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在函数y＝中，自变量x的取值范围是 ．
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函数y＝中自变量x的取值范围是__
已知函数y=mx+2x－2要使函数值y随自变量x的增大而增大则m取值范围是____________.
一次函数y=kx+b的自变量的取值范围是－3≤x≤6相应函数值的取值范围是－5≤y≤－2则这个函数的
函数y=中自变量x的取值范围是
图中折线是某个函数的图象根据图象解答下列问题.1写出自变量x的取值范围____________函数值
函数y=﹣2x2+4x中自变量x的取值范围是.
函数y=中自变量x的取值范围是
在函数y＝中自变量x的取值范围是_______.
若一次函数y＝kx＋b的自变量x的取值范围是－2≤x≤6相应函数值y的范围是－11≤y≤9则函数解析
－次函数y＝ax＋b的自变量x的取值范围为－2≤x≤6相应的函数值y的取值范围为－11≤y≤9则此函
函数y=中自变量x的取值范围是函数y=中自变量x的取值范围是
函数y=中自变量x的取值范围是
函数y=中自变量x的取值范围是x＞3.
函数y=自变量x的取值范围是______
函数中自变量x的取值范围是________函数y＝中自变量x的取值范围是____________
函数y=中自变量x的取值范围是______________
函数y＝中自变量x的取值范围是.
函数y=中自变量x的取值范围是___________.
函数y＝中自变量x的取值范围是__________.
函数y＝中自变量x的取值范围是___________.
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电加热眼罩对缓解眼疲劳有一定效果如图甲是一款市场上的产品小敏查阅使用说明书其相关参数如下 表乙． 乙 1当该款眼罩还剩10%的电池容量时在额定电压下充电充满电至少需要多少时间 2图丙是小敏设计的可以手动调节高中低三档加热的电热眼罩原理图．电源电压U恒为4.8伏已 知电热丝R1阻值为4欧电热丝R2阻值为6欧开关S3只接a或b． ①丙图电路中S1闭合S2断开S3接a时加热电路为选填“高”“中”或“低”温档． ②中温档功率为多少瓦 ③高温档工作20分钟眼罩消耗的电能为多少焦
科学研究中当设计多个因素影响的研究方案时每一次只改变其中的某一个因素而其余几个因素不变从而研究被改变的这个因素对事物的影响．以下实验中没有用到此方法的是
同学们学习了光的折射后知道了光从空气斜射入玻璃中时折射角小于入射角入射角增大折射角也增大．那么当光从空气斜射入玻璃中时折射角与入射角大小是否成正比呢【建立猜想】折射角与入射角大小可能成正比．【实验探究】同学们测得了四组实验数据．第2次实验如图所示请将实验数据填入表格中．【实验结论】折射角与入射角大小2选填成正比或不成正比．【评价与交流】根据实验数据还可以得出的结论是3．
Postingaphotoofthefoodyou'reabouttoeatonWeChathasbecomeadailyritual惯例;仪式formany.Oftenthisfoodinthephotoisn'tasappealingtothoselookingatitbutscientistsarenowclaimingtakingaphotoofyourfoodbeforeyoueatitmakesittastebetter. ResearchersatUniversityofMinnesota'sCarlsonSchoolofManagementclaimtakingaphotoputsyouinthemomentandindoingsoheightensyour41.Thepersontakingthephotowillonsomelevelfeelthemotivationtocontinuethepractice. Researcherswonderedaboutthepowerofritualsafternoticingthefunny42thatpeopleoftenperformbeforeeatinganddrinking.Theyconductedexperimentstoinvestigatewhetherthesekindsofhabitualbehaviourinfluencestaste. Inthefirstexperimentsomeparticipantswereaskedtoeatapieceofchocolatefollowingadetailedsetof43:‘Withoutunwrappingthechocolatebarbreakitinhalf.Unwraphalfofthebarandeatit.Thenunwraptheotherhalfandeatit.'Theotherparticipantswere44instructedtorelaxforashortamountoftimeandtheneatthechocolatebarhowevertheywanted. Theresultsshowedthatthosewhohadperformedtheritualratedthechocolatemore45enjoyeditmoreandwerewillingtopaymoreforthechocolatethantheothergroup. Asecondexperiment46thesefindingsshowingthat47movementsdon'tproduceamoreenjoyableeatingexperience.Thedataalso48thatalongerdelaybetweenritualandconsumptionenhancedtheseeffectsevenwithacommonfoodlikecarrots. Whiletheseritualsmayseeminsignificanttheresearchersnotethattheeffectstheyproducearequiteamazing.Andwhileritualsare49beforemealtimestheycouldplayaroleinother50too.
假定英语课上老师要求同桌之间交换修改作文请你修改你同桌写的以下作文.文中共有10处语言错误每句中最多有两处.每处错误仅涉最一个单词的增加删除或修改.增加:把缺词处加一个漏字符号∧并在其下面写出该加的词.删除:把多余的词用斜线\划掉.修改:在错的词下划一横线并在该词下面写出修改后的词.注意:1.每处错误及其修改均仅限一词;2.只允许修改10处多者从第11处起不计分.Inourlifeweoftenregretwhatwedidandwhichwecouldn'tdo.Actuallyitdoesn'tbenefitusatall.Asformostofuswemissedmanychancetoearnmoremoneytogetahighpositionandtorealizeourdreams.Weoftenregretthatwedon'tseizethoseopportunitiesthusfeelupset.AlthoughwedoknowregrettingthePastisnobenefitbutwestillcan'thelpdoingitToavoidtheproblembelowweneedtopaymoreattentiontowhatyouaredoingnowmakingusbusierandhavingnotimetorecallthepast.Moreoverwe'dbettersetreasonablygoalsonebyone.Onlybydoingsocanwestruggleforourfuturebetter.
正因为是他被任命为经理该公司在过去的十年中迅速发展为广告业巨头.It.
ThereweresomanynightswhenIasayoungboyhadtowatchhelplesslyasmyfatherverballyandphysicallyabusedmymother.Icanstillrecallthesmellofalcoholseethefearinmymother'seyesandfeelthehopelessmiserythatcomeswhenweseepeoplewelovehurtingeachotherinincomprehensibleways. Iwouldnotwishthatexperienceonanyoneespeciallynotachild.IfIsettledowninthosememoriesIcanfeelmyselfwantingtohurtmyfatherbackinthesamewayshehurtsmymotherandinwaysofwhichIwasincapableasasmallboy.Iseemymother'sfaceandIseethisgentlehumanbeingwhomIlovedsoverymuchandwhodidnothingtodeservethepainimposeduponher. WhenIrecallthisstoryIrealizehowdifficulttheprocessofforgivingtrulyis.IntellectuallyIknowmyfathercausedpainbecausehewasinpain.SpirituallyIknowmyfaithtellsmemyfatherdeservestobeforgivenasGodforgiveusall.Butitisstilldifficult.Thesufferingswehavewitnessedorexperiencedliveoninourmemories.Evenyearslatertheycancauseusfreshpaineachtimewerecallthem. AreyouhurtandsufferingIstheinjuryneworisitanoldunhealedwoundKnowthatwhatwasdonetoyouwaswrongunfairandundeserved.Youarerighttobeoutraged.Anditisperfectlynormaltowanttohurtbackwhenyouhavebeenhurt.Buthurtingbackrarelysatisfies.Wethinkitwillbutitdoesn't.IfIslapyouafteryouslapmeitdoesnotlessenthestingIfeelonmyownfacenordoesitweakenmysadnessastothefactyouhavestruckme.Revengegivesatbestonlymomentaryrelieffromouremotionalpain.Theonlywaytoexperiencehealingandpeaceistoforgive.Untilwecanforgiveweremainlockedinourpainandlockedoutofthepossibilityofexperiencinghealingandfreedom;lockedoutofthepossibilityofbeingatpeace. Withoutforgivenessweremaintiedtothepersonwhoharmedus.Weareboundwithchainsofbitternesstrapped.Untilwecanforgivethepersonwhoharmedusthatpersonwillholdthekeystoourhappiness;thatpersonwillbeourjailer监狱看守. Whenweforgivewetakebackcontrolofourownfateandourfeelings.Webecomeourownliberators.Forgivenessinotherwordsisthebestformofself﹣interest.Thisistruebothspirituallyandscientifically.Wedon'tforgivetohelptheotherperson.Wedon'tforgiveforothers.Weforgiveforourselves. 66.Whydidthewritermentionthestoryofhisfather'sabuseofhismom A.Becausehelovedhismomandwantedtofightbacksomeday. B.Becausehisfatherfinallyrealizedhisownmistakeandwasforgiven. C.Becausewitnessinghismom'ssufferingisstillhurtinghimandhasnowaytorelieve. D.Becausehefeltthathewasspirituallyrelievedfromthepainthroughforgiveness. 67.Thewriterwrotethearticleinordertotellpeoplethat. A.wemayneverhealourpainsorsufferingsintheheartunlesswelearntoforgive B.weshouldneverforgetthesufferingsburiedinourhearts C.wemaygettiedtothepersonwhoharmedusallthroughlife D.weshouldn'tworryaboutthepainswecausedsinceforgivingisalwayseasierthanimagined 68.Whatisthe4thparagraphmainlyabout A.Hurtingbackdoesnogoodtorelievingone'sownhurtsbutforgiving. B.Ifsomeoneslapsyouyoujustslapbackwhichwilllessenyourpain. C.Thesufferingswehavewitnessedorexperiencedwillliveoninourmemoriesforever. D.Afterbeinghurtifonewantstoexperiencehealingandfreedomheshouldforgetthehurt. 69.Whichofthefollowingstatementsistheclosestinmeaningtotheunderlinedsentence A.Inordertohelpothersweshouldstopforgivingandfightback. B.Thepurposeofourforgivingisnottohelpotherpeople. C.Ourforgivingisalsousefultohelpingothersthoughtheymayhavehurtus. D.Onlybyforgivingotherscanwehelpthemtobegoodpeople.
如图所示电路中已知电源电压保持不变小灯泡L的规格为“6V3W”滑动变阻器R的最大阻值为30ΩR0为定值电阻． 1小灯泡L正常发光时的电流为多少 2只闭合开关S1和S2将变阻器滑片从最左端a向右滑动当变阻器接入电路的阻值为4Ω时小灯泡L恰好正常发光则电源电压是多少 3只闭合开关S1和S3当滑片置于a时电压表示数为6V电流表示数为0.2A此时滑动变阻器消耗的电功率为1.2W当滑片向右滑动到另外某个位置时变阻器消耗的电功率仍然为1.2W试求在这个位置时电流表的示数I．
Theorangutan红毛猩猩themostinactiveofthegreatapeshasunusuallystableDNAtoo.Researchershavejustcompletedthesequencing序列oftheentiregenome基因组ofourorange﹣hairedrelativeandtheyhavefoundtotheirsurprisethatitsDNAhaschangedmuchlessdramaticallyovertimethanhasthatofhumansorchimpanzees.TheorangutanisveryuniquesaysDevinLockeastructuralgeneticistheadingtheorangutansequencingproject.Theorangutangenomehadoneotherbigsurprise.LockeandcolleaguessequencedsixSumatranandfiveBorneanorangutanswhichareclassifiedasdifferentspecies.Theapeshavebeenphysicallyseparatedforatleast21000years﹣thelasttimelandbridgesbetweenthetwoislandsexisted﹣andearlierstudiesestimatedthattheybecamedistinctspeciesmorethan1millionyearsago.ButthenewanalysisreportedonlinetodayinNaturerewriteshistory:itappearstheypartedwaysjust400000yearsago.MostpreviousstudiesusedsmallsetsofmarkersandalimitedamountofDNAsequencesaysLocke.Thestatisticalpowerissomuchgreaterwhenyouhavethewholegenomeavailable.Theorangutannowjoinschimpanzeesandhumansasthethirdgreatapetohaveitsgenomesequenced.TheorangutangenomeisawonderfulresourcesaysevolutionarygeneticistSvantePääbooftheMaxPlanckInstituteforEvolutionaryAnthropologyinLeipzigGermany.ItwillhelpclarifyhoweachpartofhumanandAfricanapegenomesarerelatedtoeachotherandevolved.Suchinsightsarealreadycomingin.Orangutansoriginatedsome12millionto16millionyearsagogivingtheirgenomesmuchmoretimetoevolvethanthoseofhumansandchimpanzeeswhichsplitintotheirownlineages血统5millionto6millionyearsago.Butacomparisonofthethreegenomesshowsthathumansandchimpanzeesloseorgainnewgenesattwicetherateoforangutans.ThereasonmayhavetodowithstretchesofDNAcalledretrotransposons.Thesekeydriversofevolutionjumparoundthegenomecreatingnewgenesdamagingexistingonesoralteringgeneregulation.ThenewdatarevealthatcommonretrotransposonsknownasAluelementshavemovedaroundtheorangutangenomemuchlessthantheyhaveinthehumanandchimpanzeegenomes.Idon'twanttosaythat‘Aluretrotranspositionevents'areshutoffinorangutansbutthey'vebeencoveredupsaysLocke.Theresearchersalsodiscoveredthatovertimethestructureoforangutanchromosomes染色体haschangedlittlewhichmaybelinkedtotheAluelementfinding.Otherresearchershavesuggestedthatthestrongandhealthystructuralvariationinhumansandchimpsmayhavestimulatedincreasedintelligence.ButLockenotesthatorangutansarealsohighlyintelligent.Iforangutanshavehadverylittlestructuralvariationmaybethisdecouplesstructuralvariationfromintelligencehesays.AseparatebutrelatedstudypublishedtodayinGenomeResearchreportsyetanotherunexpectedfindingfromacomparisonofthethreegreatapegenomes.AteamledbyMikkelH.SchierupandThomasMailundofAarhusUniversityinDenmarkbothco﹣authorsoftheNaturereportdiscoveredthatsomeregionsofthehumangenomemorecloselyresembletheorangutanthanthechimpanzee.ThisreflectsthefactthatatthetimehumanssplitofffromacommonancestorwithchimpsbothspecieshadthesameancestralorangutanDNA.Buthumansandchimpanzeeshaveevolvedseparatelyformillionsofyears.IntheprocesschimpsformysteriousreasonslostsomeorangutanDNAthathumanskeptpossessionof.Moresurprisesaresuretocomeasresearcherscomparethegenomesofevenmoreapes.Projectstosequencetheothertwogreatapesgorillasandbonobosareunderway.74.OrangutansfromtwoislandsSumatranandBorneanbecamedifferentspeciessince.A.atleast21000yearsagoB.over1millionyearsagoC.some12millionto16millionyearsagoD.400000yearsago75.WhichofthefollowingstatementsisTRUEaccordingtothispassageA.ComparedwiththeDNAoforangutanchimpanzee'sislesschangedovertime.B.Onlythreeapes'genomeshavebeensequenceduptonow.C.Humans'ancestorssteppedontheirwayofevolution12to16millionsyearsago.D.Chimpanzeesgainnewgenesfasterthanorangutansdoinevolution.76.Thereasonoforangutan'slittlechangeinDNAisthat.A.thisspeciesisnotasactiveinintelligenceashumansorchimpanzees.B.thenewlyidentifiedAluelementsisbelievedtohaveplayedaspecialroleC.AluretrotranspositionsinorangutanareshutoffduringthecourseofevolutionD.orangutan'slowintelligencefailstostimulatethechangeofitsDNA77.Someregionofhumangenomeismoresimilartothatoforangutanthanchimp'sbecause.A.humanandorangutansharethesameancestorbutchimpdoesn'tB.humansandchimpanzeeshaveevolvedseparatelyformillionsofyearsC.chimpsfailedtohangontoorangutanDNAforsomeunknownreasonbuthumandidn'tD.chimpsdidn'tactasactivelyashumansresultingintheirlosingsomecriticalorangutanDNA.
Asyougetolderitfeelsliketimetendstomovefaster.AsDanArielyexplainsoveratTheWallStreetJournalwetendtofallintofamiliarroutines25weageandthatmakestimemovequickly. Weperceivetimeassomethinglikeastackofmemoriessothelessnewexperiencesyouhavethe26likelyyouaretofillinthosememorieswithinterestingthings. Timedoesgobyormoreaccuratelyitfeelsasiftimeisgoingbymorequicklytheolderweget. Inthefirstfewyearsofourlivesanythingwesenseordoisbrandnewandmanyofourexperiencesareuniquesotheyremainfirmlyinourmemories.Butas27yearsgobyweencounterfewerandfewernewexperiences﹣bothbecausewe28accomplishalotandbecauseweareslavestoourdailyroutines. Forexampletrytoremember29happenedtoyoueverydaylastweekchancesarethatnothingextraordinaryhappenedsoyouwillbehard﹣pressedtorecallthespecificthingsyoudidonMondayTuesdayetc. WhatcanwedoaboutthisMaybeweneedsomenewappthatwillencourageustotryoutnewexperiencespointoutthingswe'veneverdonerecommenddisheswe'venevertastedandsuggestplaceswe'veneverbeen.Suchanapp30makeourlivesmorevariedencourageustotrynewthingsslowdownthepassageoftimeandincreaseourhappiness. 31suchanapparrivestrytodoatleastonenewthingeveryweek.It'snottoodifficulttopush32todonewthings.
晾晒三条相同的湿毛巾下列做法最有可能让衣架保持水平的是
12分在验证焦耳定律Q＝I2Rt中电热与电阻的定性关系时实验小组出现了如图三种电路连接情况已知R甲＜R乙．闭合开关三种电路的电流表指针均发生了偏转经过一段时间后观察并记录2根玻璃管内液面上升的高度△h小组实验报告汇总如下表请把表格空白处填写完整．
Pickingauniversityisatenseperiodofaskingyourselfwhichinstitutionismostrelevant.That'swhyuniversityrankingsplaysuchavitalroleinstudentssearchingfortheirnextacademicdirection.Rankingsarealsoaninescapablepartofthereputationandbrandimageofuniversities.Nouniversitywebsiteiscompletewithouttheclaimtobeinthetop100forsomethingorotherreportedtheBBC.Thereasonissimple:Rankingshelpthemtoattractstudentsstaffandresearchinvestment. Currentlytherearenumbersofuniversityrankingsandeachhasitsownlistofcriteria.Butthemaincategoriesarethesame:academicreputationgraduates'performanceandfacultyresources. Howeverexpertspointouttherankingprocessisn'tentirelyreliable.MarkKantrowitzaUSfinancialaidresearchersaiduniversityrankingsweremostlyjustforshow.HewroteinTheNewYorkTimes.Itmaygiveyourparentsbetterbraggingrightsbutthat'saboutit. Moreoverit'snotdifficulttoseethelimitationsofuniversityrankings.Manyrankingsfocusonthenumberoftimesresearchworkiscited引用byotherresearchers.IthelpsBritishandUSuniversitiestodominateglobalrankingsbecauseEnglishisthefavoredlanguageofacademiaJohnO'LearyamemberoftheQSacademicadvisoryboardtoldTheGunrdian.AlsorankingssuchasQSmainlyfocusonthequalitiesoftheuniversityratherthanitsstudents.AnyuniversityrankingislikelytohelpstudentsmakebetterdecisionsaboutwheretostudybuttheneedtobalancethemwithothermorehumanfactorsisalsoimportantsaidPhilMossaneducationandadmissionsconsultant.Advicefromgraduatesorcurrentstudentscanbeasvaluableinprovidingagenuineinsightintotheexperienceorqualityofaparticulardegreeprogram.Itcanalsoaddanelementthatrankingscanneverconvey﹣﹣theactualemotionofauniversityexperience. 32.WhydouniversitiesconsiderrankingsimportantA A.Rankingsmakethemmoreappealing. B.Rankingsarestudents'onlyreference. C.Rankingscanincreasetheiracademiclevel. D.Rankingshelpthemcompletetheirwebsites. 33.WhatdoestheunderlinedItinparagraph4refertoC A.Acadenucresearchwork. B.Thenumberofresearches. C.Thewayofrankinguniversities. D.Thelimitationofuniversityranking. 34.AccordingtoJohnO'LearywhathelpsBritishandUSuniversitiesrankwellA A.ThewideuseofEnglishinacademia. B.Theiroutstandingqualities. C.Theirgraduates'excellentperformance. D.Theacademia'sfavortothem. 35.BesidesrankingwhatdoesPhilMosssuggestyoushouldrefertoifyou'repickingauniversityD A.Investmentineducation. B.Guidancefromprofessors. C.Informationonwebsites. D.Suggestionsfromstudents.
小明参加科技节“掷飞机”比赛该项目的规则是纸飞机掷出后在空中滞留的时间越长成绩越好．查阅资料得知纸飞机在空中滞留的时间与其形状质量出手速度和出手角度有关．小明认为还可能与纸飞机表面的粗糙程度有关．为了验证自己的猜想小明准备了以下器材进行实验研究 发射器如图秒表剪刀面积质量大小和表面粗糙程度不同的两种纸AB各若干张同种纸正反面粗糙程度相同． 1发射器的弹簧压缩得越短释放后纸飞机获得的速度越大其原因是． 2写出本实验的主要步骤．
如图是小敏设计的汽车尾气中CO排放量的检测电路．当CO浓度高于某一设定值时电铃发声报警．图中气敏电阻R1阻值随CO浓度的增大而减小．下列说法正确的是
窗玻璃上趴着一只壁虎如图水平向右推窗当壁虎随窗玻璃一起向右匀速移动的过程中壁虎受到摩擦力的方向是
这部滑稽的电影的确分散了我注意力让我暂时忘记了这些难题.which.
NotbeingsurewhereIwanttostartthisIwillsaythatIlostmymombackinAprilofthisyear.Shewasninety﹣two.41Iwasnotexpectingherto42andIdon'tthinkshewasexpectingiteither.Iwasveryclosetomymombeinganonlychild.Wedidhave43onthesurfacebutwestillhadacloserelationship44those. Beingnewlymarriedlessthanayearandhavingmovedacoupleoftimes45Ihavehadmorechangesrecentlyinmylifethanatanyotherpointofmyfifty﹣fouryears.StabilityisoneofthegiftsthatMom46meandithadsomany47thatIwasn'tawareofuntilnow.MyhusbandandIhavemadesome48toMom'shomeandwillbemovingattheendofnextweek.Itisnowourhomebutitstillhasmy49heartinit.It'swhereIgrewupandtherearemany50thatwilllivetherewithus.AtthesametimeIamlookingforwardto51someveryhappyandmemorableoneswithmyhusband. Mom52suchabigpartinmylife.Ourliveswere53wovenbecauseshegavemehervalueswhichhavebecomestrongly54inthewomanIamtoday.Idon'thaveanychildrenwhomIcould55theseonto.HoweverMother'svaluesaffectmeeverydaywiththe56IhavewithotherswhetherIknowthemornot.IhopeMomwouldbe57ofwhoIamwhatI'vebecomebecauseofherandof58Iamgoingtolivewithmy59.ShegavemeeverythingIneededtoknowinlife:respectothersandgivehelptootherswho60itmost.IloveyouMomandIwillneverforgetyou. 41.A.However B.Otherwise C.Moreover D.Though 42.A.passout B.passaway C.passby D.passdown 43.A.promises B.agreements C.differences D.similarities 44.A.intermsof B.incaseof C.inneedof D.inspiteof 45.A.once B.since C.though D.either 46.A.saved B.brought C.gave D.taught 47.A.ideas B.thoughts C.meanings D.benefits 48.A.studies B.decisions C.changes D.remarks 49.A.son's B.father's C.mom's D.husband's 50.Amemories B.chances C.choices D.dreams 51.A.receiving B.promising C.making D.supplying 52.A.affected B.played C.controlled D.managed 53.A.brightly B.lightly C.roughly D.tightly 54.A.intended B.designed C.rooted D.admitted 55.A.hold B.pass C.drive D.reply 56A.contact B.interest C.trouble D.effect 57.A.free B.proud C.full D.certain 58.A.what B.where C.why D.when 59.A.life B.children C.husband D.time 60.A.hunt B.need C.treat D.consider
小明制作了一个如图所示的简易气压计．将橡皮膜平铺在敞口容器上并用胶带绑紧．检查气密性后将吸管的A端粘在橡皮膜中心B端靠近卡纸的M处．外界气压的变化会引起橡皮膜凹凸程度的变化从而使吸管绕O点转动指示气压大小变化．外界气温的变化对容器内气压的影响极小 1检查气密性时将绑有橡皮膜的容器浸没在水中轻压橡皮膜如果观察到则气密性不好． 2小明将该气压计从甲地带到乙地发现吸管B端的指向从M处变为N处．则甲乙两地气压较大的是．
温州地区常受台风侵袭为测量风速小明设计了一台简易风速仪其工作原理如图甲所示．装有挡风板和滑片P的轻质滑块与轻质弹簧套在滑杆MN上弹簧左端固定右端与滑块相连．挡风板的挡风面积为0.2米2均匀电阻丝AB长为20厘米阻值为10欧电源电压U0恒为6伏保护电阻R0为14欧电压表量程0～3伏．弹簧弹力F与弹簧长度改变量x的关系如图乙所示．无风时滑片P在A处有风时滑块移动稳定后读出电压表示数计算并查阅下表数据可知风速及风级． 表中风压p是指与风向垂直的受风面上单位面积增加的压力即单位面积受到的风力．测量时保证风垂直吹在挡风板上不计一切摩擦阻力． 1在滑片P左移的过程中电路的总电阻．选填“变大”“不变”或“变小” 2当电压表示数U为2伏时风速仪所测的风为几级写出计算过程 3小明想在风速仪的电压表上直接标出风速查阅资料后获知该挡风板所受的风力与风速的平方成正比．经计算他画出了风速v与电压表示数U的关系曲线如图丙所示．后因保护电阻R0损坏他将其换成了阻值为5欧的电阻请你在图丙坐标系中大致画出更换电阻后的风速v与电压表示数U的关系曲线并在曲线上标出所能测量的最大风速的对应点Q．
众所周知大量砍树对自然平衡有灾难性的影响.As.
小敏对“物体在水中浸没前受到的浮力是否与浸入深度有关”进行了研究． 1将一长方体金属块横放部分体积浸入水中时在液面所对的烧杯壁作一标记线读出弹簧测力计的示数F甲如图甲为牛再把金属块竖放浸入同一杯水中当时读出弹簧测力计示数F乙如图乙．比较发现F乙＝F甲小敏得出浸没前物体受到的浮力与浸入深度无关． 2图中两种状态时金属块底部受到水的压强p甲p乙选填“大于”“等于”或“小于”．
如图所示一个小物体以初速度v0冲上某一粗糙斜面最后停在斜面上忽略空气作用对该过程的描述正确的是
AroundfouryearsagoIreceivedacallfromtheprincipalofourschoolastotheParentsViewtalkthenextmorning.Heaskedmetospeaktothegroup.Afterthecallmywholebodybecamefeverishandpanicky.Thetimefromhiscalltothenextmorningseemedlikeyears.ThewholenightIcouldnotsleepwithmanyominousapprehensionsinmind.OneofthemwastocalltheprincipalwithregretandtellhimthatIcouldnotcome.FinallyIgatheredsomecourage.IthoughtIfImissthisopportunitysurelytheschoolwillneverinvitemeagaintoanyoftheirprograms.Ireachedtheschoolintime.Beforemyturncamemywholebodywastrembling.WhenmyturncameandIstartedspeakingmyheartbeatincreasedandmymouthwentdry.Iwasn'tevenabletoreadthewrittenspeechproperly.IwasnotawareofwhereIwasstandingandwhatIwasreading.ThatwasthedaywhenIrealizedmybiggestweaknessPublicSpeaking.AftermyspeechImetwiththeprincipalandexplainedwhathappenedtome.Hetoldmethatthishappenstoeveryone.Evengreatspeakerfacedthesamethingswhentheystarted.HesuggestedthatIcomeagainnexttime.AroundonemonthlaterIwasinvitedtorefertoatopiconMotivation.ThistimeIwasfeelingcomfortable.MyspeechwasnotonlyappreciatedbytheprincipalaswellastheteachersbecauseIwasabletogetmyideaacrosstothem.Theyencouragedandpraisedmyefforts.AfterdeliveringissuccessfullyIbecamemoreconfident.lsaidtomyselfIfIcanspeakinfrontofsuchalearnedaudienceliketheprincipalwhoeducatesothersIcannowspeakinfrontofotherstoo.IstarteddeliveringlecturesinmyplantonvarioustopicslikeSelfMotivationPersonalityDevelopmentPersonalExcellenceSpokenEnglishandPresentationSkills.Thishasbecomeapassionforme.Ilearnedthateverythingispossibleifwehavethecouragetotakethefirststep.24.WhichofthefollowingisthehesttitleforthepassageAA.PracticeMakesaManaBetterSpeechmakerB.PublicSpeakingMakesaManEmbarrassed.C.PrincipalProvidestheBestChances.D.SpokenEnglishDevelopsinMaltingSpeeches.25.TheauthorhadbadfeelingsbeforethespeechbecauseD.A.hedislikedtheideaofgivingalectureB.hehadgotahighfeverbeforethatC.heregrettedacceptingtheinvitationD.hefearedhecouldn'tperformitproperly26.WhatdoestheunderlinedpartominousapprehensionsinthefirstparagraphmeanBA.Unluckyopportunities.B.Negativeideas.C.Curiousviews.D.Happycomments.27.WhatcanweconcludefromthepassageCA.Nothingistobegotwithoutpainsbutpoverty.B.Knowledgemakeshumbleignorancemakesproud.C.Ajourneyofathousandmilesbeginswithasinglestep.D.Necessityisthemotherofinvention.
如图所示在拉力F作用下一个重600N的物体以0.1m/s的速度沿水平地面向右匀速直线运动了10s已知滑轮组的机械效率为80%在此过程中拉力F做了150J的功则下列说法中正确的是
如图所示固定的轻弹簧下端用细线竖直悬挂一条形磁体当下方电路闭合通电后发现弹簧长度缩短了请在括号中标出螺线管下端的极性N或S和电源上端的正负极+或﹣．
如图中所示电路中已知定值电阻R1＝20Ω开关闭合后两个完全相同的电流表A1A2指针均指在同一位置如图乙所示则此时通过R1的电流为A在10s内R2产生的热量为J．
我们每天都在产生大量垃圾合理分类和利用垃圾是我们面临的一个重大课题．某垃圾处理厂处理垃圾时提炼出了200kg燃料油若燃料油的热值为4.0×107J/kg则这些燃油完全燃烧放出的热量为J燃料油燃烧时发热燃料油的化学能转化为能．
在测量小灯泡的电功率的实验中实验室提供如下器材电源电压恒为6V电压表和电流表各一个额定电压为2.5V的待测小灯泡L电阻约为10Ω滑动变阻器两个R甲10Ω1AR乙50Ω0.5A开关S导线若干．1该实验的原理是电功率P＝2实验中应选用的滑动变阻器是选填R甲或R乙3选用滑动变阻器后请你根据以上器材设计一个测量小灯泡电功率的实验电路图并画在图甲的虚线框内4某小组在实验中记录了3组小灯泡的电流随电压变化的情况如图乙所示完成实验后小组进一步求得该小灯泡正常发光时的电阻为Ω保留到小数点后一位5另一小组实验时发现电流表已经损坏为了测出该小灯泡的额定功率小组在实验室选了一个10Ω的电阻R0和一个单刀双掷开关设计了如图丙所示的电路并完成了该实验电源电压不变①闭合开关SS1接b调节滑动变阻器R使小灯泡正常发光记录电压表示数U1．②闭合开关S滑动变阻器滑片保持不动S1接a读出此时电压表示数为U2．则小灯泡额定功率P额＝用R0U1U2表示．
雾天能见度低骑车易发生交通事故要减速慢行． 1雾天空气中会形成大量水珠．该过程发生的物态变化是 2小明要为自行车设计一种“雾灯”以提示过往的行人和车辆．要求工作时灯泡能持续交替闪烁忽 略弹性衔铁和电磁铁线圈电阻下列电路中符合设计要求的是．
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