zhou Changyi, director of the energy saving department of the Ministry of Industry and Information Technology.

    “While we can learn many aspects from developed nations, they also should learn something from us, such as water conservation,” Zhou said in a speech during the new Path of China's Industrialization forum at the ongoing China International Industry Fair 2009.

    He said industrialized nations and China are dealing with different issues to combat climate change. The United Kingdom, for example, is concerned about transport, buildings and new energy in reducing carbon emissions. For China, the most urgent task is how to realize new type of industrialization and avoid mistakes that other countries made when they industrialized.

    As such, overseas exhibitors at this year's fair are showing ways to help China achieve low carbon emissions in the industrial section.

    Swiss power and automation technology group ABB called for a stronger focus on product lifecycle assessment, or LCA, which is used to study the environmental impact of a product from the research and manufacturing stage through its usage and recycling.

    Tobias Becker, head of ABB's process automation division for North Asia and China, said LCA is an effective tool in helping manufacturing industries to reduce carbon emissions.

    LCA shows that industrial customers should focus on a product's environmental impact throughout its lifecycle instead of on its initial investment or ready to use stage. For example, a motor's initial investment accounts for only 3 percent of its lifecycle cost, while 94 percent goes to fuel consumption and the rest to maintenance.

    Richard Hausmann, North East Asia CEO of Siemens, said, “The color of future industrialization is green.”

    The Germany Company recently announces that it wants to receive orders worth more than 6 billion Euros (US 8.8 billion) for intelligent net power networks, Smart Grid, over the next five years. Siemens has set a 20 percent market share target for the global smart grid business.

    A smart grid delivers electricity from suppliers to consumers using digital technology, advanced sensors specialized computers that save energy, reduce costs and increase reliability. The United States and China are considered the two biggest markets for smart grid.