...1.2匀变速直线运动的规律及特例课后巩固训练(含解析...

第课时匀变速直线运动的规律及特例 【测控导航】知识点题号1.匀变速直线运动基本公式的应用5、6、7、10、122.匀变速直线运动推论的应用2、3、83.自由落体运动1、4、94.竖直上抛运动1115题为单选题;69题为多选题1.(2011年重庆卷)某人估测一竖直枯井深度,从井口静止释放一石头并开始计时,经2 s听到石头落底声,由此可知井深约为(不计声音传播时间,重力加速度g取10 m/s2)(b)a.10 mb.20 mc.30 md.40 m解析:石头下落看做自由落体,则h=12gt2=20 m.2.(2011年安徽卷)一物体做匀加速直线运动,通过一段位移x所用的时间为t1,紧接着通过下一段位移x所用的时间为t2,则物体运动的加速度为(a)a.2x(t1-t2)t1t2(t1+t2)b.x(t1-t2)t1t2(t1+t2)c.2x(t1+t2)t1t2(t1-t2)d.x(t1+t2)t1t2(t1-t2)解析:物体做匀加速直线运动,故某段时间内的平均速度等于中间时刻的瞬时速度.设v1=xt1,v2=xt2,由加速度定义式a=vt得a=v2-v1t12+t22=2x(t1-t2)(t1+t2)t1t2,故选项a正确,选项b、c、d错误.3.(2013重庆市一中摸底)飞机从停机坪沿直线滑出,在第1秒内、第2秒内、第3秒内的位移分别是2 m、4 m、6 m,那么(d)a.飞机做匀加速运动b.飞机做匀速运动c.3秒内的平均速度是2 m/sd.3秒内的平均速度是4 m/s解析:由题意不能确定飞机是否做匀加速运动,而且飞机不是做匀速运动,选项a、b错误;3秒内的平均速度是v=2+4+63 m/s=4 m/s,选项d正确,c错误.4.(2012北京朝阳区一模)科技馆里有一个展品,该展品放在暗处,顶部有一个不断均匀向下喷射水滴的装置,在频闪光源的照射下,可以看到水滴好像静止在空中固定的位置不动,如图所示.某同学为计算该装置喷射水滴的时间间隔,用最小刻度为毫米的刻度尺测量了空中几滴水间的距离,由此可计算出该装置喷射水滴的时间间隔为(g取10 m/s2)(c)a.0.01 sb.0.02 sc.0.1 sd.0.2 s解析:第1滴水滴与第2滴水滴的间距为h1=10.0 cm-1.0 cm=9.0 cm,第2滴与第3滴的间距为h2=29.0 cm-10.0 cm=19.0 cm,所以相邻水滴间距之差为h=h2-h1=19.0 cm-9.0 cm=10.0 cm=0.1 m,根据公式h=gt2可知,该装置喷射水滴的时间间隔为t=hg=0.110 s=0.1 s.答案为c.5.(2012云南联考)汽车以24 m/s的速度在平直公路上行驶,急刹车时的加速度大小为4 m/s2,则自驾驶员急踩刹车开始,2 s末与5 s末时汽车的位移之比为(b)a.54b.47c.34d.43解析:自驾驶员急踩刹车开始,经过t0=v0/a=6 s汽车停止运动,所以2 s末汽车的位移为x1=v0t1-12at12=40 m,5 s末汽车的位移为x2=v0t2-12at22=245 m-12452 m=70 m,所以x1x2=47.6.(2013济南外国语学校期中)给滑块一初速度v0,使它沿光滑斜面向上做匀减速运动,加速度大小为g2,当滑块速度大小变为v02时,所用时间可能是(bc)a.v02gb.v0gc.3v0gd.3v02g解析:滑块末速度方向可能沿斜面向上,也可能沿斜面向下,即vt=v02或vt=-v02,所以运动时间可能是t=vt-v0-a=v0g或t=vt-v0-a=3v0g,故选项b、c正确.7.(2012西安质检)一辆汽车拟从甲地开往乙地,先由静止启动做匀加速直线运动,然后保持匀速直线运动,最后做匀减速直线运动,当速度减为0时刚好到达乙地.从汽车启动开始计时,如表给出了某些时刻汽车的瞬时速度,据表中的数据通过分析、计算可以得出汽车(ac)时刻/s1.02.03.05.07.09.510.5速度/(ms-1)3.06.09.012129.03.0a.匀加速直线运动经历的时间为4.0 sb.匀加速直线运动经历的时间为5.0 sc.匀减速直线运动经历的时间为2.0 sd.匀减速直线运动经历的时间为4.0 s解析:汽车做匀加速直线运动的加速度为a1=v2-v1t2-t1=6.0-3.02.0-1.0 m/s2=3.0 m/s2,匀加速直线运动经历的时间t1=va1=123.0 s=4.0 s,选项a正确,选项b错误;汽车做匀减速直线运动的加速度大小为a2=v3-v4t4-t3=9.0-3.010.5-9.5 m/s2=6.0 m/s2,匀减速直线运动经历的时间t2=va2=126.0 s=2.0 s,选项c正确,选项d错误.8.(2013宜宾二中高三上学期期中)完全相同的三个木块并排地固定在水平面上,一颗子弹以速度v水平射入,若子弹在木块中做匀减速直线运动,且穿过第三块木块后速度为零,则子弹依次射入每一木块时的速度比和穿过每一木块所用时间比分别是(bd)a.v1v2v3=321b.v1v2v3=321c.t1t2t3=123d.t1t2t3=(3-2)(2-1)1解析:子弹受到的摩擦力f一定,故加速度也一定,由x=12at2和x1=x2=x3得,t1t2t3=(3-2)(2-1)1由v=at得,v1v2v3=(t1+t2+t3)(t2+t3)t3=321,故选项b、d正确.9.如图所示,小球从竖直砖墙某位置静止释放,用频闪照相机在同一底片上多次曝光,得到了图中1、2、3、4、5所示小球运动过程中每次曝光的位置.连续两次曝光的时间间隔均为t,每块砖的厚度为d.根据图中的信息,下列判断正确的是(bcd)a.位置“1”是小球释放的初始位置b.小球做匀加速直线运动c.小球下落的加速度为dt2d.小球在位置“3”的速度为7d2t解析:由题图可知相邻相等时间间隔的位移差都为d,选项b对;由x=at2=d可知选项c对;位置“3”是小球从位置“2”到位置“4”的中间时刻,据推论有v3=3d+4d2t=7d2t,选项d对;位置“1”到位置“2”的距离与位置“2”到位置“3”的距离之比为23,位置“1”不是小球释放的初始位置,选项a错.10.(2013重庆市一中摸底)以72 km/h的速度行驶的列车,临时需要在某中途车站停车,因此以大小为0.4 m/s2的加速度减速进站,停车2 min,然后以0.5 m/s2的加速度匀加速出站,最后恢复原运行速度.试计算该列车此次因临时停车共耽误多长时间.解析:根据题意,列车匀减速运动阶段,v0=72 km/h=20 m/s,a1=-0.4 m/s2,vt=0,由vt=v0+a1t1解得列车匀减速运动时间t1=50 s.匀减速运动位移x1=v0t1+12a1t12=500 m.停车时间t2=2 min=120 s.匀加速运动阶段,v0=0,a2=0.5 m/s2,vt=20 m/s.由vt=v0+a2t3解得列车匀加速运动时间t3=40 s.匀加速运动位移x2=12a2t32=400 m.因临时停车行驶总位移x=x1+x2=900 m,时间t=t1+t2+t3=210 s,若不停车,列车匀速运动需要时间t=x/v0=45 s.此次因临时停车共耽误时间t=t-t=210 s-45 s=165 s.答案:165 s11.(2012德州模拟)在竖直的井底,将一物块以11 m/s的速度竖直地向上抛出,物块冲过井口时被人接住,在被人接住前1 s内物块的位移是4 m,位移方向向上,不计空气阻力,g取10 m/s2,求:(1)物块从抛出到被人接住所经历的时间;(2)此竖直井的深度. 解析:(1)设被人接住前1 s时刻物块的速度为v,则h=vt-12gt2故v=h+12gt2t=4+1210121 m/s=9 m/s则物块从抛出到被人接住所用总时间为t=v-v0-g+t=9-11-10 s+1 s=1.2 s.(2)竖直井的深度为h=v0t-12gt2=111.2 m-12101.22 m=6 m.答案:(1)1.2 s(2)6 m12.(2013成都六校联考)卡车原来以10 m/s的速度在平直公路上匀速行驶,因为路口出现红灯,司机从较远的地方开始刹车,使卡车匀减速前进,当车减速到2 m/s时,交通灯转为绿灯,司机当即停止刹车开始加速,并且只用了减速过程的一半时间就加速到原来的速度,从刹车开始到恢复原速共用了12 s.求:(1)减速与加速过程中的加速度大小;(2)开始刹车后2 s末及10 s末的瞬时速度大小.解析:(1)卡车先做匀减速运动,再做匀加速运动,其运动简图如图所示,设卡车从a点开始减速,则va=10 m/s,用了t1时间到达b点,从b点又开始加速,用时t2到达c点,则vb=2 m/s,vc=10 m/s,且t2=12t1,t1+t2=12 s,可得t1=8 s,t2=4 s.由v=v0+at得,在ab段,vb=va+a1t1在bc段,vc=vb+a2t2联立两式,并代入数据解得:a1=-1 m/s2,a2=2 m/s2.(2)2 s末的速度为v1=va+a1t=10 m/s-12 m/s=8 m/s,10 s末的速度为v2=vb+a2t=2 m/s+2(10-8)m/s=6 m/s.答案:(1)1 m/s22 m/s2(2)8 m/s6 m/s以下是大学体验英语综合教程2(第三版)课后翻译答案unit11. 任何年满18岁的人都有资格投票。(be eligible to, vote)answer:anyone over the age of 18 is eligible to vote.2. 每学期开学前，这些奖学金的申请表格就会由学校发给每一个学生。(apply for, scholarship)answer:a form to apply for these scholarships is sent by the university to every student before the start of every semester.3. 遵照医生的建议，我决定戒烟。(on the advice of)answer:on the advice of my doctor, i decided to give up smoking.4. 公园位于县城的正中央。(be located in)answer:the park is located right in the center of town.5. 这所大学提供了我们所需的所有材料和设备。(facilities)answer:the university provides all the materials and facilities we desire.1. 他们花了多年的时间寻找内心的平静，但是收效甚微。(search for)answer:they spent many years searching for peace of mind, but with little success.2. 这种新药的成功研制已经使许多疾病的治疗发生了根本性的变革。(revolutionize)answer:the successful development of the new drug has revolutionized the treatment of many diseases.3. 由于这个国家的经济不景气，这家公司濒于破产。(on the edge of)answer:the company is on the edge of bankruptcy due to the economic depression in the country.4. 大学毕业后他成为了一名护士。他认为护士这一职业可能很有发展前途。(rewarding)answer:he became a nurse after college. he thought nursing could be a very rewarding career.5. 他像往常一样在文件上签了名。(just as)answer:he signed his name on the paper just as he has always done it.unit21. 警察们正忙着填写关于这场事故的各种表格。(fill out)answer:the policemen are busy fi lling out forms about the accident.2. 我想在还车之前把油箱加满。(fill up, fuel tank)answer:i want to fi ll up the fuel tank before returning the car.3. 如果你要投诉，最好遵循正确的程序。(follow the procedure)answer:if you want to make a complaint, youd better follow the correct procedure.4. 要不是约翰帮忙，我们绝不会这么快就完成实验。(without)answer:we couldnt have fi nished the experiment so soon without johns help.5. 暴风雨之后，岸边的人们焦急地搜索湖面以期发现小船的踪迹。(scan for)answer:after the storm, the people on the shore anxiously scanned the lake for any sign of the boat.1. 这个国家不大，但是在国际事务中它却发挥着重要作用。(play a role)answer:this country is not big, but it plays an important role in international affairs.2. 正是在我叔叔的帮助下，我得以克服困难，按时完成了任务。(it is . that)answer:it was with the help of my uncle that i overcame the difficulty and completed the assignment in time.3. 毕业时他决定留在北京，而他最好的朋友却选择了去西藏。(while)answer:while he decided to stay in beijing upon graduation, his best friend chose to go to tibet.4. 在这次校园英语演讲比赛中，我们班的玛丽获得了第三名。(come in)answer:in this campus english speaking contest, mary from our class came in third.5. 你应该知道学习弹钢琴需要有时间，有金钱，还要有毅力。(as well as)answer:you should know that it takes time, money as well as perseverance to learn to play the piano.unit31. 我发现量入为出地过日子越来越难了。(increasingly)answer:i find it increasingly difficult to live within my income.2. 现代政治家们都试图以电视讲话来影响普通百姓。(reach out)answer:modern politicians try to reach out to ordinary people in their tv speeches.3. 应该帮助学生对人生采取积极的态度。(adopt)answer:pupils should be helped to adopt a positive attitude to life.4. 希望全班同学参加这些讨论。(participate in)answer:everyone in the class is expected to participate in these discussions.5. 如果你犯了罪就必须受到惩罚。(crime)answer:if you commit a crime you must expect to be punished.1.儿子的死让老妇人变得麻木痴呆了。(numb)answer:the old woman was numbed by her sons death.2.身处所有这些烦恼之中，他依然能保持乐观。(in the midst)answer:in the midst of all troubles, he managed to remain cheerful.3. 虽有困难，他们还是设法坚持试验下去。(carry on)answer:they managed to carry on their experiments in spite of the difficulties.4.我们必须淘汰不合格的申请人。(weed out)answer:we have to weed out unqualified applicants.5. 医生要他减少抽烟。(cut down on)answer:the doctor told him to cut down on smoking.unit41.她在公共汽车站一直等到末班车进站。(come in)answer:she waited at the bus stop until the last bus came in.2.如果我们能帮得上忙，尽管和我们联系。(contact)answer:if there is any way we can be of assistance, please do not hesitate to contact us.3 .他需要多少船务人员才能使他的游艇航行？(crew, yacht)answer:how many crew does he need to sail his yacht?4 .虽然她的新书没有上一本好，但是我还是喜欢它。(not quite as)answer:i enjoyed her new book though its not quite as good as her last one.5 .我从未遇到过如此善良的人。(never before)answer:never before have i met such a kind person.1.公共汽车放慢速度并停下，让那位乘客上车。(slow down)answer:the bus slowed down and stopped to allow the passenger to get on board.2.许多车子都驶过去了，可是没有一辆愿意让我们搭便车。(roll by)answer:many vehicles rolled by, but no one offered us a ride.3 .请勿践踏草地。(get off)answer:please get off the grass.4.他按妻子的吩咐，一下班就去了市场。(make ones way)answer:he made his way to the marketplace right after work, as his wife had asked him to do.5 .值得庆幸的是，史蒂夫 (steve) 从自行车上摔下来时没有摔断骨头。(luckily)answer:luckily, steve didnt break any bones when he fell off his bike.unit51. 我们得把感情放在一边，从专业的角度来对待这件事。(from a professional standpoint)answer:we have to put aside our emotions and take it from a professional standpoint.2. 这部戏非常精彩，我很快就沉浸于激动人心的剧情之中。(lose oneself in)answer:the play was so wonderful that i soon lost myself in the excitement of it.3 .她没有什么爱好除非你把看电视也算是一种爱好。(unless)answer:she hasnt got any hobbies unless you call watching tv a hobby.4. 他说他是直接从市长本人那里得到这个信息的。(first-hand)answer:he said that he had got the information first-hand from the mayor himself.5 .既然你不能回答这个问题，我们最好问问别人。(since)answer:since you cant answer the question, perhaps wed better ask someone else.1. 由于公共汽车司机突然刹车，旅客们都不由自主地向前摔倒。(brake, pitch forward)answer:all the passengers pitched forward because the bus driver braked sharply.2. 这个协议将冲破对自由贸易设置的障碍。(break through, obstacle)answer:this agreement will break through the obstacles to free trade.3 .我刚放下叫出租车的电话，车就来了。(soon after)answer:the taxi arrived soon after i rang for it.4. 在过去，不管我什么时候到家，我父母总会等我。(no matter)answer:my parents always waited up for me no matter what time i got home.5 .由于没有一方愿意让步，两个公司之间的对话完全破裂了。(break down)answer:talks between the two companies completely broke down, because neither of them wanted to give in.unit61. 那件工作很难做，不过我想试试看。(have a shot)answer:its a difficult job, but id like to have a shot.2. 这是一本关于商务实践而非理论的书。(as opposed to)answer:this is a book about business practice as opposed to theory.3. 社会活动从未耽误她的学习。(in the way)answer:social activities never get in the way of her studies.4. 直到1911年人们才发现第一种维生素。(it is not until . that)answer:it was not until 1911 that the first of the vitamins was identified.5. 尽管年事已高，爷爷每天还帮忙做家务。(despite)answer:despite advanced years, grandpa helps do housework every day.1. 我们的婚姻很幸福，但我们也曾经历过许多坎坷。(ups and downs)answer:our marriage is happy but weve had many ups and downs.2. 许多外语教师常常在课堂上自顾自地讲得太多。(be inclined to)answer:many teachers of foreign languages are inclined to talk too much themselves in class.3. 那位著名演员每天早晨锻炼一小时以保持健康。(work out)answer:the famous actor keeps fit by working out for an hour every morning.4. 与他促膝长谈之后，她的怀疑消失了。(melt away)answer:after a long heart-to-heart talk with him, her suspicion melted away.5. 目前我们没有职位空缺，但我们肯定会记住您的申请。(keep in mind)answer:we have no vacancies now, but well certainly keep your application in mind.unit71. 他并不后悔说过的话，只是觉得他完全可以不用这种方式表达。(could have done)answer:he did not regret what he had said but felt that he could have expr