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图甲为一列简谐横波在t=0.10s时刻的波形图,P是平衡位置为x=1m处的质点,Q是平衡位置为x=4m处的质点,图乙为质点Q的振动图象,则下列说法正确的是( )
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如图所示实线是沿x轴传播的一列简谐横波在t=O时刻的波形图虚线是这列波在t=0.2s时刻的波形图则
这列波的周期可能是1.2s
这列波的波长为12m
这列波可能向左传播了14m
这列波的波速可能是40m/s
如题II图为一列沿X.轴负方向传播的简谐横波实线为t=0时刻的波形图虚线为t=0.6s时的波形图波的
一列简谐横波沿x轴传播如图所示实线为t=0时刻的波形图虚线表示经过Δt=0.2s后的波形图.1求波速
如图所示一列简谐横波沿x轴传播实线为t1=0时刻的波形图虚线为t2=0.25s时刻的波形图已知这列波
2m/s,向左
2m/s,向右
6m/s,向左
6m/s,向右
图甲为一列简谐横波在t=0时刻的波形图图乙为质点P.以此时刻为计时起点的振动图象1简谐横波的传播方向
一列沿x轴传播的简谐横波某时刻的波形图象如图中的实线所示再经t=0.2s的波形图如图11中的虚线所示
图1为一列向左传播的简谐横波在某一时刻的波形图判断波形图上P点的振动方向.
图a为一列简谐横波在t=0.10s时刻的波形图P.是平衡位置在x=1.0m处的质点Q.是平衡位置在x
如图所示实线是沿x轴传播的一列简谐横波在t=0时刻的波形图质点P.恰在平衡位置虚线是这列波在t=0.
这列波可能是沿x轴正方向传播的
t=0时,x=4 cm处质点P.的速度沿x轴负方向
质点P.在0.2s时间内经过的路程为8 cm
质点P.在0.2s时刻速度方向与加速度方向相同
如图所示为一列沿x轴负方向传播的简谐横波实线为t=0时刻的波形图虚线为t=0.6s时的波形图波的周期
波的周期为2.4 s
波的速度为 m/s
在t=0.5s时,Q.点到达平衡位置
在t=0.5s时,Q.点到达波峰位置
在图中实线是0时刻一列简谐横波的波形图虚线是0.2s时该波的波形图求这列波的周期和波速
一列简谐横波如图所示波长λ=8m实线表示t1=0时刻的波形图虚线表示t2=0.005s时刻第一次出现
一列沿x轴传播的简谐横波某时刻的波形图象如图中的实线所示再经t=0.2s的波形图如图中的虚线所示.则
一列简谐横波在t=0.8s时刻的波形图象如下图乙所示波上A.质点的振动图象如图甲所示①判断该波的传播
如图所示是一列简谐横波在t1=0时刻的波形图已知这列波沿x轴正方向传播波速为20m/s试画出t2=0
如图所示实线是一列简谐横波在t1时刻的波形图虚线是在t2=t1+0.2s时刻的波形图.若波速为35m
图4所示为一列沿x轴负方向传播的简谐横波实线为t=0时刻的波形图虚线为t=0.6s时的波形图波的周期
波的周期为2.4 s
在t=0.9 s时,P.点沿y轴正方向运动
经过0.4 s,P.点经过的路程为4 m
在t=0.5 s时,Q.点到达波峰位置
一列简谐横波在t=0.4s时刻的波形图象如下图乙所示波上A.质点的振动图象如图甲所示①判断该波的传播
如图所示为某时刻一列简谐横波的波形图象已知此列波的振动周期为4s由图可知这列波的传播速度大小为m/s
如图所示实线是沿x轴传播的一列简谐横波在t=0时刻的波形图虚线是这列波在t=0.2s时刻的波形图则
这列波的周期可能是1.2s
这列波的波长为12m
这列波可能向左传播14m
这列波的波速可能是40m/s
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如图所示将系在细线下的小球拿至A点然后释放小球将在AC两点之间往复摆动如果不考虑空气对小球的阻力下列分析中正确的是
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如图所示电路中甲乙两处分别接入电流表或电压表.当S闭合后为使两灯均能发光则
假定你是李华你在网上看到你所在城市的一个英语培训中心拟招收暑期助教请根据以下要点写一封英语申请信.内容包括1.申请原因2.自我优势口语能力组织能力沟通能力3.希望获准. 注意1.词数100左右 2.可以适当增加细节以使行文连贯 3.信的开头和结尾已给出不计入总词数. 参考词汇助教teachingassistant DearSir/Madam I'mgladtoseeyouradvertisementontheInternet. . Yourssincerely LiHua.
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.每处错误仅涉及一个单词的增加删除或修改. 增加在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. 修改在错的词下画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. OnedayIwascookinginthekitchenwhilethetelephonerang.Iwenttoansweritimmediately.ShewasmyclosefriendLisa.Whenweweretalkingonaphonethefirealarmsounded.Irunbacktothekitchen.Theroomwasfullsmokeandthebeefwasbadburnt.Iquicklyturnedoffthegasopeningallthewindowsandthenwentoutofthehouse.Tomygreatsurprisestwofireengineswereoutsidemyhouse.Iwasratherworried.Itoldaboutthefirementhatitwasmycarelesscookingwhichcausedtheheavysmoke.
HowSuperAreSupermarkets? Buyingeweek'sgroceriesistiring.Youwanttogetitoveranddonewithquicklysoyouheadforthenearestsupermarketyoufindeverythingyouneedunderoneroofandyoufeelgladthatthosedaysofgoinginandoutofdifferentshopsinthehighstreetareover.Supermarketsseemtobeabigplus.Thereisadownsidethough. IntheUK90%ofallthefoodpeopleconsumeisboughtat5differentsupermarketchains.Thismakesthesecompaniesextremelypowerfulwhichletsthemusetheirhugebuyingpowertosqueezesmallsupplierstogetthebestdeal.Milkisagoodexample.Supermarketsliketousethingslikemilkwhichisthetopofalmosteveryone'sshoppinglisttoattractcustomers.Toofferthelowestpricepossibletotheconsumerthesupermarketsforcedairyfarmerstosellmilkatlessthanthecostofproduction.Supermarketsguaranteetheirgoodprofitswhilefarmersareleftstrugglingtomakeendsmeetandthetaxpayerpaystosupportthesystemwithoutevenknowingit. Itwouldbeniceiflocalgrocerssupportedlocalagriculture.Butforthebigsupermarketsthisjustdoesn'tmakesense.Supermarketsdon'twantlittlefarmersthinkingtheycandecideprices.Sosupermarketshavestartedaglobalsearchforthecheapestpossibleagriculturalproduce.Inmanysupermarketsitisdifficulttofindanythingwhichisproducedlocally. UKfarmersusedtogrowalotofapples.Notanymore.In199936%ofappleswereimported.By2015thefigurehadrisento80%andthedomesticproductionofappleshadfallenbytwothirds.TheconsumermightjustbehappytogetareasonablypricedmealmadeupoffoodsfromThailandSpainItalyandZambiabutweshouldalsobearinmindtheInfluenceonlocalproducers. Thenthere'spackaging.Supermarketslikeeverythingtobepackedandwrappedsoitcanbepiledneatlyonshelves.Supermarketsproducenearly10milliontonsofwastepackagingintheUKeveryyearofwhichless5%isrecycled.Somesupermarketsmakesurethatlargerecyclingbinsareobviousintheircarparksshowingthattheyareenvironment﹣friendly.Butthatisjustanimage. Whenanewsupermarketisplannedthereareclaimsaboutthenumberofnewjobsthatwillbecreated.Unfortunatelythenumberofjobslostintheareaislargerthanthenumberofnewpositionsinthesupermarket.Onaverageeachnewsupermarketleadstothelossof276jobs. Howeverthemodernworldisallaboutshoppingandthefreedomtobuywhateveryouwhatsoitwouldbeimpossibletostoppeopleshoppingatsomeparticularkindofshop.Butsomemeasuresdoneedtobetakenwhensmallsuppliersloseprofitslocalproducerssuffersealevelsriseandjobsarelostanywaywecan'tjustcareaboutafreecarparkandspecialoffers. 1Theauthormentionsmilkinparagraph2toexplainhowsupermarkets. A.harmsmallsuppliers‘benefits B.supportlocaldairyfarmer C.cheatthetaxpayers D.providecustomerswiththecheapestproduct 2Accordingtothepassagesupermarketskeeppriceadvantageby. A.competingagainsteachother B.reducingproducttax C.purchasinglocalproducts D.importingforeignproducts 3Whatistheauthor'sattitudetowardssupermarkets? A.Doubtful B.Sympathetic C.Critical D.Cautious
MyRealParentsBiologyistheleastofwhatmakessomeoneamother.﹣﹣﹣﹣﹣OprahWinfreyIdon'tlookliketherestofmyfamily.AsamatteroffactI1outquiteabitwithmyyellowskinandblackeyes.WhenpeopleseeustogetheritisclearthatIam2.IamhappytohavesuchalovingandcaringfamilybutsometimesIwishIknewwhomybirthparentsare.Myfriendsoftenask'Areyou3thatyoudon'tknowyourrealparents?'Iknowthattheyarejustcuriousandconcernedaboutme﹣﹣﹣I'mfine.Forthemostpart﹣﹣﹣﹣4Ifeltlikethere'ssomethingmissingmylifelikeagiant5inmyheart.MymotherlistenswhenItellheraboutmy6andshefeelsthatitisimportantformetobeintouchwithmy7.BecauseofthissheandIgotoChineseHeritageCampeachyear.CHCisatwo﹣daycamp8hundredsofadoptedkidslikemespendtimewitheachother.We9abouthowitfeelstotheadoptedandweparticipateinfunoutdooractivities.It's10becausewecantalkaboutourfeelings.ItmakesmefeellikeIamnot11andthatthereissomeoneouttheregoingthroughthesamefeelings.Whetherwe'retalkinglaughingcryingordancing.CHCisalwaysanexperienceto12.IadoreallofthenewpeopleImeetandIwillkeeptheminmyheart13becauseitalwaysfeelsgoodtoknowtherearepeopleoutjustlikeme.Camphas14thewayIlookatthings.Eachyearseemstoopenupnewsurprisesadventuresandfriendships.CHC15metolearnthatbeingadopteddoesn'tmeanthatI'mstrangeitjustmeansthatIwasn'tbornintothe16Ilivewith.Beingadoptedwon'tmakemyparentslovemeanyless.17toChineseHeritageCampnowwhenpeopleaskme'Areyousadyoudon'tknowyourrealparents?'Icansafelyanswer'MaybeIdon'tknowwhomybirthparentsareand18makesmealittlesad.ButIdoknowthatI19withmyrealparentsinarealhousewitharealfamilyandI20.Mylifejustthewayitis.'1A.work B.give C.watch D.stand2A.followed B.honored C.believed D.adopted3A.sad B.ashamed C.surprised D.curious4A.and B.but C.so D.or5A.disease B.wish C.hole D.plan6A.dreams B.suggestions C.feelings D.complaints7A.school Bhometown Cculture D.relatives8A.where B.when Cwhy D.which9A.think B.talk C.write D.look10A.terrible B.funny C.hard D.great11A.happy B.alone C.silent D.alive12Aremember B.describe C.provide D.learn13A.sometimes B.forever C.soon D.later14A.made Bfound C.changed D.Cleared15A.forced B.hoped C.taught D.asked16A.family B.world C.friends D.kids17A.thanks B.Congratulations C.wishes D.Greetings18A.who B.which C.that D.what19A.compare B.deal C.agree D.live20A.enrich B.love C.regard D.improve
Doeshappinesshaveascent? Whensomeoneishappycanyousmellit? Youcanusuallytellwhensomeoneishappybasedonseeingthemsmilehearingthemlaughorperhapsfromreceivingabighug.Butcanyoualsosmelltheirhappiness?SurprisingnewresearchsuggeststhathappinessdoesindeedhaveascentandthattheexperienceofhappinesscanbetransmittedthroughsmellreportsPhys.org. Forthestudy12youngmenwereshownvideosmeanttobringaboutavarietyofemotionswhileresearchersgatheredsweatsamplesfromthem.Allofthemenwerehealthyandnoneofthemweredrugusersorsmokersandallwereaskedtoabstainfromdrinkingoreatingsmellyfoodsduringthestudyperiod. Thosesweatsampleswerethengivento36equallyhealthyyoungwomentosmellwhileresearchersmonitoredtheirreactions.Onlywomenwereselectedtosmellthesamplesapparentlybecausepreviousresearchhasshownthatwomenhaveabettersenseofsmellthanmenandarealsomoresensitivetoemotionalsignaling﹣thoughit'sunclearwhyonlymenwerechosentoproducethescents. Researchersfoundthatthebehaviorofthewomenaftersmellingthescents﹣particularlytheirfacialexpressions﹣indicatedarelationshipbetweentheemotionalstatesofthemenwhoproducedthesweatandthewomenwhosniffedthem. Humansweatproducedwhenapersonishappybringsaboutastatesimilartohappinessinsomebodywhobreathesthissmellsaidstudyco﹣authorGunSeminaprofessoratKocUniversityinTurkey. Thisisafascinatingfindingbecauseitnotonlymeansthathappinessdoeshaveascentbutthatthescentiscapableoftransmittingtheemotiontoothers.Thestudyalsofoundthatotheremotionssuchasfearseemtocarryascenttoo.Thisensurespreviousresearchsuggestingthatsomenegativeemotionshaveasmellbutitisthefirsttimethishasprovedtobetrueofpositivefeelings. Researchershaveyettoisolate分离exactlywhatthechemicalcompoundforthehappinesssmellisbutyoumightimaginewhatthepotentialapplicationsforsuchafindingcouldbe.Happinessperfumesforinstancecouldbeinvented.Scenttherapies香味疗法couldalsobedevelopedtohelppeoplethroughdepressionoranxiety. Perhapsthemostsurprisingresultofthestudyhoweverisourbroadenedunderstandingofhowemotionsgetcommunicatedandalsohowourownemotionsarepotentiallymanagedthroughoursocialcontextandtheemotionalstatesofthosearoundus. 1Whatisthemainfindingofthenewresearch? A.Pleasantfeelingscanbesmeltout. B.Negativeemotionshaveasmell. C.Menproducemoresweats. D.Womenhaveabettersenseofsmell. 2TheunderlinedpartabstainfrominParagraph3probablymeans. A.continue B.practice C.avoid D.try 3Whatistheapplicationvalueofthenewresearch? A.Perfumescouldhelppeopleunderstandeachother. B.Somesmellscouldbecreatedtoimproveourappearance. C.Perfumescouldbeproducedtocurephysicaldiseases. D.Somesmellscouldbedevelopedtobetterourmood. 4Wecanlearnfromthelastparagraphthat. A.happinesscomesfromascentofsweat B.socialsurroundingscaninfluenceouremotions C.peopleneedmoreemotionalcommunication D.positiveenergycandeepenunderstanding
探究影响电磁铁磁性强弱的因素时按图示电路进行实验.逐渐增大电路中的电流进行多次实验每次都能观察到电磁铁甲吸引大头针的数目比乙多.此现象能够说明
ThreeyearsagoaflashoflightningalmostdestroyedLynDiana‘shouseinAberdeen﹣﹣﹣withhertwochildreninside.Therewasahugerainstormshesaysrecallingtheterrifyingexperience.MybrotherandIwereoutsidemakingeveryefforttostopfloodwaterfromcominginthehouse.SuddenlyIwasthrowntothegroundbyaverylargebang.WhenIpickedmyselfuptheroofandthewholeupperstoreyofthehousehadbeendestroyed.Thedoorwasblockedbybrokenbricksbutweforcedourwayinandfoundthechildrenthankfullyunharmed.LaterIwastoldthattobestruckbylightningisachanceinmillion.Infactit'satonechancein600000.EvensoDr.MarkKeysofAERTechnologyanorganizationthatmonitorstheeffectsoflightningthinksyoushouldbecareful.Headvisesanyonewhoisunluckyenoughtobecaughtinastormtogetdownonthegroundandbendintoaballmakingyourselfassmallaspossible. NancyWilderwasplayinggolfataclubinSurreywhenshewashitbyaflashoflightning.Mrs.Wilder'sheartstoppedbeatingbutshewasbroughtbacktoconsciousnessandafterafewdaysinhospitalwhereshewastreatedforburnstoherheadhandsandfeetshewaspronouncedfitagain.Sincethattimeshehasbeenacompletelyfair﹣weathergolfer.Infactagolfcourseisoneofthemostdangerousplacestobeduringathunderstorm.Thebestplacetobeisinsideacar! HaroldDealaretiredelectricianfromSouthCarolinaUSAwasstruckbylightning26yearsago.Heseemedtobeunhurtbutitlaterturnedoutthatthestrikehaddamagedthepartofthebrainwhichcontrolsthesensationoftemperature.SincethenthefreezingSouthCarolinawintershaven'tbotheredHarold. 1WhatdamagedidtherainstormcausetoMrs.Diana'sfamily? A.Herhousewasfloodedandfelldown. B.Herchildrenwereseriouslyillandhurt. C.Thetopstoreyofherhousewascompletelydestroyed. D.Thedoorinthehousewasbrokenbyaverylargebang. 2WhatdidMrs.Wilderdoaftersurvivingthelightningstrike? A.Sheplayedgolfonlyonfinedays. B.Sheneverplayedgolfagain. C.Sheoftenwenttoseeadoctor. D.Shenevertookanymedicine. 3WhatdoweknowaboutHaroldDealfromthelastparagraph? A.Thelightningstrikedidnotdoanyharmtohim. B.Thelightningstrikeburnthishairandskinterribly. C.HesufferedalotfromthefreezingcoldinSouthCarolina. D.Hewasn'tsensitivetotemperaturesafterthelightningstrike. 4Whatcanweconcludefromthepassage? A.Ithappensquiteoftenthatlightningstrikespeopleduringastorm. B.Duringathunderstormyouaresaferinyourhousethaninyourcar. C.Duringathunderstormitisthesafestforyoutostayunderabigroundball. D.Ifyouarecaughtinastormyou'dgetdownaslowaspossibleontheground.
流量表示单位时间内通过某一横截面的流体的体积.如图所示水流在粗细均匀的水平管道内向右匀速流动设水流速度为v管内通道的横截面积为S.取一段管道AB水从A端流到B端所用时间为t则通过管道AB的水的流量为.在时间t内流过管道AB的水的质量为.水的密度用ρ表示
如图所示的是一个重为4.5N的足球在空中飞行时的情景.请在图中作出足球所受重力的示意图.
如图1所示质量不计的弹簧竖直固定在水平面上t=0时刻将一金属小球从弹簧正上方某一高度处由静止释放小球接触弹簧并将弹簧压缩至最低点形变在弹性限度内然后又被弹起离开弹簧上升到一定高度后又下落如此反复.通过安装在弹簧下端的压力传感器测出该过程中弹簧弹力F随时间t变化的图象如图2所示不计空气阻力. 1在整个运动过程中小球的机械能填“守恒”或“不守恒” 2小球动能最小的时刻是填t1t2或t3 3在t2~t3这段时间内小球的动能填“先增大后减小”“先减小后增大”“一直增大”“一直减小”
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