题干

一均质正方体放入水中,静止时物体有 的体积浸入水中,物体的密度是____kg/m3;若把该物体放入密度为0.8×103kg/m3的酒精中后;则该物体下表面受到水的压强p与受到酒精的压强p的关系是p____p(选填“>”、“=”、“<”=)

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0.6×10 3,=

同类题1

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幺八

周同宾

    幺八幼时,曾拉盲艺人游乡卖唱。从山区唱到平原,唱遍村村寨寨。师父死了,埋殡罢,他不想再漂泊,就用剩下的钱买地,娶妻,在我们村落户了。

    他人极好,乡亲们从不把他视为外人。加上和福二爷拜了把子,年轻人就把他当作长辈看待,叔咧爷咧,叫得亲热。幺八爱唱,唱大调曲子。幺八会唱多少段,他自己也说不清。福二爷会弹三弦,经幺八教调,技艺大进。还有个瞎老五,孤身一人,和一架古筝厮守几十年。三人常搭档,闲来演唱,忘忧亦忘年。

    那时,尚在童年。一日,晚饭后,没人玩,好烦恼。奶奶说:“幺八爷唱曲儿呢,听去吧。”

    踏着月光,跑到幺八家。满院都是丝竹声,丝丝瓤瓤的,好似一进门就被缠绕着。堂屋里,一盏灯,一定点着三四根灯草,很亮。一张八仙桌,三把太师椅。瞎老五居中,桌上放古筝,十个手指在弦上起起落落。福二爷坐左边,怀抱三弦,头随着音乐前后俯仰。幺八在右,身腰直挺,二目微闭,手持檀板,击着节拍,缓缓地吟唱。大人小孩,坐了半屋,都屏息静听。我挤进人缝儿,正对他站着。怪不得人们管唱大调曲子叫哼曲子,他的声音就好像从鼻子里发出,却那么细,那么柔,又那么响,那么脆,拖出尾音,震荡得满屋子都瓮瓮共鸣。唱的啥,我听不懂,只觉得好听,耳里美,心里美,身上的每个毛孔都美。瞎老五的古筝好似被幺八的唱腔牵扯着,一会儿轻拢慢捻,十三根丝弦像凑在一起压低嗓子说悄悄话儿,一会儿嘈嘈切切,像三伏天的猛雨一般。有时,乐音戛然一停,又突地噔的一声,像一颗圆圆的石子落入老井。福二爷拨弹着,两眼眯眯的,嘴角带微笑,三弦似乎就是他心中发出的笑声。我呆呆地站着,忘掉了世界,满耳里只有幺八的哼唱,和在梦中也没听过的音乐。只觉得,似有一条清凌凌的小溪,溅着浪花儿,漾着波纹儿,潺潺地流进我的心田,那么滋润,那么熨帖;又觉得,似有一只手,带着温情,带着叮咛,带着慰藉,亲亲地轻抚我的面颊,我的心头,我感到怎也说不出的愉悦,兴奋……

    夜深了,月光照进了屋子。曲未终,人未散,奶奶硬把我拽回家。躺床上,满耳满心似仍是那动人的歌吟,动人的乐音。我做了梦,梦见蓝天白云,彩霞长虹,绿草红花,莺啼燕语,和一片片从未见过的风景……

    那是我这辈子第一次被音乐征服。想不到捉摸不住的声腔乐曲对一个儿童的心灵竟有如此大的冲击力。

    据说,幺八会唱的曲目共三百多个。其中一部分只他能唱,别无传人。他自己琢磨出的新唱法如《银扭丝》带《垛子》,《罗江怨》带《哭扬调》(皆为曲牌名),没人能学来。

    “文革”肇始,幺八被批被斗,人格受辱,斯文扫地。不久,郁郁地死去,他的一肚子曲词,他的独有的声腔,也随他埋进三尺黑土之下,永难再见天日。

    下葬后,福二爷在坟前大哭一场,别人去了,他仍不走,直坐到深夜。从此,再不弹三弦。死后七天,瞎老五抱着古筝,磕磕绊绊摸到坟前,奏一阕《高山流水》,而后,摔筝于地,用脚猛踹,弦断筝毁……

(选自《散文百家》2010年第一期《真不该忘了他们》,有删改)

同类题2

阅读理解

    Cycling or even walking in city areas can be a little dangerous, thanks to the fact that one is sharing the road with vehicles that are increasingly getting larger and heavier. A recent study proves that of the 1.27million people that die in road traffic crashes each year, about half are walkers, motorcyclists and cyclists. Now there may be a solution that could provide at least some help to protect this helpless group---an airbag!

    If you are worried that this safety measure will involve you taking around a heavy package or worse still, wrapping yourself inside an ugly plastic bag, the bag is fitted not on the human, but on the outside of the vehicle. And, while there are several versions of the idea in the works, the one most recently unveiled by Dutch car company TNO, seems to be the most advanced and ready to go into production.

    In the works since 2011, the airbag covers only the lower part of the windshield. This will provide the much needed buffer(缓冲)between the person's head and the pane of glass he/she would otherwise meet.

    The chain of events leading to an airbag cause are quite simple---A camera fitted beneath the rear-view mirror monitors the vehicle's closeness to a walker or cyclist. Any contact with either one of them sets off the sensors in the car's bumper and quickly blows up the airbag. In addition to that the sensors also set off the car's automatic brake, reducing the chances if an even worse injury.

    In tests conducted using a model, the success of not getting injured after being hit by a car travelling at about 40km/h was about 50-50! While not perfect, it will still result in reducing the number of deaths by a huge amount.

    With TNO ready to license its technology to car makers and many more companies trying to develop similar concepts, we would not be surprised if outer airbags become a standard feature in every car pretty soon.