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如图，光滑的平行金属导轨水平放置，电阻不计，导轨间距为L，电阻R1、R2并联后接在导轨左端．整个区域内存在垂直轨道平面向下的匀强磁场．一质量为m，电阻为r的金属棒MN置于导轨上，与导轨垂直且接触良好...
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高三下学期物理《》真题及答案
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如图在一磁感应强度B.=0.5T的匀强磁场中垂直于磁场方向水平放置着两根平行金属导轨导轨的电阻不计.
如图a所示水平放置的光滑的两根平行金属导轨间距L.=0.3m导轨左端连接R.＝0.6Ω的电阻区域ab
如图所示abcd为水平放置的平行形光滑金属导轨间距为l导轨间有垂直于导轨平面的匀强磁场磁感应强度大小
电路中感应电动势的大小为
电路中感应电流的大小为
金属杆所受安培力的大小为
的发热功率为
两根平行光滑金属导轨MN和PQ水平放置其间距为0.60m磁感应强度为0.50T的匀强磁场垂直轨道平面
如图在一磁感应强度B.=0.5T的匀强磁场中垂直于磁场方向水平放置着两根平行金属导轨导轨的电阻不计.
如图所示间距为L.的光滑平行金属导轨水平放置导轨上有一电阻为r的金属棒ab与导轨接触良好导轨一端连接
金属棒a端电势比b端高
电阻R.两端的电压为BLv
ab棒受到的安培力的方向向左
外力F.做的功等于电阻R.上发出的焦耳热
如图所示两根平行光滑金属导轨PQ和MN间距为d它们与水平面间的夹角为α上端与阻值为R的电阻连接导轨上
如图所示间距为d的光滑平行金属导轨水平放置在竖直向上的磁应强度为B的磁场中一端接有阻值为R的电阻一质
如图A－7所示水平放置的光滑的金属导轨MN平行地置于匀强磁场中导轨宽为d磁场的磁感应强度为B方向与导
如图水平放置的光滑的金属导轨M.N.平行地置于匀强磁场中间距为d磁场的磁感强度大小为B.方向与导轨平
如图所示efgh为水平放置的足够长的平行光滑导轨导轨间距为L.=1m导轨左端连接一个R.=2Ω的电阻
8分如图所示平行光滑导轨MN和M′N′置于水平面内导轨间距为l电阻可以忽略不计导轨的左端通过电阻忽略
如图A－7所示水平放置的光滑的金属导轨MN平行地置于匀强磁场中导轨宽为d磁场的磁感应强度为B其方向与
10分两根平行光滑金属导轨MN和PQ水平放置其间距为d=0.6m磁感应强度为B.=0.5T的匀强磁场
如图所示在方向竖直向上的磁感应强度为B的匀强磁场中有两条光滑固定的平行金属导轨MNPQ导轨足够长间距
如图水平放置的光滑的金属导轨M.N.平行地置于匀强磁场中间距为d磁场的磁感强度大小为B.方向与导轨平
如图所示水平放置的光滑的金属导轨M.N.平行地置于匀强磁场中间距为L.金属棒ab的质量为m电阻为r放
如图所示电阻不计间距为l的光滑平行金属导轨水平放置于磁感应强度为B方向竖直向下的匀强磁场中导轨左端
A
B
C
D
如图18所示efgh为水平放置的足够长的平行光滑导轨导轨间距为L.=1m导轨左端连接一个R.=2Ω的
如图所示间距为L电阻不计的足够长平行光滑金属导轨水平放置导轨左端用一阻值为R的电阻连接导轨上横跨一
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如图为测量某山峰的高度即OP的长选择与O在同一水平面上的AB为观测点．在A处测得山顶P的仰角为45°在B处测得山顶P的仰角为60°．若AB＝30米∠AOB＝30°则山峰的高为米．
△ABC的内角ABC的对边分别为abc根据下列条件解三角形其中有两解的是
设{an}是公比为正数的等比数列若a1＝2且2a2a38成等差数列． 1求{an}的通项公式 2设求证数列{bn}的前n项和Tn＜1．
Whenwasthelasttimeyoutoldsomeonetheyinspireyoutogotoworkeachmorning? TeachersatOakParkHighSchoolinKansasCityMissourididjustthatthisSeptemberwhentheypulledindividualstudentsoutofclasstotellthemjusthowmuchtheyappreciatedthem. Thestudents'reactionswhichwerecaptured捕捉onvideoandsharedonYouTubeinanow﹣viralvideorangedfromshythankstohugsandtears. Ihavebeenchallengedtofindastudentwhomakesmewanttocometoschooleverydaysaysoneteacherinthevideoandthat'syou. JamieMcSparinateacherinchargeoftheschool'sacademyprogramforat﹣risksophomores二年级学生andjuniorsposedthechallengewritesABCNews. InitiallywhenwepulledthekidsouttheyallthoughttheywereintroubleMcSparintoldABCNews.Anyteacher﹣studentinteractionalwaysseemstobenegative消极的andthatwassomethingthatbotheredmetoo.Nomatterifthey'reagoodkidoratroublemakeroranythingtheyalwaysthoughttheywereintroubleshesays. McSparinsaysshegottheideafortheprojectafterattendingaprofessionaldevelopmentworkshopthissummercalledthepowerofpositivity. IliketheideaoflettingstudentsknowtheyareappreciatedbecausewedoappreciatethemIjustdon'tthinkwesayitenoughshetoldlocalnewsoutletWDAF﹣TV. It'ssafetosaythechallengewaseffective. Ifeelspecialsaidoneoftheboysinthevideo.Youshouldsaidhisteacher.Youarespecial. 1WhatdoestheunderlinedwordposedinParagraph5mean? A.Presented. B.Rejected. C.Ignored. D.Evaluated. 2Howdidthestudentsprobablyfeelwhenpulledoutoftheclassroomatfirst? A.Nervous. B.Thrilled. C.Curious. D.Encouraged. 3WhatinspiredMcSparintochallengetheproject? A.Thetroublecausedbystudents. B.Theneedofshootingthevideo. C.Aseminarnamedthepowerofpositivity. D.Aprogramrelatedtostudents'interactions. 4Whatmessagedoesthistextmainlyconvey? A.Challengeisunavoidableinlife. B.Everyoneneedstobeappreciated. C.Positivityoutweighsnegativity. D.Newsmediacontributetostudents'progress.
椭圆点＝1的离心率为
Humansmakemistakes.Evensurgeonswithyearsofexperiencearenotinfallible.Butwhatifthesedoctorscouldpooltheirknowledgeandexperiencetogetherandcreateasurgicalstandardofcaretobecarriedoutbymachines? That'stheideabehindsurgicalrobotswhichmaysoonperformmostsurgeriesfromsewinguptinywoundstoperformingheartprocedures.Manyoftheseoperationsareinfactalreadycompletedwiththeassistanceofrobots.Butarecenttestsuggeststhatrobotsintheoperatingroommaysoongoastepfurtherperformingonsofttissuecompletelyontheirownfromstarttofinish. TheSmartTissueAutonomousRobotSTARsuccessfullycompletedsurgeriesonpigs.We'rethefirstgrouptodevelopautonomousroboticsurgerywithsoft﹣tissuesurgeryandwhencomparedtostandardoperationit'sbettersaysPeterKimprofessorofsurgery.Theideaisnottoreplacesurgeonsitwillmakethesurgeonsbetterandmaketheproceduressafer. ArecentMayoClinicstudyfoundthatmajorsurgicalerrors﹣includingoperatingonthewrongsiteorsideofthebodyorevenleavingtoolsorobjectsinsidethepatient﹣occureveryoneoutof22000procedures.That'srarebutrobotslikeSTARwouldaimtolowerthenumberevenfurther. InthedaVincisurgicalsystemsurgeonsplacetheirarmsinsideinstrumentsandusetheirhandstocontrolthemovementofrobotictoolsontheoperatingtablefromafar.Therobot'severymajormoveiscontrolledbysurgeonsandthusitsresultsmayvarybasedonthesurgeon'strainingorexperience. STARontheotherhandisentirelyautonomous.It'snotonlyabletoworkonitsownandperformsurgerieswithamoreflexiblehandbutit'sabletoreacttotheunexpectedincidents.Cuttingintohardtissuelikebonesisonethingbutoperatingonmovingsofttissueisfarmorecomplex.STARreactstoachangingenvironmentsimilartohowself﹣drivingcarsareprogrammedtonotonlydriveonthehighwaybutalsoreacttoanotherdrivermakingamistakeandgettinginyourway. 1TheunderlinedwordinfallibleinParagraph1probablymeans. A.quitesmart B.reallycreative C.ratherresponsible D.alwaysright 2WecanlearnfromthepassagethatSTAR. A.canperformtheoperationonitsown B.hasbeenwidelyusedintheoperatingroom C.canmakesurgeriesmuchfaster D.willtaketheplaceofsurgeons 3InthedaVincisurgicalsystem. A.robotsaretrainedfromafar B.robotsalwaysmakemistakes C.surgeryresultsdependonsurgeons D.surgeonshavetroublecontrollingrobots 4Inthelastparagraphtheauthormentionsself﹣drivingcarsinordertoshow. A.howsmartanautonomousrobotcanbe B.howdifficultself﹣drivingonthehighwayis C.howbadgettinginanotherdriver'swaymightbe D.howdangerousoperatingonpeopleis.
如图已知四棱锥P﹣ABCD底面ABCD为边长为2对的菱形PA⊥平面ABCD∠ABC＝60°EF分别是BCPC的中点． 1判定AE与PD是否垂直并说明理由 2若PA＝2求二面角E﹣AF﹣C的余弦值．
若等比数列{an}的前n项和为Sn2a3+a6＝0则＝
30分Itwasmyfirstyearofgraduateschoolandmyprofessorwasstandingontheplatform.Hewastellingusabouta1hemadeyearsago. Aboutadecadeearliermyprofessorhadbeenasalesmanageratalargecompany.Theywere2anationalcampaignandpreparingforamajorbrandlaunch.Myprofessorwas3theoperation. Foralmosttwomonthsbeforethelaunchdayhewas4alloverthecountrytotalkwithmajorpartners.5crossingthecountryonflightshewasalsotryingto6hisdepartment.Forweekshewouldhavemeetingsalldayanswer7andphonecallsallnightand8threeorfourhoursofsleep. Theweekbeforethebiglaunchdayhisbody9.Hehadtoberushedtothehospital.Majororganshadstartedto10fromthelong﹣termstress.Hespentthenexteightdaysinhospital11todoanythingasthelaunchdaycameandwent. Imaginethatyour12andenergyareabucketofwater.Inyourdailylifetherearethingsthat13yourbucketup.Theseareinputslikesleepnutritionlaughterandotherformsof14.Therearealsoforcesthatdrain使排出thewaterfromyourbucket.Theseare15likestressfromworkorschoolrelationshipproblemsorotherformsofanxiety. Theforcesthatdrainyourbucketaren'tall16.Toliveaproductivelifeitcanbeimportanttohavesomethings17outofyourbucket.Workinghardinthegymatschoolorattheofficeallowsyoutoproducesomething18.Butpositiveoutputsarestilloutputsandtheydrainyourenergy19.Theseoutputsaregradual.Evenalittleleakcanresultinsignificantwaterloss20time. 1A.prediction B.decision C.fortune D.mistake 2A.attheendof B.inthemiddleof C.atthemercyof D.onthewayto 3A.sponsoring B.leading C.assisting D.adopting 4A.researching B.driving C.flying D.inspecting 5A.Before B.Though C.While D.Since 6A.run B.promote C.expand D.observe 7A.emails B.charges C.problems D.doors 8A.pullin B.squeezein C.takein D.bringin 9A.giveup B.givein C.giveout D.giveaway 10A.disappear B.suffer C.function D.fail 11A.ready B.unwilling C.eager D.unable 12A.health B.status C.success D.reputation 13A.break B.pack C.fill D.cover 14A.rest B.recovery C.entertainment D.accommodation 15A.restrictions B.consequences C.examples D.outputs 16A.uncontrollable B.unpredictable C.uncomfortable D.unfavorable 17A.flowing B.slipping C.escaping D.growing 18A.typical B.valuable C.casual D.exotic 19A.suddenly B.surprisingly C.partly D.thoroughly 20A.over B.beyond C.after D.before
在△ABC中B＝M为AC边上的一点且BM＝2若BM为∠ABC的角平分线则﹣的取值范围为
已知椭圆的四个顶点围成的四边形的面积为原点到直线的距离为．1求椭圆C的方程2已知定点P02是否存在过P的直线l使l与椭圆C交于AB两点且以|AB|为直径的圆过椭圆C的左顶点若存在求出l的方程若不存在请说明理由．
已知F是抛物线x2＝4y的焦点AB是该抛物线上的两点|AF|+|BF|＝5则线段AB的中点到x轴的距离为．
10分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. InrecentyearstherehavebeenmoreandmoreConfuciusInstitutesbeingbuiltallovertheworldthatshowsourChineseculturehasbeenbecomemuchmorepopularthanever.AsoneoffourancientcivilizationsChinacreatesmanysplendidcultureswithinitslonghistory.TheancientChinesecultureoncehadgreatinfluencesintheworld'scivilizationespeciallyinJapanSouthKoreaandotherAsiancountry.TheChinesecultureisslowaccumulatedinthewholeChinesehistorymadeitcolorfulandbrilliant.IfonewanttoknoworstudyChineseculturemoredeeplyheorshemustspendmuchtime.Thereforeheorshecanonlygetthetipofaniceberg.
若M＝2a2﹣3a+5N＝a2﹣a+4则M与N的大小关系为
若xy满足约束条件则z＝2x﹣3y的最小值为．
设函数fx＝|x﹣1|﹣|x+1|． 1求不等式fx≥1的解集 2若fx＞a2﹣3a对x∈R恒成立求a的取值范围．
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已知过M34的直线l与抛物线Cy2＝16x交于点AB．1若M为弦AB的中点求直线l的方程2若F为抛物线C的焦点P为抛物线C上的动点求|PF|+|PM|的最小值．
若对任意的正数ab满足a+3b﹣1＝0则的最小值为
若a＞b则的最小值为．
设命题p∀x∈Nx∈Z则￢p为
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某市准备建一个如图所示的综合性休闲广场已知矩形广场的总面积为2000平方米其中阴影部分为通道通道的宽为1米中间的两个小矩形完全相同． 1用矩形的宽x米表示中间的三个矩形的总面积S平方米的函数关系式并给出定义域 2当矩形的宽为何值时S取得最大值并求出最大值．
Theskinundertheeyesisdelicatewhichiswhyitsometimesappearssunkenandhasdarkercoloringthanelsewhereontheface.Agingandhealthproblemsplayaroleinsunkeneyesbutotherfactorscancontributesoitmayaffectyoungerpeopleaswell. Dehydration Themostcommoncauseofsunkeneyesisdehydrationornothavingenoughwaterinthebody.Consumingtoomuchcoffeesodaandprepackageddrinksmayincreaseproductionofurine尿液whichmayleadtodehydration. Vitaminshortages ShortagesofvitaminCvitaminKandironcancauseeyestobecomesunken.VitaminChelpswithabsorbingironanddecreasingbruising瘀斑whilevitaminKisresponsibleforbloodthickeningcausingunhealthyskin.Easybruisingandunhealthyskinwillresultinsunkeneyes. Weightloss Mostpeopletendtoloseweightintheirfacefirst.Sometimestheweightlossissuddenenoughtomakebloodvessels血管belowtheeyeseasytoseeandtheskinclearproducingtheappearanceofsunkeneyes.Suddenweightlossmayalsocausenutritionalshortageswhichcanleadtosunkeneyes. Notenoughsleeporporqualitysleepcancausesunkeneyesandaperson'sDNAorthehabitofsmokingcanalsocontributetosunkeneyes.Mostcasesofsunkeneyesrelatetothequalityofanindividual'snutritionandhealthyliving.Whenthesecausesarecorrectedsunkeneyescanberesolvedwithoutfurthertreatment.Thismeansthatcausescanbeavoidedortreatedingoodtimetopreventtherecurrenceofsunkeneyes. 1Whatcanwedotopreventdehydrationaccordingtothetext? A.Refusecoffee. B.Drinkmorewater. C.Saynotosoftdrinks. D.Havecertaindrinksless. 2Whatwillleadtobruisingbelowtheeyes? A.LackofvitaminK. B.Watershortages. C.LackofvitaminC. D.Nutritionalshortages. 3Whichofthefollowingshouldbeavoidedforpeoplelosingweight? A.Palefaces. B.Suddenweightloss. C.Cleanskin. D.Narrowbloodvessels.
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8分Anxietyisanaturalresponsethatchangedgraduallyovermillionsofyearstomakeusmorecarefulandourbodiespreparedtofleedanger.Butfeelinganxiousbecauseyouheardanoiseonadarkstreetisn'tthesamethingashavingananxietydisorder.Thekeythingwelookforinthecliniciswhetheranxietyisinterfering妨碍withaperson'sday﹣to﹣daylifeorcausingthemalotofunhappinesssaysNickGreyofKing'sCollegeLondon. ToclinicalpsychologistslikeGreymaladaptive不恰当的beliefsaretypicalinanxietydisordersandareoftenusedtodeterminethetypeofanxietysomeonehas.Insocialanxietydisorderthemostcommonanxietydisorderyoumightbelievethatyourfaceturningredwillresultinpeoplelaughingatyou.Peoplewiththistypeofdisorderexperienceconstantandgreatfearbeforeduringandaftersocialevents. Ifyouhavepanicdisorderyoumightassumethatyouarehavingaheartattackifyourheartstartstorace.Thephysicalsymptomsofanxiety﹣apoundingheartdifficultybreathingfeelingdizzy﹣willthencomeoninarush.Everyonecanexperiencesuchpanicattacksfromtimetotimebutinpanicdisordertheattacksareregularandbecomeasourceofanxietythemselves. Othermaladaptivebeliefsarelessspecific.Generalizedanxietydisorderischaracterizedbycontinuousworriesaboutarangeofdifferenteventsoractivitiesforatleastsixmonths.Ifyouhavethisconditionthebeliefdrivingyouranxietycouldforexamplebethefeelingit'syourjobtotakecareofotherpeopleorthatyouhaveresponsibilitiesthatyoumustmeetatallcost.TodecidewhotoreferforfurthertreatmentdoctorsmightuseatoolcalledtheGAD7test. 1Whichofthefollowingbelongstoananxietydisorder? A.Quarrelingwithparents. B.Gettingtoschoolearlier. C.Missingalunch. D.Knockingonthewall. 2Whatissocialanxietycharacterizedby? A.Continuousworries. B.Pastexperiences. C.Maladaptivebeliefs. D.Frequentterrors. 3Whatwillhappentoyouwhenyouhavepanicdisorder? A.Youcan'tstandsteadily. B.Yourfaceturnsred. C.Youcan'ttouchanything. D.Yourhandsfeelnumb. 4Whatanxietydisorderoccursmoreoftenthanothers? A.Generalizedanxiety. B.Panicattacks. C.Socialanxiety. D.Acuteanxietyattacks.
“方程＝1表示的曲线为椭圆”是“2＜m＜6”的
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电路中感应电流的大小为
金属杆所受安培力的大小为
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