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在如图所示的竖直平面内，物体A和带正电的物体B用跨过定滑轮的绝缘轻绳连接，分别静止于倾角θ＝37°的光滑斜面上的M点和粗糙绝缘水平面上，轻绳与对应平面平行．劲度系数K＝5N/m的轻弹簧一端固定在0点...
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高三下学期物理《》真题及答案
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在如图所示的装置中两个光滑的定滑轮的半径很小表面粗糙的斜面固定在地面上斜面的倾角为θ＝30°用一根跨
如图所示拉B.物的轻绳与竖直方向成60°角O.为一定滑轮物体A.与B.间用跨过定滑轮的细绳相连且均保
如图所示一条细绳跨过定滑轮连接物体
B.，A.悬挂起来，
穿在一根竖直杆上，两物体均保持静止，不计绳与滑轮、B.与竖直杆间的摩擦，已知绳与竖直杆间的夹角为θ，则物体A.B.的质量之比m
A.
：m
B.
等于（ ）
A. cosθ：1B. 1：cosθ
tanθ：1
1：sinθ
在如图所示的装置中.表面粗糙的斜面固定在地面上.斜面的倾角为30°两个光滑的定滑轮的半径很小用一根跨
如图所示两物体AB的质量分别为M和m用跨过光滑定滑轮的轻绳相连A物体静止在水平面上.若不计摩擦A物体
在如图所示的装置中.表面粗糙的斜面固定在地面上.斜面的倾角为30°两个光滑的定滑轮的半径很小用一根跨
如图所示细绳B端固定其A端跨过固定在物体m上的定滑轮后用F=100N的恒力竖直向上拉使物体m沿斜面向
在如图所示的装置中.表面粗糙的斜面固定在地面上.斜面的倾角为=30°两个光滑的定滑轮的半径很小用一根
乙物体运动经过最高点时悬线的拉力大小为5N.
乙物体运动经过最低点时悬线的拉力大小为20N.
斜面对甲物体的最大静摩擦力的大小为l5N.
甲物体的质量为2.5 kg
如图所示跨过定滑轮的轻绳两端的物体A.和B.的质量分别为M.和m物体A.在水平面上且由静止释放当B.
如图所示用恒力F.通过光滑的定滑轮将静止于水平面上的物体从位置A.拉到位置B.物体可视为质点定滑轮距
14分在如图所示的装置中两个光滑的定滑轮的半径很小表面粗糙的斜面固定在地面上斜面的倾角为θ＝30°用
如图所示重力为500N的人使用跨过定滑轮轻绳拉重为200N的物体当绳与水平面成60°角时物体静止.不
如图7所示O为一定滑轮物体A与B间用跨过定滑轮的细绳相连且均保持静止拉物体B的轻绳与竖直方向成60°
在如图所示的装置中两个光滑的定滑轮的半径很小表面粗糙的斜面固定在地面上斜面的倾角为用一根跨过定滑轮的
如图所示跨过定滑轮的轻绳两端的物体A.和B.的质量分别为M.和m物体A.在水平面上且由静止释放当B.
在如图所示的装置中两个光滑的定滑轮的半径很小表面粗糙的斜面固定在地面上斜面的倾角为θ＝30°用一根跨
如图所示两物体A.B.的质量分别为M.和m用跨过光滑定滑轮的轻绳相连A.物体静止在水平面上.若不计摩
如图所示重力为500N的人使用跨过定滑轮轻绳拉重为200N的物体当绳与水平面成60°角时物体静止.不
如图所示一条细绳跨过定滑轮连接物体
B.，A.悬挂起来，
穿在一根竖直杆上，两物体均保持静止，不计绳与滑轮、B.与竖直杆间的摩擦，已知绳与竖直杆间的夹角为θ，则物体A.B.的质量之比m
A.
：m
B.
等于（ ）
A. cosθ：1B. 1：cosθ
tanθ：1
1：sinθ
如图所示用恒力F.通过光滑的定滑轮将静止于水平面上的物体从位置A.拉到位置B.物体可视为质点定滑轮距
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BythetimeRobertPorterAllenwasbornin1905thewhoopingcrane鸣鹤wasalreadyintrouble.ThebeautifulbirdwasoncecommonlyfoundacrossNorthAmerica.By1941thewhoopingcranepopulationhaddwindledtothedoubledigits.ThetallestspeciesinNorthAmericawerecriticallyendangered. Inthe1940stheremainingcranesmigrate以迁徒everyyearfromtheGulfCoastofTexastosomewhereinthenorthofCanadatobreed繁殖.Theconservationcommunitydidn'tknowwherethebirdswent.Thewetlandswheretheyusedtospendwintersweregrowingrarerandrarerastheytinynon﹣migratinggroupofwhoopingcraneswasaliveinLouisianain1941butthegrouphaddisappearedbythetimeAllenstartedhisresearch. In1942AllenundertookthewhoopingcraneprojectOverthenextthreeyearshedidalmostconstantfieldworkthattookhimfromTexasupthecranes'migrationroutetoNebraskaandonintoSaskatchewaninsearchofthenestinggroundofthebirds. Studyingthebirdinitsbreedinghabitatandseeinghowmanybirdswerebornwouldallowconservationiststounderstandhowtohelpthebirdsontheirjourney.Butfindingthewhoopingcrane'snestingsitemeantdifficultandfruitlessairsearchesovernorthernCanada. In1952Allenwroteareportonthewhoopingcrane.Thereportwasawarningcalltotheconservationcommunityonly33migratorywhoopersremainedandtheirnestingsitestillhadn'tbeenfound.TwoyearslaterthewhoopingcranesbreedinggroundsinCanada'sWoodBuffaloNationalParkwerefinallyfoundandAllenheadednorthtostudythemfirsthandanincrediblydifficultjourneyinSprunt'swordsAllensworklaidthegroundworkforconservationistslosavethebirdsTheireffortspaidoffasthenumbersreached57by1970and214by2005.Todaythewhoopingcraneisstilllistedasendangeredbutthereareroughly600birdsalive. 1Whatisthepassagemainlyabout? A.ItisastoryaboutAllen'ssearchingforalostbird. B.ItisastoryaboutthecranesLongmigrationflight C.Itisastoryaboutthecranesurvivingthewinters. D.Itisastoryaboutconservingthewhoopingcrane 2Whatdoestheunderlinedworddwindledmeaninthefirstparagraph? A.Increased B.Reduced C.Stayed D.Limited 3AceilingtothePassagewhichofthefollowingismainlyresponsibleforwhathappenedtotheremainingwhoopingcranes? A.Habitatloss B.Illegalhunting. C.Naturaldisaster. D.Deadlydiseases. 4Whichofthefollowingeventstookplacein1954? A.Thenon﹣migratinggroupofwhoopingcranesdisappeared B.RobertPotterAllenundertookthewhoopingcraneproject. C.Thewhoopingcranesbreedinggroundswerediscovered D.RobertPorterAllenwroteareportonthewhoopingcrane.
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如图如图1中两个被固定的点电荷Q1Q2连线的延长线上有ab两点．Q1带正电检验电荷+q仅受电场力作用t＝0时恰经过b点然后沿ba向右运动其v﹣t图象如图2．则Q2带电从b到a的过程中q的电势能变化情况是．
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如图a所示宽L不计电阻的光滑长轨道固定在水平面内一端装有阻值R的定值电阻．轨道平面内存在竖直方向的匀强磁场磁感应强度B．质量m不计电阻的金属杆放在轨道平面上与轨道垂直．初始时刻金属杆有向右的初速度v0同时受到向左的水平拉力． 1初始时刻流过电阻R上的电流大小 2若流过电阻R上的电流随时间均匀减小试判断金属杆做什么运动 3若在水平变力作用下金属杆匀减速运动到速度为零．要使此过程水平变力始终向左则加速度满足什么条件 4若水平向左的拉力保持功率P不变在图b中定性画出金属杆减速到1m/s的过程中的v﹣t图象本小题可用的数据如下B＝0.5TL＝0.1mR＝0.1ΩP＝0.1Wv0＝3m/s．作图要有必要的理由．．
如图所示闭合金属线框abcd位于水平方向匀强磁场的上方h处由静止开始下落并进入磁场在运动过程中线框平面始终和磁场方向垂直不计空气阻力那么在线框进入磁场过程中线框
布朗运动实验得到某个观察记录如图该图反映了
如图1所示是DIS实验研究动能的大小与物体的质量和运动速度关系实验装置． 1图中的①是传感器可以用来测小车的大小． 2在实验中小车动能EK的大小是用摩擦块滑行的距离s来反映的．这样处理的理论依据是用摩擦块克服摩擦力做功fs的多少来反映小车动能EK的大小由于可看成不变因此EK与距离s成比． 3对多组记录数据先后用s～v图2上s～v2图2下等进行拟合研究均得到类似如图所示图象从中得出该实验合理的结论是．
有四个电源电动势均为6V内阻分别为0.5Ω1Ω2Ω3Ω．选择其中一个电源对阻值为2Ω的电阻R供电为使R上获得的功率最大选择的电源其内阻为
如图所示水平面上放置两根平行的光滑金属导轨其上搁置两根金属棒ab和cd金属棒能在导轨上自由滑动整个装置放在竖直向下的匀强磁场中当ab向右滑动时棒cd
6分SUPPORTWORKER Doyouhavetheabilitytocareforothers?Canyouunderstandhowolderpeoplefeel?Areyouagoodcommunicator?Doyouhavegoodlisteningskills?Canyouworkweekends? IfyouhaveansweredYEStotheabovewewouldliketohearfromyou ☆Startingrateof￡8.56perhour ☆Freeuniform ☆Excellenttraining careers@golden﹣care.com WOWEEMAGAZINE WritersWanted WoweeMagazineislookingforwritersforitswebsite.Payisbasedonthenumberofpeoplewhoreadyourarticles.Youmayalsoreceivefreeticketstoeventsandfreeproductstotest.Thisisagreatopportunitytogetvaluableworkexperience. Wewantpeoplewhoarechattyinterestingpassionateskilled Contactusatinfo@wowee.com. CALLINGALLMODELS Thinkyoucouldbeamodel?Ifsowe'dliketomeetyou! Workingasasuccessfulfashionmodelisn'teasybutitisveryexcitingandcouldbeagreatopportunity. Girlsshouldbeover16withaminimumheightof172cmandboysshouldhaveaminimumheightof182cm.Ifyouareunder16anddonotyethavetherequiredheightwewouldstillbeinterestedinmeetingyoubutyoumustbringaparent. info@top﹣model﹣agency.uk WORKFORCOFFEEBEANS JoinBritain'snumberonecafeatCoffeeBeanswhereeverycafehasthesameaimstocreatefamily﹣liketeamsandtogiveexcellentcustomerservice. ManydifferentkindsofpeoplecomeandworkwithussostartyourcareeratCoffeeBeanstoday ☆Choosethehoursyouwork ☆Getmanagementexperience ☆Shareyourloveofcoffee JoinusasaTeamMemberAssistantManagerofCafeManagerdependingonyourskillsandexperience. Emailusatjobs@coffeebeans.co.uk. 1Whichaddressshouldyouemailatifyouwanttobeasupportworker? A.info@wowee.com B.jobs@coffeebeans.co.uk C.careers@golden﹣care.com D.info@top﹣model﹣agency.uk 2AwriterworkingforWoweeMagazinecan. A.getafreeuniform B.receivefreeticketstoevents C.bringaparent D.chooseworkinghours 3Whatcanwelearnaboutthejobsfromthejobpostings? A.Themodelopportunityisonlymeantforadults. B.Thereisnoneedtobetrainedasasupportworker. C.EmployeesatCoffeeBeanshavefewmanagementopportunities. D.ApplicantstoWoweeMagazineareexpectedtobesociableandenthusiastic.
实验小组在做“验证机械能守恒定律”实验时提出了两种方案甲方案为让小车沿倾斜的木板下滑然后测量相关物理量乙方案为将小球用细长绳悬挂固定后使小球摆动然后测量相关物理量 1你建议选择的方案是填“甲”或“乙”理由是． 2若实验小组选用了乙方案实验装置如图所示．实验中用于测量小球速度的传感器可选用传感器． 3实验前已测得DCBA各点高度分别为0m0.050m0.100m0.150m．某同学获得的实验数据如下表分析表中数据发现从B到C到D机械能逐渐减小其原因是． 次数 D C B A 高度h/m 0 0.060 0.100 0.150 速度v/m/s 1.878 1.616 1.299 0 势能Ep/J 0 0.0039 0.0078 0.0118 动能Ek/J 0.0141 0.0104 0.0067 0 机械能E/J 0.0141 0.0144 0.0146 0.0118 4表中A点的机械能数据明显偏小其原因可能是摆锤的释放点A点选填“高于”“低于”
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.错误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. DearSir/Madam I'mwritinginresponsetoyouradvertisementintheBingleyTimesinMarch2nd.I'mveryinterestinginjoiningyourDanceclassesandwouldbegratefulunlessyoucouldanswerafewquestionsIhave. Youradvertisementstatesthatanumberintheclasseswaskepttoaminimum.Howmuchpeoplearethereineachclass?AsIworkeverydayuntil5o'clockIwouldalsoliketoknowthetimesoftheclasses.InadditionI'dliketoknowifIneedanyspecialshoesfortheclassesandI'dgreatlyappreciateifyoucouldtellmewheretobuyanynecessaryequipments.Finallyasit'smyintentiontoattendtotheseclassesregularlycouldyoualsosendmedetailsofpricesormembershipfees? Thankyouforyourkindattention.Pleasereplyatyourearliestconvenience. Yoursfaithfully ElaineRichards
物体从高处自由下落落地时间为t．若选地面为参考平面当下落时间为时物体所具有的动能和重力势能之比为
如图“离心转盘游戏”中设游客与转盘间的滑动摩擦系数均相同最大静摩擦力等于滑动摩擦力．当转盘旋转的时候更容易发生侧滑向外偏离圆周轨道的是
卢瑟福进行的α粒子散射实验现象表明
如图倾斜固定放置的“Π”形光滑金属导轨位于与水平面成θ角的平面内导轨宽为L电阻不计．宽度均为d的矩形有界匀强磁场ⅠⅡ方向垂直导轨平面向下磁感应强度大小均为B两磁场间的距离也为d．质量为m电阻为R的金属杆ab平行于导轨顶部从距离磁场Ⅰ上边缘h处由静止释放．已知金属杆进入磁场Ⅰ和Ⅱ时的速度相等且始终与导轨接触良好重力加速度为g． 1求金属杆刚进入磁场Ⅰ时的速度v大小 2定性分析金属杆穿过两磁场的过程中能量是如何变化的 3分析并说明金属杆释放处与磁场Ⅰ上边缘的距离h需满足的条件 4作出金属杆从进入磁场Ⅰ到离开磁场Ⅱ这一过程中的v﹣t图象．
8分Asdataandidentitytheftbecomesmoreandmorecommonthemarketisgrowingforbiometric生物测量technologies﹣likefingerprintscans﹣tokeepothersoutofprivatee﹣spaces.Atpresentthesetechnologiesarestillexpensivethough. ResearchersfromGeorgiaTechsaythattheyhavecomeupwithalow﹣costdevice装置thatgetsaroundthisproblemasmartkeyboard.Thissmartkeyboardpreciselymeasuresthecadence节奏withwhichonetypesandthepressurefingersapplytoeachkey.Thekeyboardcouldofferastronglayerofsecuritybyanalyzingthingsliketheforceofauser'stypingandthetimebetweenkeypresses.Thesepatternsareuniquetoeachperson.Thusthekeyboardcandeterminepeople'sidentitiesandbyextensionwhethertheyshouldbegivenaccesstothecomputerit'sconnectedto﹣regardlessofwhethersomeonegetsthepasswordright. Italsodoesn'trequireanewtypeoftechnologythatpeoplearen'talreadyfamiliarwith.Everybodyusesakeyboardandeverybodytypesdifferently. Inastudydescribingthetechnologytheresearchershad100volunteerstypethewordtouchfourtimesusingthesmartkeyboard.Datacollectedfromthedevicecouldbeusedtorecognizedifferentparticipantsbasedonhowtheytypedwithverylowerrorrates.Theresearcherssaythatthekeyboardshouldbeprettystraightforwardtocommercializeandismostlymadeofinexpensiveplastic﹣likeparts.Theteamhopestomakeittomarketinthenearfuture. 1Whydotheresearchersdevelopthesmartkeyboard? A.Toreducepressureonkeys. B.Toimproveaccuracyintyping. C.Toreplacethepasswordsystem. D.Tocutthecostofe﹣spaceprotection. 2Whatmakestheinventionofthesmartkeyboardpossible? A.Computersaremucheasiertooperate. B.Fingerprintscanningtechniquesdevelopfast. C.Typingpatternsvaryfrompersontoperson. D.Datasecuritymeasuresareguaranteed. 3Whatdotheresearchersexpectofthesmartkeyboard? A.It'llbeenvironment﹣friendly. B.It'llreachconsumerssoon. C.It'llbemadeofplastics. D.It'llhelpspeeduptyping. 4Whereisthistextmostlikelyfrom? A.Adiary. B.Aguidebook. C.Anovel. D.Amagazine.
闭合电路中电源的电动势为12V外电压为10V当有2C电量通过电路时该电路中的能量转化情况是非静电力把J的其他形式能量转化为电能静电力把J的电能转化为其他形式能量电源消耗了J的电能．
汽车在平直公路上直线行驶发动机功率保持恒定行驶时所受的阻力恒定其加速度a和速度的倒数图象如图．若已知汽车的质量根据图象信息不能求出
做竖直上抛运动的物体在任意相等时间内速度的变化量
一人站在体重计上．当他静止时台秤指针指在45kg刻度处．则在他快速蹲下的整个过程中台秤指针
Anewstudyhasshownhowcomputersandrobotspoweredbyartificialintelligencecanreadhumaneyemovementstoreadhumanpersonalities. Theeyestheysayarethewindowstothesoul.Andifthatistruecomputersandrobotspoweredbysophisticatedartificialintelligencealgorithms算法maysoonhavetheabilitytopeerintoyoursoul.ThatistheresultofanewstudyontheconnectionbetweeneyemovementsandpersonalityconductedbyneuroscienceresearchersbasedattheUniversityofSouthAustraliaandPublishedinthescientificJournalFrontiersinNeuroscience. EyemovementsduringaneverydaytaskpredictaspectsofourpersonalitywrotetheresearchersledbyUniversityofSouthAustralianeuroscientistTobiasLoetscherwhoseteamfollows42studysubjectsaroundtheuniversitycampusrecordingtheireyemovementsthendeterminestheirpersonalitytraits特点withwell﹣establishedquestionnairesfordeterminingpersonalitytypeaccordingtoasummaryofthestudypublishedbythesiteScienceDaily. TheresearchersfedthedataintotheirAlalgorithmsandfoundthatcomputersrunningthealgorithmswereabletorecordhumaneyemovementsandimmediatelydetermineaperson'smajorpersonalitytraitssuchasneuroticismextraversion外向agreeablenessconscientiousnessaswellasperceptualcuriositythescientistswrote. Thenewfindingscouldimprovethewayhumanbeingsinteractwiththeircomputersandotherhigh﹣techdevicesevenrobotsallowingformorenaturalandrealisticsocialinteractionswithmachinesLoetschersaid. Peoplearealwayslookingforimprovedpersonalizedservices.Today'srobotsandcomputersarenotsociallyawaresotheycannotadapttonon﹣verbalinformationLoetschersaidinastatementquotedbyIndianExpress.Thisresearchprovidesopportunitiestodeveloprobotsandcomputerssothattheycanbecomemorenaturalandbetteratinterpretinghumansocialsignals. ThestudyrevealedpreviouslyundiscoveredrelationsbetweenspecificpersonalitycharacteristicsandspecificeyemovementtendenciesaccordingtoasummaryinBritain'sDailyMailnewspaper. 1WhatdotheunderlinedwordspeerintoinParagraph2probablymean? A.understand B.stareat C.searchfor D.concernabout 2Howdidtheresearchersconducttheresearch? A.Itwascarriedoutinalab. B.42subjects'eyemovementswererecorded. C.Thestudents'dailymovementsweretracked. D.Itssubjects'personalitiesweredeterminedbycomputer. 3AccordingtoTobiasLoetscherwhatcanweknow? A.Robotsandcomputersaresociallyconscious. B.Peoplecarelessaboutimprovedpersonalizedservices. C.Today'srobotsandcomputerscanaccustomtonon﹣verbalinformation. D.Thediscoverywillimprovetheinteractionbetweenhumanbeingsandmachines. 4Whatcanbeasuitabletitleforthetext? A.HumanPersonalityTraits B.WhatHumanEyeMovementsAre C.TellPersonalitiesbyEyeMovements. D.HowHumansandMachinesInteract
如图所示中的两幅图是研究光的波动性时拍摄到的．这属于光的现象如果图中AB分别是用红光和紫光在相同条件下得到的则是用红光得到的．
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A. cosθ：1B. 1：cosθ tanθ：1 1：sinθ
A. cosθ：1B. 1：cosθ tanθ：1 1：sinθ
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