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如图所示，打点计时器固定在轨道上端，纸带穿过打点计时器与小车相连，平衡好摩擦力后接通电源，打点计时器工作，轻推小车使之匀速下滑（车轮不打滑），纸带上留下清晰的点迹． （1）已知交流电源的频率为f，...
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高三下学期物理《》真题及答案
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一电火花打点计时器固定在斜面上某处一小车拖着穿过打点计时器的纸带从斜面上滑下如图2－1－5甲所示.图
使用打点计时器时应注意A.无论使用电磁打点计时器还是电火花计时器都应该把纸带穿过限位孔再把套在轴上的
一个有一定厚度的圆盘可以绕通过中心垂直于盘面的水平轴转动用下面的方法测量它匀速转动时的角速度实验器材
在验证机械能守恒定律的实验中1下列实验操作顺序正确合理的一项是________填序号A.先将固定在重
一电磁打点计时器固定在斜面上某处一滑块拖着穿过打点计时器的纸带从斜面上滑下如图甲所示.1电磁打点计时
在用打点计时器测速度的实验中用打点计时器在纸带上打点以记录小车的运动情况在这一实验中操作实验步骤如下
一电火花打点计时器固定在斜面上某处一小车拖着穿过打点计时器的纸带从斜面上滑下如下图甲所示.1电火花打
在验证机械能守恒定律的实验中1下列实验操作顺序正确合理的一项是填序号A.先将固定在重物上的纸带穿过打
在验证机械能守恒定律的实验中1下列实验操作顺序正确合理的一项是________填序号A.先将固定在重
如图所示的四条纸带是某同学练习使用打点计时器得到的纸带纸带的右端后通过打点计时器.从点痕的分布情况可
测定匀变速直线运动的加速度实验中主要步骤有A.换上纸带重复做三次选择一条较为理想的纸带B.将打点计时
一打点计时器同定在斜面上某处一小车拖着穿过打点计时器的纸带从斜面上滑下如图所示.下图是打出的纸带的一
某同学利用如图所示的装置研究匀变速直线运动时记录了下列实验步骤合理的操作顺序是___________
把一条细绳拴在小车上，使细绳绕过滑轮，下边挂上合适的钩码。把纸带穿过打点计时器，并把纸带的一端固定在小车的后面。
把附有滑轮的长木板平放在实验桌上，并使滑轮伸出桌面。把打点计时器固定在长木板上没有滑轮的一端，连接好电路。
把小车停在靠近打点计时器处，接通电源后，放开小车，让小车拖着纸带运动，打点计时器就在纸带上打下一行小点，随后立即关闭电源。
换上新纸带，重复操作三次。
用打点计时器时应注意
无论使用电磁打点计时器还是电火花打点计时器，都应该把纸带穿过限位孔，再把套在轴上的复写纸片压在纸带的上面
使用打点计时器时应先接电源，再拉动纸带
使用打点计时器在拉动纸带时，拉动的方向应与限位孔平行
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用打点计时器时应注意
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使用打点计时器时应先拉动纸带，再接通电源
使用打点计时器在拉动纸带时，拉动的方向应与两个限位孔连线平行
使用打点计时器应将计时器先固定在桌子上
一打点计时器固定在斜面上某处一小车拖着穿过打点计时器的纸带从斜面上滑下如图甲所示图乙所示是打出的一段
某同学利用如图所示的装置研究匀变速直线运动时记录了下列实验步骤合理的操作顺序是___________
把一条细绳拴在小车上，使细绳绕过滑轮，下边挂上合适的钩码。把纸带穿过打点计时器，并把纸带的一端固定在小车的后面。
把附有滑轮的长木板平放在实验桌上，并使滑轮伸出桌面。把打点计时器固定在长木板上没有滑轮的一端，连接好电路。
把小车停在靠近打点计时器处，接通电源后，放开小车，让小车拖着纸带运动，打点计时器就在纸带上打下一行小点，随后立即关闭电源。
换上新纸带，重复操作三次。
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Theartofpaper﹣cuttinginChinamaydatebacktothesecondcenturysincepaper61inventbyCaiLunintheEasternHanDynastyinChina.Aspaperbecamemoreaffordablepaper﹣cuttingbecameoneofthemostimportant62typeofChinesefolkart.Later63differentregionsadoptingtheirownculturalstylesthisartformspreadtootherpartsoftheworld64usualtheartworksaremadeofredpaperasredisassociatedwith65happyinChineseculturebutothercolorsarealsoused. With66itlonghistorypaper﹣cutting67originatedinChinahasbeenverypopularamongtheordinaryChinesepeople.Peopleputuppapercutsonwallswindowsanddoorsatweddingceremoniesorfestivals68strengthenthecheerfulatmosphere. Chinesepapercutsarerichincontent.Theauspicious吉祥的designssymbolizegoodluckandtheavoidanceofevil.Thechildlotusandbatdesignssuggestafamilywith69largenumberofchildrenandgrandchildren.Birdslivestockfruitfishandwormsarealsofamiliarobjects70acceptbyChinesefarmers.Inawordpapercutsusedindifferentoccasionshavedifferentmeanings.
王斌同学在解答问题“同时掷两个骰子计算向上的点数之和是5的概率是多少”时给出了如下答案 记{mn}为投掷两个骰子向上点数分别为mn 则投掷两个骰子的所有可能结果为 {11}{12}{13}{14}{15}{16}{22}{23}{24}{25}{26}{33}{3.4}{35}{36}{44}{45}{46}{55}{56}{66}共计21种． 其中“向上的点数之和是5”的有{14}和{23}共2个． 所以所求概率为． Ⅰ你认为王斌同学的解答正确吗简述理由． Ⅱ如果王斌同学的解法不正确请在下面给出正确的解答．
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已知函数则函数fx的导函数f'x等于
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为检验某卤代烃R﹣X中的X元素下列操作1加热煮沸2加入AgNO3溶液3取少量该卤代烃4加入足量稀硝酸酸化5加入NaOH溶液6冷却．正确的操作顺序是
LookingUp IcanstillrememberthewaymytennisshoeslookedasIstareddownatthemfeelinganxiousaboutwhatwasabouttotakeplace.Itwastimefortheweeklyeleventh﹣gradevolleyballgame.IknewIwouldneverbethebest36onanyteam.ButeveryweekIstaredatmyshoesandsimplywishedIwouldn'tbepicked37.AndyetIwaslastalmosteverytime.Noteamwantedthegirlwhoalways38theballandmissedtheeasyserves. YearslaterIrealizedhowmuchthosemomentsof39hadaffectedme.Ibegantoexpectthe40ineverysituationrepeatedlytellingmyselfthatIjustwasn'tgoodenough.Igrewupstaringatmy41. Allthatbeganto42duringthesummervacationinhighschool.Mymom'ssisterAuntKarenofferedmeapart﹣timejob.IhadalwaysadmiredAuntKaren43shewassuccessfulandledsuchanexcitinglife.Hergoodmannerandwarmsmileweretotallydifferentfromthe44wayIapproachedtheworld.Butthatsummershetaughtmetolookatthings45. AuntKarensaidthatthesecret46successcomesfromtheinsidenottheoutside.Iwasshockedtolearnherexperiencehadbeensimilartomine.Shehadn'tbeengoodat47either!AuntKarensaidshefinallyrealizedwhatotherpeoplethoughtofherdidn't48asmuchaswhatshethoughtofherself.Shetoldmewhenshestartednoticingherowngoodqualitiesshe49beingsoself﹣critical. SothatsummerItookher50toheart.IlistenedtowhatIwassayingtomyselfanddecidedtofocusmoreonthegood.ForexamplewhenImisfiledanimportantpaperI51myselfofalltheotheronesIhadfiledcorrectly.AndwhenIwasshownthedirtyclosetIsaidtomyselfthatIwouldbegreatat52it.BeforelongIhadlearnedavaluablelesson.53thinkingactuallyworks! BythetimeschoolstartedthatfallIwasmuchmore54.Iwentalongwithpeoplearoundmewithatotallydifferentattitude.Whenmychemistryteacherannouncedthatweshouldeachfindalabpartner55lookingdownatmyshoesIlookedupandsmiled.Anddoyouknowwhathappened?Averynicegirlimmediatelyaskedmetobeinonegroup! 36. A.player B.teacher C.worker D.manager 37. A.fast B.soon C.only D.last 38. A.liked B.dropped C.sold D.studied 39. A.relaxation B.celebration C.rejection D.discussion 40. A.worst B.best C.latest D.least 41. A.hands B.shoes C.shorts D.legs 42. A.change B.continue C.settle D.grow 43. A.if B.unless C.until D.because 44. A.proper B.nervous C.careless D.comfortable 45. A.kindly B.seriously C.carefully D.differently 46. A.to B.with C.from D.at 47. A.chemistry B.language C.sports D.computer 48. A.stand B.matter C.cost D.expect 49. A.minded B.practiced C.stopped D.suffered 50. A.steps B.plans C.time D.advice 51. A.reminded B.rid C.warned D.accused 52. A.repairing B.cleaning C.designing D.decorating 53. A.Critical B.Deep C.Positive D.Creative 54. A.confused B.careful C.cautious D.confident 55. A.inchargeof B.inspiteof C.insteadof D.incaseof
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∧并在此符号下面写出该加的词. 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. ThemostimportantfestivalinTibetistheTibetanNewYearinJanuary1stoftheTibetancalendar.ItisforsaygoodbyetothepastyearanwelcomingtheNewYear.Frommid﹣Decemberpeoplestarttoprepareordofestivalshopping.AlotofactivityareheldinthestreetsoftheLhasaduringtheNewYearFestival.Thereisaninterestedcompetitiononthisday.Ayoungmanfromeachfamilytriedtogetthefirstbucketofwaterfromtheriver.Itisbelievedbegoldwater.AccordingtotheTibetantraditiontheywillbringgoodluckhappinessandwealthtothosewhichgetit.
对于定义在R上的函数fx下列命题 ①若f-2=f2则函数fx一定为偶函数 ②若f-2≠f2则函数fx一定不是偶函数 ③若f-2=f2则函数fx一定不是奇函数． 其中正确的命题的序号是把所有正确命题的序号都填上．
HowtoBecomeaMorningPerson? Herearesomehabitsyoucanfocusonthatcanhelpyoubecomeabettermorningperson 36 Forfiveminuteseachmorningwritethreethingsyouaregratefulfortoday.Practicinggratitudeaboutwhatwehavegoingforuscanrestructureourbraintofocusonpositivethings. Alwayshavebreakfast Ifyou'repressedfortimepicksomething.Abreakfastgivesyouenergyandit'sfuelforyourbrain. Tryreflecting Reflectingearlyinthedayevenfor10minuteshelptocleanyourbrainofanydisorderedthoughts.37.WithanappcalledHeadspaceyoucantryaguided10﹣minutereflection. Getmoving Toreallywakeyourentirebodyuppickanytypeofphysical.38oritcanbesomethingshorterandevensimpleramorningyogaroutine. Light Leaveyourbedroomcurtainsopen.39holdingbackmelatonin褪黑素productionandwakingyouup.Trytoexposeyourselftoasmuchsunlightaspossible. Enoughsleep ThismightseemobviousbutmostAmericansdon'tgetenoughsleepthesedays.Andifyou'reshortonsleepyou'lltendtosleeplate.Withtimethatwillpushyouintoalaterandlatersleepcycle. 40.Somepeopleseemtobemorningpeoplesomenightpeople. A.Developapositiveattitude B.Forceyourselftogetupinthemorning C.Keepagratitudediary D.Itcanbeanexerciseatthegym E.It'snotasdifficultasitsounds F.Thiswillallownaturalsunlighttocomein G.Andfinallyrememberthatpeoplediffer.
Howdoyoupayforthingsinashop?Perhapsyoulikethetouchablereliabilityofhardcash?Maybethefinancialflexibilityofacreditcardsuitsyoubetter?Orperhapsyoupreferthesimpleconvenienceofasmartphone? Whateveryouusetodayexpertsbelieveallthesemethodscouldsoonbecomeoutdated.Insteadwewilluseourbodiesoureyesourfingerprintsevenourmerepresenceinthestore.Infactit'shappeningalready.Amazonaretrialingstoreswhichhavenocheckoutswheretechnologytrackstheitemsyou'vetakenfromtheshelvesanddeducts扣除thetotalfromyouraccountwhenyouleavetheshop. FrenchsupermarketMonoprixtakesadifferentpathyouchooseyourgroceriesandleavethemwithahumancashier.Youthenleavetheshopwhilethecashieraddsupyourbillchargesyouraccountandorganizesdeliverytoyourhome. AmirCEOofBarclaycardpredictsthatsuchnewdevelopmentsmeantheendoftheplasticcreditcard.Insteadwearableitemssuchasringsnecklacesandkeychainswillcarrychips芯片thatallowshopperstoshopgoingbetweenthewebanapporinstore. Andwhilealltheabovepaymentmethodsaresupportedbyaccountsheldintraditionalcurrencieslet'snotforgettheriseofalternativessuchasLitecoin.Virtual虚拟currenciescanriseinvalueveryquickly.OnesuchpossibilityisexploredinthemovieInTime.Itimaginesafuturisticsocietyinwhichthecurrencyistimeitselfwherepeopletradetheamountoftimetheyhavelefttolive. Orperhapswe'ddobettertowindbacktheclocktothesimplerfinancialworldoftheequalexchangeeconomy.Whilethetermrecallsimagesofbagsofgrainandherdsofsheepbeingexchangedinancienttimestherearesignsthataremakingacomebackintoday'sworldofmoderntechnology.Maybetheonlythingweknowforcertainisthatmoneywillkeepupdating. 28.WhichofthefollowingstatementsisTRUE? A.PaymentisdonebythecashiersatAmazon. B.Allthemethodsofpaymenthavebecomeoutdated. C.ShoppingatMonoprixisconvenientforcustomers. D.CustomerscanleavetheircreditcardsatMonoprix. 29.WhatmightreplacethecreditcardsinthefutureaccordingtoAmir? A.Smartphones. B.Wearableitems. C.Virtualcurrencies. D.Fingerprints. 30.WhatisusedasacurrencyinthemovieInTime? A.Litecoin. B.Humanlife. C.Time. D.Bagsofgrain. 31.Whichisthebesttitleforthepassage? A.TheRiseofVirtualCurrencies. B.TheHistoryofMoney. C.TheEndingifCreditCards. D.TheChangingNatureofMoney.
有机物甲的分子式为C3H7Br在适宜的条件下能发生如下转化关系 已知B能发生银镜反应试回答下列问题 1甲的结构简式． 2B与银氨溶液反应的化学方程式． 3甲与NaOH醇溶液共热的化学方程式为． 4A与氧气反应生成B的化学方程式． 5D生成E的化学方程式．
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