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我国未来将建立月球基地,并在绕月轨道上建造空间站.如图,关闭动力的航天飞机在月球引力作用下经椭圆轨道向月球靠近,并将与空间站B处对接.已知空间站绕月轨道半径为r,周期为T,万有引力常量为G,下列说法...
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我国未来将建立月球基地并在绕月轨道上建造空间站如图所示关闭动力的航天飞机在月球引力作用下向月球靠近
图中航天飞机正加速飞向B处
航天飞机在B处由椭圆轨道进入空间站轨道必须点火减速
根据题中条件可以算出月球质量
根据题中条件可以算出空间站受到月球引力的大小
2009年美国重启登月计划打算在绕月轨道上建造空间站如下图所示关闭动力的航天飞机在月球引力作用下沿椭
根据题中条件可以算出空间站受到月球引力的大小
航天飞机在II轨道上向P处运动过程中加速度逐渐变小
航天飞机在I轨道过P点的速度比II轨道通过P点的速度大
根据题中条件可以算出月球质量
我国未来将建立月球基地并在绕月轨道上建造空间站.如图所示关闭动力的航天飞机在月球引力作用下向月球靠近
图中航天飞机正加速飞向
处 B.航天飞机在B.处由椭圆轨道进入空间站轨道必须点火加速
根据题中条件可以算出航天飞机的质量
根据题中条件可以算出空间站受到月球引力的大小
我国未来将建立月球基地并在绕月轨道上建造空间站.如图2所示关闭动力的航天飞机在月球引力作用下向月球靠
图中航天飞机正加速飞向
处 B.航天飞机在B.处由椭圆轨道进入空间站轨道必须点火减速
根据题中条件无法算出月球质量
根据题中条件可以算出空间站受到月球引力的大小
我国未来将建立月球基地并在绕月轨道上建造空间站.如图5所示关闭发动机的航天飞机
在月球引力作用下沿椭圆轨道向月球靠近,并将在椭圆的近月点
处与空间站对接.已知空间站绕月轨道半径为r,周期为T.,引力常量为G.,月球的半径为R..下列判断正确的是 ( )
图5 A.航天飞机到达B.处由椭圆轨道进入空间站轨道时必须减速 B.图中的航天飞机正在加速飞向B.处
月球的质量M.=
月球的第一宇宙速度v=
我国未来将建立月球基地并在绕月轨道上建造空间站.如图所示关闭动力的航天飞机在月球引力作用下向月球靠近
图中航天飞机正匀速率飞向
处 B.航天飞机在B.处由椭圆轨道进入空间站轨道必须加速
根据题中条件可以算出月球质量
根据题中条件可以算出空间站受到月球引力的大小
我国未来将建立月球基地并在绕月轨道上建造空间站如图所示关闭动力的航天飞机在月球引力作用下向月球靠近并
图中航天飞机正加速飞向
处B.航天飞机在B.处由椭圆轨道进入空间站轨道必须点火减速
根据题中条件可以算出月球质量
根据题中条件可以算出空间站受到月球引力的大小
2009年美国重启登月计划打算在绕月轨道上建造空间站如图所示关闭动力的航天飞机在月球引力作用下沿椭圆
根据题中条件可以算出月球质量
航天飞机在椭圆轨道和空间站轨道上运动机械能相等
航天飞机向P.处运动过程中速度逐渐变小
航天飞机向P.处运动过程中加速度逐渐变大
我国未来将建立月球基地并在绕月轨道上建造空间站如图所示关闭发动机的航天飞机在月球引力作用下沿椭圆轨道
航天飞机到达
处由椭圆轨道进入空间站轨道时必须减速B.图中的航天飞机正在加速地飞向B.处
月球的质量为
月球的第一宇宙速度为
我国未来将建立月球基地并在绕月轨道上建造空间站.如图所示关闭动力的航天飞机在月球引力作用下向月球靠近
图中航天飞机正加速飞向
处 B.航天飞机在B.处由椭圆轨道进入空间站轨道必须点火减速
根据题中条件可以算出月球质量
根据题中条件可以算出空间站受到月球引力的大小
我国未来将建立月球基地并在绕月轨道上建造空间站如图所示关闭发动机的航天飞机在月球引力作用下沿椭圆轨道
航天飞机到达
处由椭圆轨道进入空间站轨道时必须加速 B.航天飞机正在由A.处加速飞向B.处
月球的质量为
月球的第一宇宙速度为
我国未来将建立月球基地并在绕月轨道上建造空间站.如图所示关闭动力的航天飞船在月球引力作用下向月球靠近
图中航天飞机正减速飞向
处 B.航天飞船在B.处由椭圆轨道进入空间站轨道必须点火减速
根据题中条件可以算出月球质量
根据题中条件可以算出空间站受到月球引力的大小
我国2007年10月24日发射的嫦娥一号月球卫星经过四次变轨后其绕地球运行的椭圆轨道的远地点D.靠近
图中航天飞机在飞向E.处的过程中,月球引力做正功,所以在E.处由椭圆轨道可直接进入空间站圆周轨道,不需要变速。
如果忽略月球引力的影响,“嫦娥一号”通过远地点A.,B,C,D时,在D.点线速度最大,加速度最小。
根据题中条件可以算出月球质量
如果忽略月球引力的影响,“嫦娥一号”通过远地点A.,B,C,D时,和地球系统所决定的机械能,A.点最大,D.点最小
2010年10月1日我国成功发射嫦娥二号探月卫星不久的将来我国将建立月球基地并在绕月轨道上建造空间站
处航天飞机在月球引力作用下正沿椭圆轨道向月球靠近,并将与空间站在
处对接。已知空间站绕月轨道(设为圆)离月球表面高度h、周期为T.,月球质量为M.,万有引力常量为G.,下列说法正确的是 A.图中航天飞机由A.到B.的过程速度越来越小 B.航天飞机在B.处由椭圆轨道进入空间站圆轨道时必须点火加速
根据题中条件可以算出月球半径
根据题中条件可以算出空间站质量
我国未来将建立月球基地并在绕月轨道上建立空间站如图所示关闭动力的航天飞机在月球引力的作用下沿椭圆轨道
图中航天飞机飞向
处的过程中,月球引力做正功 B.航天飞机在B.处由椭圆轨道可直接进入空间站轨道
根据题中条件可算出月球的质量
根据题中条件可算出空间站所受月球引力的大小
我国未来将在月球地面上建立月球基地并在绕月轨道上建造空间站.如图所示关闭发动机的航天飞机
在月球引力作用下沿椭圆轨道向月球靠近,并将在椭圆轨道的近月点
处与空间站
对接.已知空间站绕月圆轨道的半径为r,周期为T.,万有引力常量为G.,月球的半径为R..下列说法中错误的是( )
A.航天飞机在图示位置正在加速向B.运动 B.月球的第一宇宙速度为v=
C.月球的质量为M=
要使航天飞机和空间站对接成功,飞机在接近B.点时必须减速
2010年10月1日我国成功发射嫦娥二号探月卫星不久的将来我国将建立月球基地并在绕月轨道上建造空间站
图中航天飞机由A到B的过程速度越来越小
航天飞机在B处由椭圆轨道进入空间站圆轨道时必须点火加速
根据题中条件可以算出月球半径
根据题中条件可以算出空间站质量
我国未来将建立月球基地并在绕月轨道上建造空间站.如图所示关闭动力的航天飞机在月球引力作用下向月球靠近
图中航天飞机正加速飞向
处 B.航天飞机在B.处由椭圆轨道进入空间站轨道必须点火减速
根据题中条件可以算出月球的密度
根据题中条件可以算出空间站受到月球的万有引力
我国未来将建立月球基地并在绕月轨道上建立空间站如图所示关闭动力的航天飞机在月球引力作用正向月球靠近并
图中航天飞机正加速飞向
处 B.航天飞机在B.处由椭圆轨道,进入空间站轨道必须点火减速
根据题中条件可以算出月球质量
根据题中条件可以算出空间站受到月球引力大小
2015年·宁夏2市模拟4月我国未来将建立月球基地并在绕月轨道上建造空间站.如图所示关闭发动机的航天
航天飞机到达B处由椭圆轨道进入空间站轨道时必须加速
航天飞机正在由A处加速飞向B处
月球的质量为M=
月球的第一宇宙速度为v=
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DavidBowieoneoftheworldsmostinfluentialmusicalartistshaspassedawayattheageof69fromcancer.Peoplearoundtheworldaremourningthe1dieofamanwhowasarockstarapopstaranactorandsomeonemanypeoplewouldconsider2all﹣aroundcreativegenius天オ. Duringhislifetime.Bowiesrecordsalesestimatedat140millionalbumsworldwide3makehimoneoftheworldsbest﹣sellingmusicartists.Bowiepushedthe4boundaryofallartformshetouchedsingingmoviesfashionandsongwriting.Heappliedhisknowledge5hisworksothathissongswerealwaysfaraheadof6othersweredoingatthetime.7contributetoBowiesoftenoddlookwasthefactthathiseyeswere8usualandinteresting.In1962whenhewasyoungaboyhithimintheschoolyardandthepupil瞳孔ofhislefteyebecame9permanentdamaged.HislastmusicvideoLazaruswhichwasreleasedinearly. Januarywasintendedtobeatypeofmusicaland10artgoodbyeforhisfans.
Peoplearesooccupiedthesedaysthatmanyhavenotimetocook1.Actuallymostfamilieslovehomecooking!Thefoodtastesgoodandwarmandafamilymealbringseveryonetogether. Anotherreasonpeopleenjoyhomecookingisthatitisoftenawayofshowinglove.Aparentwhobakesabagofchocolatecookiesisn'tjustsatisfyingachild'ssweettooth.2.ThemessagesaysIcareaboutyouenoughtospendseveralhoursmakingcookiesthatyouwilleatupin15minutesifIletyou! Thereisalsosomethingaboutthesmellofgoodcookingthatappealstoallages.3itmakesusfeelsafeandloved.Nexttimeyousmellacakebaking.stopforamomentandpayattentiontoyourmood.Chancesarethegoodsmellismakingyoufeelhappy. Realestate房地产agentsknowthatgoodcookingsmellsareimportant.4theysometimesadvisepeoplewhosehomesareforsaletobakecookiesorbread.Thegoodsmellsmaketheplacefeellikehome.Thesepleasantsmellshelpconvincepotentialbuyersthatthehousewouldmakeagoodhomefortheirfamilytoo! Home﹣cookedmealscanalsobenefittheenvironment.Homecookinggivesustheopportunitytochooserawmaterialsoverprocessedmealswhichcutsdownonpackaging.5.You'llmakeanevenbiggereffectontheenvironmentbyreducingtheamountoftransportationrequiredtogetfoodtoyourplate. A.Thiscreatesaproblem B.Iftheyaretoobusytocook C.Heorsheissendingamessage D.Evenifwearetheonesdoingthecooking E.Ifpossiblebuyersarecomingtoseethehouse F.Getreadytomakemealsforyourfamilymembers G.Buythosematerialsfromlocalfarmersorgrowonyourown
WhistlerWorldskiSnowboardFestival TherearemanyreasonswhytheWorldSki&SnowboardFestivalhasbeensopopularforthepast22years.KnowntolocalsasWSSFthefestivalcombinesspringenergywithWhistlersuniquemountainculture.Itisbeingheldfrom10thAprilto15thAprilattheWhistlerConferenceCentreinWhistler.Canada.Therearephotographyfilmmakingskiandsnowboardcompetitions. WSSFSchedule Belowaresomeoftheevents. TuesdayApril10 Eightfamousadventurersgivevisualstoriestotheaudience.TheeightpeopleincludemountainbikersDarrenBerreclothandHansReyclimberJohnLongdiverJillHeinerthsnowboarderAlexWarburtonskierJohnnyThrashandadventurersCaseyBrownandTedBaird. WednesdayApril11 Thisfreeexhibitgivesyouadeeperlookatmountainculture.Itgoesfurtherthansimplylandscapesandwildlife.TheexhibitwillbeopentoeveryonefromApril1ltoApril13. Teamshave72hourstoshooteditandproduceashortfilmtakenwithin100kilometresofWhistlerVillage.JudgeswillchoosejustonewinnerforBestofshow. ThursdayApril12 Sixphotographerscompetetoamazethejudgesandtheaudiencewithpicturesthatrecordsportscultureandthehumanspirit. FridayApril13 WhistlerBlackcombisthefourthstopinBritishColumbiaCanadaforthissnowboardcontest.ThecontestisfreetoenterandthetwochampionsmanandwomanwillshareC﹩50000. SaturdayApril14 Competitorsincludeamixofracinglegends.Theaudiencecanviewtheskiraceforfree.TheskiracedependsontheweatherandisscheduledforSaturdayApril14butmaybemovedtoFridayApril13﹣checkwssf.comforup﹣to﹣dateinformation. 1WhatcanwelearnabouttheWorldSkiSnowboardFestival? A.Itisaseven﹣dayfestival B.ItisheldinAprileveryyear. C.Ithasahistoryofovertwentyyears. D.Itisbestknownforwhistlersmountainculture. 2WhatcanvisitorsdoduringtheWorldSkiSnowboardFestival? A.EnjoyfilmsmadebycompetitorsonApril11. B.SeeeightfamousmountainbikersonApril10. C.WatchaskiracethatwilldefinitelyhappenonSaturday. D.ViewanexhibitfeaturingmountaincultureonApril12. 3Whichoftheeventsmentionedinthetextoffersaprize? A.Theskirace. B.Thesnowboardcontest. C.Thephotographycompetition. D.Thefilmmakingcompetition.
假设你是李华你的加拿大朋友David将于七月份参加一个中学生汉语演讲比赛现急于想提高自己的普通话水平.请根据以下要点给David回一封电子邮件 1.询问David的生活和学习情况 2.就如何提高普通话提两点建议. 注意1词数100左右 2.可适当增加细节以使行文连贯 3.文章中不得出现真实学校名称和考生姓名. DearDavid ﹣﹣﹣﹣﹣﹣﹣﹣﹣﹣﹣﹣﹣ Yours LiHua
It's27yearssincemylastconversationwithmymotherwhodidn'tfinishschoollikemanyofhercontemporarygirls.SheoftentoldmeInevergotmy1butonedayyouwill. Pointingtoatreeorcowsheaskedmeto2theirEnglishnamesafterher.Feeling3IaskedMamaWhydoIhavetolearnthese4phrases?Sheheldherpenrightbeforemyeyes.Holditfirmlyshe5me.forthispenandthenewforeignlanguagewillbeyourcompassto6aroundtheworld.SadlymymotherdiedofbreastcancerwhenIwassix. TurningsevenItraveled30milestoliveclosertomyschool.Butcloserisa7terminUgandawhich8Ihadtogetupasthe9sunroseandthenran8.8milesbarefoottoschool.AlsoIneededtocarryastickto10snakesanddogs.Duringthe11seasonthepathtoschoolwas12dailyandI'dswimwithonehandusingtheotherhandto13thebookbagonmyhead. Researchshows70percentofpoorchildrendon't14primaryschoolinUganda.Reasonsforthis15dropoutrateincludesthelong16somechildrenmust17amongmanyotherreasons. FortunatelyI'vemadeit.WheneverIseethesunriseIam18ofthewisdomofmymotherwho19metodreambigandtousethe20ofthepentomakemydreamcometrue. 1A.degree B.scholarship C.recommendation D.admission 2A.recite B.use C.repeat D.guess 3A.anxious B.curious C.disappointed D.annoyed 4A.tough B.new C.foreign D.old 5A.encouraged B.consulted C.blamed D.frightened 6A.look B.turn C.walk D.sail 7A.relative B.real C.simple D.technical 8A.proves B.means C.states D.argues 9A.warm B.early C.bright D.hot 10A.seekfor B.makeuseof C.lookafter D.lookoutfor 11A.summer B.cold C.rainy D.dry 12A.damaged B.repaired C.blocked D.flooded 13A.drag B.hold C.put D.seize 14A.attend B.enter C.complete D.continue 15A.constant B.steady C.low D.high 16A.distances B.periods C.lists D.stories 17A.cover B.consider C.judge D.measure 18A.informed B.warned C.reminded D.inquired 19A.enabled B.inspired C.commanded D.trained 20A.value B.power C.symbol D.length
如图所示一长木板静止在水平地面上一可视为质点的滑块放在长木板的左端长木板和滑块的质量均为m长木板和滑块间的动摩擦因数为μ长木板与水平地面间的动摩擦因数为μ重力加速度为g最大静摩擦力等于滑动摩擦力.现给滑块一水平向右的初速度v0要使滑块刚好滑到长木板的最右端求 1长木板的长度L 2滑块运动的时间t.
如图所示三个等量的点电荷固定在正三角形的三个顶点上AC两点为正电荷B点为负电荷D为AC中点.下列说法正确的是
Laughterispartoftheuniversalhumanvocabulary.Allmembersofthehumanspeciesunderstandit.UnlikeEnglishorFrenchorSwahiliwedon'thavetolearntospeakit.Werebornwiththecapacitytolaugh. Verylittleisknownaboutthespecificbrainmechanismsresponsibleforlaughter.Contrarytofolkwisdommostlaughterisnotabouthumoritisaboutrelationships.TofindoutwhenandwhypeoplelaughIwentwithseveralassistantstolocalmallsandrecordedwhathappenedjustbeforepeoplelaughed.Overa10﹣yearperiodwestudiedover2000casesofnaturallyoccurringlaughter. Wefoundthatmostlaughterdoesnotnecessarilyfollowjokes.PeoplemaylaughafteravarietyofstatementssuchasHerecomesMaryHowdidyoudoonthetest?orDoyouhavearubberband?Thesecertainlyaren'tjokes. Webelievelaughterevolvedfromthepanting喘气的behaviorofourancientancestors.Todayifwetickle使发痒chimpstheydon'tlaugh.Butinsteadtheyproduceapantingsound.That'sthesoundofapelaughterandit'stherootofhumanlaughter. Apeslaughinthekindsofsituationsthatleadtohumanlaughterlikegamesthatinvolvechasing.Otheranimalsproducesoundsduringplaybuttheyaresodifferentfromlaughter.Ratsforexampleproducehighsoundsduringplayandwhentickledbuttheseareverydifferentinsoundfromhumanlaughter. Laughterisoftenpositivebutitcanbenegativetoo.There'sadifferencebetweenlaughingwithandlaughingat.Peoplewholaughatothersmaybetryingtodrivethemoutofthegroup. Noonehasactuallycountedhowmuchpeopleofdifferentageslaughbutyoungchildrenprobablylaughthemost.Atages5and6weprobablylaughmorethanatanyothertimes.Adultslaughlessthanchildrenprobablybecausetheyplayless. Worknowunderwaywilltellusmoreaboutthebrainmechanismsbehindlaughterhowithasevolvedandwhywe'resosusceptibletotickling. 1Whatwasthepurposeofthedecade'sresearch? A.Toprovethatpeoplelaughbecauseofhumour. B.Tofindouttherealreasonforpeopleslaughter. C.Toresearchpeoplesdifferentreactiononjokes. D.Torecordconversationsamongshoppersinmalls. 2Whatcanwelearnfromthetext? A.Peoplewhoplaymoretendtolaughmore. B.Apesproducehighsoundswhentickled. C.Scientistsknowthebrainmechanismsresponsibleforlaughterwell. D.Thesituationsinwhichapeslaughareverydifferentfromthoseinwhichhumanslaugh. 3Whatdoestheunderlinedwordsusceptibleinthelastparagraphprobablymean? A.Sensitive. B.Flexible. C.Addictive. D.Reliable. 4Whichofthefollowingmightbethebesttitleforthetext? A.TheImpactofLaughter B.TheMeaningofLaughter C.ABigMysteryWhyDoWeLaugh? D.LaughterTheMostBeautifulWords
Somepigstendtobeoptimisticwhileothersarepessimisticaccordingtoanewresearchthatismeaningfultoanimalwelfare.ThestudypublishedinthejournalBiologyLettersisthefirsttoshowthatmoodandpersonalityinteractinananimalinfluencingjudgment. AsheraresearcherattheUniversityofNewcastle'sInstituteofNeuroscienceandherteamhousedgroupsofpigsintwotypesofenvironment.Onereflectedstandardcommercialconditionsandtheotherwascushierwithmorespaceandplentyofsoftdeepstraw.Afterthepigsgotaccustomedtothesenewhomesoverafewweekstheresearcherspicked18pigsfromeachtypetotrainandtesttheirjudgment. Todothiswetrainedeachpig.Inonecornerofatrainingroomtherewouldbeabowlwithchocolatesweets﹣pigslovethem﹣andattheoppositesideoftheroomtherewouldbeabowlcontainingcoffeebeanswhichpigsfindbitter﹣tastingaresearchersaid. Overanumberoftrainingtrialspigslearnedtogotothebowlreliablywhenitwasinthecornerwheretheyhadfiguredouttoexpectchocolatesweets.Onthecontrarytheyquicklylearnedtoavoidthebowlwhenitwasinthecornerwheretheywouldexpecttofindthecoffeebeans. Theresearchersnextplacedanunfamiliarbowlindifferentlocationstoseehowthepigswouldreact.Somehappilydashedtothebowlnomatterwhatwasinsideshowingoptimismthatitwouldcontaintheirfavoritesweets.Othershoweverbehavedasthoughtheyexpectedittocontaincoffeebeansdisplayingpessimism. Thefindingssuggestthataone﹣size﹣fits﹣allanswertoanimalwelfareissuesdoesnotexist.Evenifpigsarejustequaltobaconorothermeatforsomepeoplethereisstillcauseforconcern.Studieshavesuggestedthathowananimalistreatedduringitslifetimecandirectlyaffectmeatqualityandtaste. 1Whatwasthestudytryingtofigureout? A.Howtomakepigshappier. B.Thesimilaritiesbetweenhumansandpigs. C.Howlivingenvironmentaffectedpigs'mood. D.Howpigs'moodandpersonalityaffectedtheirjudgment. 2WhatdoestheunderlinedwordcushierinParagraph2mean? A.Simple. B.Morecomfortable. C.Unpractical. D.Lessfree. 3Whichbowlcouldtestwhetherapigwasoptimisticorpessimistic? A.Thebowlwithchocolatesweets. B.Thebowlunfamiliartotwotypesofpigs. C.Thebowlfullofbothsweetsandbeans. D.Thebowlcontainingcoffeebeans. 4Whatdothefindingsofthenewresearchimply? A.Peopleshouldtreatpigsequally. B.People'shealthreliesonmeatquality. C.Peopleshouldmeetpigs'variousneeds. D.People'sattitudetowardpigsistotallywrong.
如图所示光滑的水平面上有PQ两个竖直固定挡板AB是两档板连线的三等分点.A点处有一质量为m2的静止小球紧贴P挡板的右侧有一质量为m1的等大小球以速度v0向右运动并与m2相碰.小球与小球小球与挡板间的碰撞均为弹性正碰两小球均可视为质点.求 1两小球m1和m2第一次碰后的速度v1和v2 2若两小球之间的第二次碰撞恰好发生在B点且m1<m2求m1和m2的可能比值.
1905年爱因斯坦提出光子假设成功地解释了光电效应因此获得1921年诺贝尔物理学奖.下列关于光电效应的描述正确的是
氘核和氚核发生核反应的方程为H+H→He+X则粒子X是
ThereisalargepercentageofAsianpeopleintheUS.They'rehard﹣workingrespectfulbutstrangesometimes.1Asianpeoplearedifferentfrompeopleinanyothercultures.Ifyouthinkyouknowthemyoumightwanttothinkagain. Howaretheydifferent?WhenitcomestomostAsianculturerespectiseverything.2Ifyoudon'tshowproperrespectforhimyouwillgetsomerealconsequencesafterwardandespeciallyifhe'syourboss.It'ssomethingcalledfacesavingintheAsianculture.It'sridiculoussometimesbutit'stheirculture.Sometimestheirculturecancomeinbetweentheirrelationshipatwork.Asianpeoplemightexpectalotofrespectfromtheirco﹣workerswhentheirco﹣workersjustseethemasanequal. 3Ifyou'reAsianyoumightwanttounderstandtheAmericancultureandevenadapttotheircultureifyouworkwiththem.Itwillbeeasierforyousinceyoureintheircountries.ImagineanAmericaworkinginChinaexpectingChineseco﹣workerstogetalongwithhimwhenhecriticizesthemstraightoutoneverysinglematterinfrontofeveryoneIthinktheywilltakehimoutsideandtakecareofhim.4 Ifyou'reanAmericanbossgivingyourAsianemployeeareviewyouwillseethattheywillhaveaproblemwithyournegativeremarks.Theywillthinkthatyoudon'tlikethemdisrespectfulandwanttogetridofthem.5Ofcourseit'snotfairforyouasanAmericanbossbutjustexpectthatitcanbesomethingthatisonyourAsianemployee'smind. A.Infactyourejustdoingyourjob. B.Soyouhavenochoicebuttotrustthem. C.AmericanscannotgetalongwellwithAsians. D.Itjustdoesn'tworkthatwaywithAsianpeople. E.AmericansareverydifferentfromAsianpeople. F.YoucandoanythingyouwantbutdontdisrespectanAsianman. G.Ifyoudon'tunderstandtheircultureyouwillgetsomeproblemswiththem.
设F1F2分别是椭圆的左右焦点. Ⅰ若P是该椭圆上的一个动点求的最大值和最小值 Ⅱ是否存在过点A50的直线l与椭圆交于不同的两点CD使得|F2C|=|F2D|若存在求直线l的方程若不存在请说明理由.
2018年11月1日23时57分我国在西昌卫星发射中心用“长征三号乙”运载火箭成功发射第四十一颗北斗导航卫星.这是我国“北斗三号”系统第十七颗组网卫星也是“北斗三号”系统首颗地球同步轨道卫星.质量为m的卫星发射过程要经过多次变轨方可到达预定轨道如图所示先将卫星发射至近地圆轨道I然后在A点近地点点火加速卫星做离心运动进入椭圆轨道Ⅱ在B点远地点再次点火加速进入圆形轨道Ⅲ.已知卫星在轨道I和轨道Ⅲ上做匀速圆周运动的轨道半径分别为R1和R2速率分别为v1和v2地球的质量为M引力常量为G则卫星在轨道Ⅱ上运动时下列说法正确的是
ForseveralmonthsCarahasbeenworkingupthecouragetoapproachhermomaboutwhatshesawonInstagram.Notlongagothe11﹣year﹣oldgirllikealltheotherkidsinthisstorydiscoveredthathermomhadbeenpostingherphotosformuchofherlife.I'vewantedtobringit.It'sstrangetoseemyselfupthereandsometimestherearepicturesIdon'tlikeofmyselfshesaid. LikemostothermodernkidsCaragrewupimmersedinsocialmedia.Whilemanykidsmaynotyethaveaccountsthemselvestheirparentsschoolssportsteamsandorganizationshavebeenorganizinganonlinepresenceforthemsincebirth.Theshockofrealizingthatdetailsaboutyourlifehavebeensharedonlinewithoutyourpermissionorknowledgehasbecomeanimportantexperienceinthelivesofmanyteenagers.Recentlyaparentingblogger博主wroteinaWashingtonPostessaythatdespite不顾her14﹣year﹣olddaughter'shorroratdiscoveringthathermotherhadsharedyearsofhighlypersonalstoriesandinformationaboutheronlineshesimplycouldnotstoppostingonherblogandsocialmedia.ThewritersaidthatpromisingherdaughterthatshewouldstoppostingaboutherpubliclyontheInternetwouldmeanshuttingdownavitalpartofmyselfwhichisn'tnecessarilygoodformeorher.averageparentsdothesame.There'sevenaspecialwordforitsharenting. AlmostaquarterofchildrenbegintheirdigitalliveswhenparentsuploadtheirphotostotheInternetaccordingtoastudyconductedbytheInternet﹣securityfirmAVG.Thestudyalsofoundthat92percentofkidsundertheageof2alreadyhavetheirownuniquedigitalidentity. 1HowdoesCarafeelabouthermom'sbehavior? A.It'saggressive. B.It'sappropriate. C.It'sannoying. D.It'sfavorable. 2Whydidtheparentingbloggerpostaboutherdaughteronline? A.Becauseitfilledupherblog. B.Becauseitshowedoffhersuccess. C.Becauseitrecordedherstories. D.Becauseitmeantalottoher. 3Whoarefondofsharenting? A.Aquarterofstudents. B.Mostordinaryparents. C.Kidsundertheageof2. D.Somecrazybloggers. 4Whichofthefollowingcanbethebesttitleforthetext? A.Children'sNewTrouble B.SocialMedia C.Kids'OnlinePeformance D.MommyBloggers
如图所示质量相同的小球AB通过质量不计的细杆相连接紧靠竖童墙壁放置.由于轻微扰动小球AB分别沿水平地面和竖直墙面滑动滑动过程中小球和杆始终在同一竖直平面内当细杆与水平方向成30°角时小球A的速度大小为v重力加速度为g忽略一切摩擦和阻力则细杆的长度为
TheFiveBestCountriestoMovetoForRetirement Retiringinadifferentcountryisgainingpopularity.Belowarefiveofthebestcountriestoseekretirement. CostaRica MildclimatebreathtakinglandscapesandbeachesdrawretireCostaRica.ThecountryreadilywelcomesimmigrantsandoffersasimpleresidencyFEprocess.Withamonthlyincomeofatleast﹩1000permonthfromSocialSecurityorasimilarsourcepeopleenjoyahighstandardoflivingatamuchlowercostthantheU.S.. Malaysia RetireeswhochoosetomakeMalaysiahomewillappreciateitsrichcultureandattractivescenery.Moreoverthecountryoffersmodernfacilitiesatmodestprices.Immigrantsenjoyconvenienceandcomfortintheirdailylife.Youwillfindlow﹣costrentalunits.deliciousstreetfoodandvariousshoppingmalls. Mexico BecauseitsclosetotheU.S.MexicodrawsmorethanamillionAmericanretireestoitsborders.IncreasingimmigrantcommunitiesenjoyseasidelivingandconversationswithfriendlyEnglish﹣speakinglocals.Pluslegalresidentsovertheageof60receiveairlinegroceryandrestaurantdiscounts. Panama Gentleoceanwindtakestheheatoutofhotyear﹣roundtemperatureswhichhasbeenthechiefattractiontoforeignretirees.BeautifulbeachesandaboomingeconomyalsoattractretireestoPanama.AnincomeofS2000permonthcoversmodestlivingcostsFurthermorethecountryoffersdiscountstoretireeswithaspecialvisa. Ecuador Lazycoastaltownssun﹣shininghotspotsandnature﹣filledviewswaitforimmigrantsseekingacarefreelifestyle.PublictransportationcostsinEcuadormakeowningavehicleunnecessary.Abusrideonlycosts25centsandtaxirideswillrunabout﹩3. 1WhatdoCostaRicaandMalaysiahaveincommon? A.Convenientshopping. B.Relativelylowlivingcost CVariousculturalactivities D.Simpleimmigrationprocedures. 2Whichcountry'slocationspeciallyattractsretireesfromtheU.S.? A.Malaysias B.Mexico's C.Panama's D.Ecuador's 3WhatisthemainreasonforretireestochoosePanama? ABeautifulbeaches BAboomingeconomy C.Discountsforretire D.Pleasantclimate
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