题干

在一次实验中,小明把一根弹簧的上端固定、在其下端悬挂物体,下面是测得的弹簧的长度y与所挂物体质量x的一组对应值.


(1)上表反映了哪两个变量之间的关系?哪个是自变量?哪个是因变量?

(2)当所挂物体重量为3千克时,弹簧多长?不挂重物时呢?

(3)若所挂重物为7千克时(在允许范围内),你能说出此时的弹簧长度吗?

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答案(点此获取答案解析)

解:(1)上表反映了弹簧长度与所挂物体质量之间的关系;其中所挂物体质量是自变量,弹簧长度是因变量;

(2)当所挂物体重量为3千克时,弹簧长24厘米;当不挂重物时,弹簧长18厘米;

(3)根据上表可知所挂重物为7千克时(在允许范围内)时的弹簧长度=18+2×7=32厘米.

同类题1

根据短文理解,选择正确答案。

    Some people love going to museums,while others absolutely hate it and would rather stay at home,enjoying their favorite TV shows.Increasingly,museums are being seen as outdated and boring by today's youngsters.I have just returned to the UK after travelling around the USA. While there,I visited lots of museums  I must say,museums are typically educational, either to develop knowledge gained at school in particular subjects,or to enhance knowledge of other cultures

    In Chicago,we visited the world-famous Art Institute of Chicago.It was filled with paintings,drawings and sculptures by a huge variety of artists,such as Picasso,Monet,Matisse and Dali.

    There was a mixture of traditional and modern art,including colorful stained glass windows and abstract art.

    When we were in Washington D. C. ,we visited a few of the Smithsonian museums.These are all free to visit-which is great if you just want to see a few things,and not spend all day inside.

    The Air and Space Museum was particularly good:it had lots of aircrafts and rockets on display,interesting information and also some interactive parts.We also went to the National U.S.Holocaust(纳粹大屠杀)Memorial Museum.Naturally,it was sad to read about the horrors of this tragedy which affected so many people in World War II.However,it was also incredibly interesting to read the stories of those who survived the Holocaust,as well as those who helped others.

    Last but not least,I also found the 9/11 Memorial and Museum to be of great interest.This museum is dedicated to those who lost their lives,as well as their families,when the Twin Towers in New York City were attacked by terrorists in 2001It tells you how the terrorists planned the attack,how they hijacked the planes,and ultimately what happened as a result of their actions.Surviving pieces of the towers are shown in the museum,alongside damaged fire engines.It was a truly thought-provoking visit,which made me value my own life that little bit more.

    I think museums play an important role in preserving artifacts of historical importance for future generations.Whatever your interests,there is likely to be a museum for you.You can visit waxwork museums to see models of your favorite celebrities(and get photos with the Queen!),science museums for a more hands-on,interactive visit and so much more!Best of all,if you're ever in the UK,many of them are free!

同类题5

阅读下面的文字,完成小题。

害怕回乡

       ①回乡不是回家。

       ②回家是亲切的。记得母亲在世时,回家是那样温馨,是那样顺理成章。一踏上故土远远望见屋顶上的炊烟,望见炊烟下的竹篱后,有慈母倚门而望。

       ③未进门,早有乡邻,用真诚而纯朴的目光迎候你:“哇,回家来看母亲了。”

       ④匆匆推开柴门,扑进母亲怀里,一卸世路风尘的艰辛。

       ⑤母亲去世后,家就变得缥缈了。但那是我的根,那里有陶冶过我的乡情乡音。在那里,我懂得蒲公英是怎么飞的,蚱蜢是怎么跳的,画眉鸟是怎么唱的,它们都在呼唤我回归。

       ⑥回归是必然的,只是先人已渺,旧居不存,算不了回家,就算回乡吧。但回乡的路是艰难的。

       ⑦当我踏上那弯曲的乡路时,山还是那座山,村还是那个村。乡邻依旧友好,迎候你的目光,也依旧真挚。但话语里有了陌生:“啊,回来看看?”

       ⑧是的,回来看看,看什么呢?流水依旧白,青山依旧青。但自己的目光已不知往哪看,脚步不知往哪儿挪了。

       ⑨“到乡翻似烂柯人”,一颗系念故乡的心,顿时被悬起来了。因为随着母亲的去世,没有了依恋的那扇柴门,也没有了那一缕炊烟。

       ⑩于是无可挽回地坠入了从前,黯然地走进童年的记忆,很悲壮地站到昨日已远、来日无多的路口,踟蹰复踟蹰。在乡邻目光的探询下,不得不对自己的人生之路、回乡之路进行一番审视和梳理了。

       ⑪故乡,是生命的根,在抚摩生命之树的根须时,如果没有结出丰厚的果实来回报,那么你可曾以自己树冠的绿荫,给故乡送来一丝一缕的清凉?你会想到自己没有做官,不是荣归故里,你不很富有,不是衣锦还乡。你也不是明星,不为故乡增色。也许,这并不重要,故乡无意苛求于你。只是你对脚下的这片生你养你的土地,可曾作过应有的付出?

       ⑫想到此,你会明白前人为什么会有“近乡情更怯”的感喟了。

       ⑬你会感喟自己是一只小鸟,在山外的天空里飞了一圈;感喟自己是一条鱼,在人生的江河里漫游了一圈,如今日暮乡关,想到故乡厚实的土地,能歇你坎坷乡愁的奔波,能抚慰你疲惫至极的心灵。于是你回乡,因为你是从这里赤条条地来到世上,也是从这里背起行囊,携着故乡的期待,开始世路风尘的跋涉。而今倦游知还,鸟归林,鱼归渊,回到了生命的源头,你不得不回望一下自己的漫漫长途,也不得不反躬自问:你留在山外世界的行踪足迹是否歪斜?你是否行所当行,止所当止?你坐食的一饭一粥,是否取之有理有节?而对依旧贫瘠的土地,你是否无愧于心,无愧于乡呢?

       ⑭所以回乡,不止是回到往昔,回到记忆,而是回到生活的始发站,去审读自己的生命行程。

       ⑮回家,也许你会生出丝丝愧疚,但会因亲情的抚慰而释然。

       ⑯回乡,面对养育你的土地,你想到故乡的厚恩,未有寸功回报,你会怵然而惊。

       ⑰所以,我害怕回乡。