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      高一 1 教案(合集五篇)

      時(shí)間:2019-05-13 22:38:50下載本文作者:會(huì)員上傳
      簡(jiǎn)介:寫(xiě)寫(xiě)幫文庫(kù)小編為你整理了多篇相關(guān)的《高一 1 教案》,但愿對(duì)你工作學(xué)習(xí)有幫助,當(dāng)然你在寫(xiě)寫(xiě)幫文庫(kù)還可以找到更多《高一 1 教案》。

      第一篇:高一 1 教案

      高一上冊(cè) unit 1 教案

      資料說(shuō)明:

      一、Goals & Contents 1.Knowledge A.words(basic)

      honest, brave, loyal, wise, handsome, smart, classical, fond of, match, mirror, fry, gun, hammer, saw, rope, movie, cast, deserted, hunt, hunt for, in order to, share, sorrow, care about, feeling, such as, airplane, lie, speech, adventure, notebook, drop a line, error ,survive, be into B.words(optional)solution, compass, , parac 教材年級(jí):人教修訂版-高一 學(xué)期單元:上學(xué)期-01 上 傳 人: li_xukui 審 核 人: webmaster 來(lái)

      源: 整理 瀏覽次數(shù): 1146 上傳時(shí)間: 2006-9-27 11:20:53 >> 下載需要:5 個(gè)英幣

      Unit 1 Good Friends

      By Yin Qingguo

      一、Goals & Contents 1.Knowledge A.words(basic)

      honest, brave, loyal, wise, handsome, smart, classical, fond of, match, mirror, fry, gun, hammer, saw, rope, movie, cast, deserted, hunt, hunt for, in order to, share, sorrow, care about, feeling, such as, airplane, lie, speech, adventure, notebook, drop a line, error ,survive, be into B.words(optional)

      solution, compass, , parachute, scared, formal, hike C.Sentences

      I don’t enjoy singing, nor do I like computers.I hate hiking and I’m not into classical music.Chuck is a businessman who is always so busy that he has little time for his friends.Chuck is on a flight across the Pacific when suddenly his plane crashes.He realizes that he hasn’t been a very good friend because he has always been thinking about himself.He also learns that he should have cared more about his friends.D.Phrases

      have little time, surf the Internet, all the time, on a flight, survive the crash, a deserted island, all alone, collect water, hunt for food, make fire, develop a friendship, share happiness and sorrow, have someone to care about, to give as much as to take E.Grammar

      Direct speech and Indirect speech.2.Ability & Function

      ① Learn how to describe friends.② Learn how to express your likes and dislikes ③ Learn how to make / offer apologies

      ④ Learn how to change the direct speech into indirect speech and vice visa.⑤ Learn how to compose an e-mail.二、Schedule and Procedures 1.Time Allotment

      Period 1---Warming up & Speaking Period 2---Listening & Talking

      Period 3&4---Reading(plus“Pre-”&“Post-”& language study)Period 5&6---Language study& Practicing Period 7&8---Integrating skills &Assessing 2.Procedures

      Period 1

      Warming up & Speaking

      Step One:Warming up

      Teaching aims: how to describe a good friend talking about likes and dislikes 1.Words to be studied

      honest, brave, loyal, wise, handsome, smart, classical, be fond of, be into, classical, hobby 2.Making sentences using the words above, for example, I think a friend should be honest.He or she never tells lies.A good friend is someone who is brave.He or she is not afraid of difficulties.……………… How to carry it out: 1.Greetings to the Ss:

      Good morning, everyone!Stand up!Sit down, please!Class is over!How are you today?

      2.Do you have a good friend?/ what do you think should a good friend be like?/ what qualities should a good friend have? The students are asked to describe one of their good friends.Let them use as many adjective words as possible.At the same time I will write these words on the blackboard.Then I will explain some new adjective words.And ask Ss.to make sentences using them.Step Two: Speaking

      Teaching aims: learn how to express your hobbies: likes and dislikes 1.Words and phrases to be studied

      be into, fond(of), classical, all the time, surf the internet not……nor/neither…… 2.Useful expressions

      love sth./ to do / doing doesn’t/don’t like/ love sth like sth./to do / doing I think that……is terrible or boring.enjoy sth./ doing sth.hate to do/doing sth.be into sth.be not into sth.be fond of sth./ doing sth.I can’t stand……

      be crazy about sth.don’t/doesn’t enjoy sth./doing sth.How to carry it out:

      1.Ask them to make a self-introduction

      Hi, my name is…….I am ……years old.And I like ……, I don’t like……, etc.2.How to introduce their friends

      Hi, everybody.…… is my good friend.He is …….He likes …….He doesn’t like …….We’re friends because we have the same interests.3.First ask the Ss.to read the text themselves.And then fill in the chart on page three.After that I will check the answers together.Then I will divide them into several groups and let them discuss the question who can be good friends.After about 5 minutes, I will ask them to answer it trying to use the useful expressions and tell the reasons.(A group survey)Name Terry Gender Male Age 24

      Quality Optimistic Honest Likes Basketball Traveling Music

      Dislikes Swimming Telling lies

      Period 2

      Listening & Talking

      Step One: Listening

      Teaching aims: how to deal with the problems or misunderstandings happened among good friends.How to carry it out:

      1.Ask the Ss.to listen and find out what they(two friends)are arguing about and give suggestions to them in oral or written form.2.Go on listening on WB on page 85.3.Ask the Ss.if they have some other ways/methods to solve such problems.First divide them into several groups and then give them 5 minutes to discuss it.Let them decide what the most effective way to solve such problems is.Keys to textbook on page 2

      1.Peter is often late for football practice.I think that he should try to be on time in the future.2.Mary usually borrows things without asking and she doesn’t return things on time.She should ask the owner is she wants to borrow something and try to return it on time in the future.3.Adam borrowed John’s CD player yesterday and now it is broken.Adam can ask his uncle to fix it.Keys to workbook on page 85

      1.Solution: Try to understand your friend/Try to talk about the problem in a different way.2.Solution: Start by telling each other that you are sorry and take it from there.A simple apology is often enough.3.Solution: Keep your secrets to yourself.Step two: Talking

      Friends often help each other.But sometimes there are some misunderstandings or unpleasant things occurring among them.To learn the skills or strategies is very important to keep good friendship.Under such circumstances, a simple apology is enough and works well.But how to make apologies?

      Teaching aims: how to make apologies between friends when some unhappy/unpleasant things or misunderstandings occur.Words and useful expressions: work vi.工作,起作用,行得通

      a.She works in a restaurant.b.The machine won’t work.c.Your suggestion works well.why did/didn’t you……?

      You promised to …… I am very sorry…… Please forgive me.I forgot.It won’t happen again.You said that you would…… How to carry it out:

      1.Study the example on page 85.First, hand out cards.Divide the Ss.into several groups, and let them choose their cards and make a short conversation using the expressions on page 86.Then I will check it one by one.2.Finish the exercises 2 on page 86.3.Think of some other situations and let the Ss.discuss and find out the solutions and then act them out.Homework: a.copy some words

      b.make a name card.(full name, age, likes, dislikes……)

      Period 3&4 Reading How to carry it out: Pre-reading:

      1.Ask the Ss.to read the questions of pre-reading.First I will explain some new words.Match: a piece of short wood which can be used to make fire.Some phrases: strike a match;put a match to sth;matchbox(box for holding matches).Mirror: a piece of glass which can be used to reflect images.Some phrases: a driving-mirror;a hand mirror;look at yourself in the mirror.Fry: to cook or be cooked in boiling fat or oil.Gun: a kind of small weapon, which can be used to kill both persons and animals and of course you may use it to protect yourself.Hammer: you may use a hammer to hammer a nail into the wood.Saw: this is a kind of tool that can be used to cut the wood into two or pieces, but it is not a knife.Rope: 繩子

      Compass: the instruments that can be used to distinguish the directions.2.Then let them make up sentences using the new words.3.I have to divide the class into seven groups, in each group there will be eight students.And I will make them discuss the questions and illustrate their reasons.I will make the students elect one captain for each group and report their reasons.The captain of each group can have a same idea or a different one.Then if the other groups don’t agree with the speaking group, they can debate.I think a knife is the most useful, because I could use it to cut things, to fight animals, and to …….Andy thinks that a box of matches is the most useful, because …… Reading the whole text:

      1.Brief introduction to Tom Hanks

      2.Some background knowledge to this famous film Cast Away

      3.List some simple questions on this passage to let the Ss.find the answers while reading the text.And then make them answer them.Who is Chuck Noland?

      Why did he land on a deserted island? How many years had he stay there? Is he alone? …………

      4.Finish the first two questions of post-reading on page 4.5.Divide the whole class into several groups to discuss Question 4 of post-reading on page 4 or hold a debate among them.(Divide them into four groups.Each group represents one view of points.)

      6.Explain the language points in the text one by one.At the same time, make them make up sentences using what they have learnt.Homework:

      a.Try to memorize the new words & expressions.b.Try to recite the third paragraph.c.Write a composition: words limits: 100

      If you were alone on an island, what would you do in order to survive? 7.Some knowledge points:

      a.In the movie Cast Away, Tom Hanks played a man named Chuck Noland.Cast: cast, cast.To throw sth.on purpose or with force.Cast sb.away: usually used in the passive voice.It means that leaving sb somewhere because of the wreck.Play: to act the role of sb.e.g.he is playing Hamlet on the stage

      b.Chuck is a businessman who is always so busy that he has little time for his friends.So +adjective / adv.+ that + a sentence 如此.…….以至于……..e.g.That shirt is so nice that I have to buy it even if I have to borrow some money from my friends.He did so well that he was praised by the boss.c.(phrase)a successful manager all over the world / country

      d.One day Chuck is on a flight across the Pacific Ocean when suddenly his plane crashes.“When” means “just at that time”.It is usually used in the following structures: a.be + prep.Phrase + when

      e.g.we were at work that afternoon when suddenly a fire broke out.b.be doing sth.+ when…

      e.g.we were having a meeting when someone broke in angrily.c.be about to do sth.+ when …..e.g.I was about to go out when someone knocked at the door.e.Chuck survives the crash and lands on a deserted island.Survive: continue to live or exist in spite of nearly being killed or destroyed.Survive an earthquake, accident, etc.幸存的人或物+survive+事故 / 事件

      e.g.the plants may not survive the frost.Deserted: with no one present.A deserted street, area, etc.Desert n.沙漠

      d.all alone: all by himself or it means that only by himself.e.He has to learn how to collect water, hunt for food, and make fire.f.challenge: N.invitation or call to take part in a game, contest, fight, etc.to prove who is better or stronger, etc.challenge(to sb)(to do sth.)to issue / accept a challenge.Challenge V.challenge sb(to sth.)e.g.challenge sb to a game of tennis.Challenging adj.具有挑戰(zhàn)性的,激勵(lì)的 e.g.a challenging job, test.g.In order to survive, Chuck develops a friendship with an unusual friend---a volleyball he calls Wilson.In order to do sth.means “ so as to” but “so as to” could not be used in a negative sentence.Develop a friendship with sb.h.He realizes that he hasn’t been a very good friend because he has always been thinking about himself.Realize(se): understand e.g.I realized that they had told the secret the others before they told it to us.Have / has been doing sth.現(xiàn)在完成進(jìn)行時(shí)

      Think about and think of:

      作“考慮”和“想起”解時(shí)兩者同意,可以互換使用。但是作“對(duì)……有看法”或“評(píng)價(jià)”時(shí)則只能使用think of.e.g.do you ever think about your childhood? What do you think of the film?

      i.even if is equal to even though.讓步狀語(yǔ)從句

      j.He talks to him and treats him as a friend.Treat…….as(pre.)…..e.g.I decided to treat his words as jokes.k.share happiness and sorrow share: to have or use sth.with others.share sth.(with sb.)e.g.there is only one bedroom, so we have to share.I mean I have to share the bedroom with you.Sorrow: great sadness

      l.it is important to have someone to care about it is +adj.+to / for sb to do something e.g.it is difficult for us to pass CET 4

      it is very kind of you to help me with my homework.m.Care about: be worried, concerned or interested.憂慮,關(guān)心,惦念

      e.g.People all over the world are caring about the future of Iraq.They don’t care about what will happen to the family.Care for:(一般用于疑問(wèn)句和否定句)喜歡或愛(ài)某人;照看,照顧某人;(否定句)對(duì)某人或某事物愛(ài)好或喜愛(ài)

      e.g.he cares for her deeply.Who will care for him if his wife dies? I don’t care much for opera.n.He also learns that he should have cared more about his friends.Should have cared: should have done, this is the subjunctive mood.It means that you should do something, but really you didn’t do that.o.We must give as much as we take.As + adj./ adv.+as + noun./ a sentence

      e.g.You should finish the work as early as possible.We will do the work as well as we can.Can you give me the apple as big as yours? p.human being: man, woman or child;person

      q.The lesson we can learn from Chuck and all the others who have unusual friends is that friends are teachers.此句的基本結(jié)構(gòu)是the lesson is……..that……..Who 引導(dǎo)的是定語(yǔ)從句修飾的是all the others, 但that 引導(dǎo)的是表語(yǔ)從句,在表語(yǔ)從句中必須使用陳述語(yǔ)序。

      e.g.the trouble is that I have lost his address.r.such as and for example: such as + noun.For example, +noun or sentence and the phrase for example can be used at the end of a sentence.e.g.many people, such as children and old men, lost their lives in the war.Many soldiers, for example, Lei Feng, have done very great deeds in their lives.s.friendship helps us understand who we are.help sb +to do / do sth.You may help me to finish the job.Period 5&6

      Language study& Practicing

      Teaching aims: Learn the rules of transformation of the Direct and Indirect Speeches and transform them fluently and correctly.How to carry it out: 1.Greetings to the Ss.2.Dictation of words & phrases.3.“Word study” on Page 4.Fill in and then translate them.4.“Vocabulary” on page 87 in WB.5.Give instructions on the translation work and do “Vocabulary 3”.Let the Ss.hand it in.Grammar Study

      當(dāng)我們引用別人的話時(shí)。如果我們引用別人的原話,那么被引用的部分就叫直接引語(yǔ),一般用“ ”引起來(lái)。如果我們用自己把意思轉(zhuǎn)述出來(lái),那么這樣的話稱(chēng)為間接引語(yǔ)。間接引語(yǔ)在多數(shù)情況下都構(gòu)成一個(gè)賓語(yǔ)從句。由直接引語(yǔ)轉(zhuǎn)化成間接引語(yǔ)可以分成下面幾種情況:

      1、如果直接引語(yǔ)是一個(gè)陳述句,在變成間接引語(yǔ)時(shí)一是要用連詞把主句和從句連接起來(lái),that可省略。二是根據(jù)意思改變?nèi)朔Q(chēng),三是直接引語(yǔ)的動(dòng)詞的時(shí)態(tài)要作相應(yīng)的變動(dòng)。四是根據(jù)意思將指示代詞、地點(diǎn)及時(shí)間狀語(yǔ)等作必要的變動(dòng)。

      ⑴Lin Tao said, “I am ready.” Lin Tao said(that)he was ready.⑵He said(to me), “I have left my book at home” He told me that he had left his book at home.⑶She said, “I will come here again tonight.” She said(that)she would come there again that night.2、在引用一個(gè)疑問(wèn)句時(shí),要用連詞whether或if連接起來(lái),不能省略。此外還要把人稱(chēng)、時(shí)態(tài),時(shí)間和地點(diǎn)狀語(yǔ)作相應(yīng)的變化,從句一定要用陳述語(yǔ)序。

      He asked, “Can you come here tomorrow.” He asked(me)if I could go there the next day.He asked, “ are you a teacher?” He asked me whether / if I was a teacher.3、如果直接引語(yǔ)是特殊疑問(wèn)句,那么特殊疑問(wèn)句作連詞,連詞不能省略,然后人稱(chēng)、時(shí)態(tài)、時(shí)間狀語(yǔ)等仍需適當(dāng)?shù)淖兓?,引語(yǔ)的語(yǔ)序?yàn)殛愂稣Z(yǔ)序。

      ⑴.He asked, “How are you getting along with your studies.” He said me how I was getting along with my studies.⑵.She asked, “Where will you have lunch ,Tom.” She asked Tom where he would have lunch.(3)She said, “ what are you doing?” She asked me what I was doing.時(shí)間改變可以用下表表示:

      直接引語(yǔ) 間接引語(yǔ)

      一般現(xiàn)在時(shí) 一般過(guò)去時(shí)

      現(xiàn)在進(jìn)行時(shí) 過(guò)去進(jìn)行時(shí)

      一般將來(lái)時(shí) 過(guò)去將來(lái)時(shí)

      一般過(guò)去時(shí) 過(guò)去完成時(shí)

      現(xiàn)在完成時(shí) 過(guò)去完成時(shí)

      過(guò)去完成時(shí) 過(guò)去完成時(shí)

      現(xiàn)在完成進(jìn)行時(shí) 過(guò)去完成進(jìn)行時(shí)

      注意:如果直接引語(yǔ)表達(dá)的是客觀事實(shí),或當(dāng)時(shí)直接轉(zhuǎn)述,時(shí)態(tài)不用變。如:

      The teacher told us that the earth turns around the sun.4、一些常用詞改變規(guī)律表:

      在直接引語(yǔ)中 在間接引語(yǔ)中

      指示代詞 This That These Those

      表時(shí)間的詞 Now Then Today that day

      This week(month ,etc)that week(month)Yesterday the day before

      Last week(month)The week(month etc)before Three days(a year, etc)ago three days(a year etc)before Tomorrow the next(following)day Next week(month)the next(following)week 地點(diǎn) Here There 動(dòng)詞 Come Go

      5、如果直接引語(yǔ)是祈使句,將say變?yōu)閍sk或tell等,直接在動(dòng)詞前加“to”。否定式加not to,這個(gè)請(qǐng)求或命令由一個(gè)復(fù)合賓語(yǔ)表示出來(lái)。

      He said, “Come in, please.” He asked me to come in.He said, “Don’t do that again ,Peter.” He told Peter not to do that again.Grammar exercises 1: Ask someone to answer.1.Do “Grammar” 1 on Page 5 in SB, paying enough attention to the students’ common errors.2.Do “Grammar” 1 on Page 87 in WB.3.Do “Grammar” 2 & 3 individually, in pairs, or in groups.Of course, this part can be assigned for the students’ homework.4.“Grammar” 2 on Page 5-6 in SB is optional.You may do it by way of pair work or group work, or even simply omit it.But in this part, I should emphasize some words and phrases: be angry with sb.miss sth / sb.reef: 焦,焦脈.not any longer=not any much take care of =look after I am scared.Homework:

      Finish Question 2 on page 87 after class.And check it next period.Period 7 & 8

      Integrating skills &Assessing

      Teaching aims: how to compose an E-mail How to carry it out: 1.Greetings to the Ss.2.Homework checkup/analysis Point out some common problems coming forth in Ss.’ homework.3.Reading and Writing on page 6 & 7 on the Ss.’ Book.Study the instruction and read the two quoted messages to decide whom of the two to make friends with.Pay special attention to the following words and phrases: e-pal, click it away, drop sb.line 4.“E-mail” writing formula To: Subject: Attachments: The body: Date Hi/Dear…… ……………… ……………… ……………… Your signature

      5.Get the Ss.finish writing on page 7 & 90.6.Finish “Reading” on page 88 & 89.7.Assessing

      Handouts for Ss.to self assess.Add some other items.Homework:

      1.Ask the Ss.to write an E-mail to me.2.Preview the new unit especial the new words.

      第二篇:高一物理牛頓第二定律教案1

      億庫(kù)教育網(wǎng)

      http://004km.cn 百萬(wàn)教學(xué)資源免費(fèi)下載

      第三章第三節(jié) 牛頓第二定律

      教學(xué)目的

      掌握牛頓第二定律相關(guān)知識(shí);

      了解控制變量法,培養(yǎng)學(xué)生動(dòng)手實(shí)驗(yàn)?zāi)芰头治龈爬ㄖR(shí)的能力。教學(xué)用具

      牛頓第二定律驗(yàn)證器、砝碼、多媒體課件 重點(diǎn)難點(diǎn)

      重點(diǎn):牛頓第二定律的知識(shí)及其應(yīng)用;難點(diǎn):實(shí)驗(yàn)演示的操作。教學(xué)過(guò)程

      一、復(fù)習(xí)引入:

      1、我們講了牛頓第一定律,它的內(nèi)容是什么呢?

      多媒體課件演示:一切物體總保持勻速直線運(yùn)動(dòng)狀態(tài)或靜止?fàn)顟B(tài),直到有外力迫使它改變這種狀態(tài)為止。也就是說(shuō),沒(méi)有外力作用時(shí),物體保持原來(lái)的狀態(tài),靜止的保持靜止、運(yùn)動(dòng)的保持勻速運(yùn)動(dòng)。那如果有外力作用呢?

      (引導(dǎo)回答)有外力作用----狀態(tài)改變----速度改變----有加速度產(chǎn)生。

      在上節(jié)課中我們還講了:質(zhì)量是物體慣性大小的量度,質(zhì)量越大的,狀態(tài)越難改變。這就涉及到三個(gè)物理量:力、加速度和質(zhì)量,三者之間到底有何關(guān)系呢?我們這節(jié)課就來(lái)研究它。

      二、進(jìn)行新課

      1、實(shí)驗(yàn)介紹

      實(shí)驗(yàn)是我們掌握物理知識(shí)的一個(gè)重要途徑,今天就利用實(shí)驗(yàn)來(lái)幫助我們解決這個(gè)問(wèn)題。F、m、a三者都是變量,在研究此類(lèi)問(wèn)題時(shí),我們先使其中一個(gè)量保持不變,來(lái)研究另外兩個(gè)量的關(guān)系,這就是控制變量法。

      (1)原理:F可以用彈簧秤測(cè)量,m可以用天平測(cè)量,那加速度呢? a=(S2-S1)/T2 測(cè)量加速度的方法: a=(Vt-V0)/t2 S= V0t+at2/2------------S= at2/2------------a=2S/t2(2)設(shè)計(jì)

      在光滑的導(dǎo)軌上放一量小車(chē),一端系有細(xì)繩,繞過(guò)定滑輪后吊著砝碼,砝碼質(zhì)量遠(yuǎn)小于小車(chē)質(zhì)量。

      受到恒力作用的小車(chē)做勻速直線運(yùn)動(dòng),有S= V0t+at2/2----S= at2/2------a=2S/t2,為了便于比較,我們?nèi)蓚€(gè)小車(chē)做雙軌實(shí)驗(yàn)。當(dāng)時(shí)間t相同時(shí),有a1/a2=S1/S2。(3)實(shí)驗(yàn)操作(1)

      億庫(kù)教育網(wǎng)

      http://004km.cn 百萬(wàn)教學(xué)資源免費(fèi)下載 億庫(kù)教育網(wǎng)

      http://004km.cn 百萬(wàn)教學(xué)資源免費(fèi)下載

      平衡摩擦力;將兩輛質(zhì)量相同的小車(chē)放在導(dǎo)軌上;系上細(xì)繩,跨過(guò)定滑輪掛上質(zhì)量不同的砝碼;利用控制桿控制兩輛小車(chē)同時(shí)運(yùn)動(dòng);記錄數(shù)據(jù)。(4)實(shí)驗(yàn)操作(2)

      將兩輛質(zhì)量不同的小車(chē)放在導(dǎo)軌上;系上細(xì)繩,跨過(guò)定滑輪掛上質(zhì)量相同的砝碼。利用控制桿控制兩輛小車(chē)同時(shí)運(yùn)動(dòng);記錄數(shù)據(jù)。

      2、實(shí)驗(yàn)結(jié)論

      m一定時(shí),F(xiàn)與a成正比;F一定時(shí),m與a成反比。

      3、牛頓第二定律

      內(nèi)容:物體的加速度與力成正比,與質(zhì)量成反比。公式:F=Kma;注:取國(guó)際單位時(shí),K等于1。

      平衡摩擦力分析(導(dǎo)出)牛頓第二定律更一般的表述:物體的加速度與合外力成正比,與質(zhì)量成反比,加速度的方向與外力的方向相同。

      三、本節(jié)小結(jié)

      四、例題示范和課堂練習(xí)(學(xué)生討論,老師引導(dǎo))(1)下列說(shuō)法中正確的是:

      (A)物體的加速度與質(zhì)量成反比,與合外力成正比。(B)物體的加速度方向與合外力保持一致。(C)在公式F=Kma中,K始終等于1。(D)將軌道稍稍?xún)A斜是為了平衡摩擦力。

      (2)一列火車(chē)由靜止開(kāi)始駛離車(chē)站已知其質(zhì)量是100T,為了產(chǎn)生2m/S2的加速度,車(chē)頭的牽引力應(yīng)為多大?

      (3)一個(gè)物體,質(zhì)量是2Kg,受到互成120度角的兩個(gè)力F1和F2的作用,兩個(gè)力的大小都為10N,這個(gè)物體產(chǎn)生的加速度是多大?

      (4)一個(gè)質(zhì)量m=2kg的物體,在一個(gè)恒力的作用下從靜止開(kāi)始向右勻加速運(yùn)動(dòng)。已知恒力F=6牛,12、問(wèn)這個(gè)物體2秒末的速度及位移各是多少?

      四、課后作業(yè)(略)

      億庫(kù)教育網(wǎng)

      http://004km.cn 百萬(wàn)教學(xué)資源免費(fèi)下載

      第三篇:高一物理功率教案1

      3eud教育網(wǎng) http://www.3edu.net 百萬(wàn)教學(xué)資源,完全免費(fèi),無(wú)須注冊(cè),天天更新!

      功率

      (一)引入課題

      首先以提問(wèn)方式復(fù)習(xí)上一節(jié)所學(xué)習(xí)的主要內(nèi)容,重點(diǎn)是功的概念和功的物理意義.

      然后提出力對(duì)物體做功的實(shí)際問(wèn)題中,有做功快慢之分,物理學(xué)中又是如何來(lái)描述的?這節(jié)課我們就來(lái)研究這個(gè)問(wèn)題.

      (二)教學(xué)過(guò)程

      1、功率

      初中同學(xué)們學(xué)習(xí)過(guò)功率的有關(guān)知識(shí),都知道功率是用來(lái)描述力做功快慢的物理量.我們一起討論一些問(wèn)題.

      力F1對(duì)甲物體做功為W1,所用時(shí)間為t1;力F2對(duì)乙物體做功為W2,所用時(shí)間為t2,在下列條件下,哪個(gè)力做功快?

      A.W1=W2,t1>t2; B.W1=W2,t1<t2;

      C.W1>W(wǎng)2,t1=t2; D.W1<W2,t1=t2.

      上述條件下,哪個(gè)力做功快的問(wèn)題學(xué)生都能作出判斷,其實(shí)都是根據(jù)W/t這一比值進(jìn)行分析判斷的.讓學(xué)生把這個(gè)意思說(shuō)出來(lái),然后總結(jié)并板書(shū)如下: 功率是描述做功快慢的物理量.

      功和完成這些功所用的時(shí)間之比,叫做功率.如果用W表示功,t表示完成這些功所用的時(shí)間,P表示功率,則:

      P=W/t

      明確告訴學(xué)生上式即為功率的定義式,然后說(shuō)明P的單位,W用J、t用s作單位,P的單位為J/s,稱(chēng)為瓦特,符號(hào)為W.最后分析并說(shuō)明功率是標(biāo)量.

      接下來(lái)著重說(shuō)明,功率的大小與單位時(shí)間內(nèi)力所做的功為等值.

      至此,再將功的定義式與速度v的定義式作類(lèi)比,使學(xué)生理解,雖然研究的是不同性質(zhì)的問(wèn)題,但是研究方法是相同的(同時(shí)也為后面講瞬時(shí)功率做了些準(zhǔn)備).然后提出問(wèn)題,與學(xué)生一起討論功率的物理意義.

      上一節(jié)我們講了功的概念、功的公式之后,經(jīng)過(guò)分析和討論,對(duì)功的物理意義已有所了解.誰(shuí)能復(fù)述一下?

      在學(xué)生說(shuō)出做功過(guò)程是能量轉(zhuǎn)化過(guò)程之后,立即啟發(fā):那么做功快慢恰能表明能量轉(zhuǎn)化的快慢嗎?因此,應(yīng)該將功率理解為是描述做功過(guò)程中能量轉(zhuǎn)化快慢的物理量,并將這一認(rèn)識(shí)進(jìn)行板書(shū).

      2、平均功率與瞬時(shí)功率

      舉例:一個(gè)質(zhì)量是1.0kg的物體,從地面上方20m高處開(kāi)始做自由落體運(yùn)動(dòng),第1s時(shí)間內(nèi)下落的位移是多少?(與學(xué)生一塊算出是5m,g取10m/s2)這1s內(nèi)重力對(duì)物體做多少功?(與學(xué)生一起算出W1=50J)第2s時(shí)間內(nèi)物體下落的位移是多少?(15m)這1s內(nèi)重力對(duì)物體做多少功?(W2=150J)前1s和后1s重力對(duì)物體做功的功率各是多大?(P1=50W,P2=150W)這2s時(shí)間內(nèi)重力對(duì)物體做功的功率是多大?(P=100W)

      指出即使是同一個(gè)力對(duì)物體做功,在不同時(shí)間內(nèi)做功的功率也可能是有變化的.因而,用P=W/t求得的功率只能反映t時(shí)間內(nèi)做功的快慢,只具有平均的意義.板書(shū)如下:(1)平均功率:

      P=W/t(2)瞬時(shí)功率

      為了比較細(xì)致地表示出每時(shí)每刻的做功快慢,引入了瞬時(shí)功率的概念,即瞬時(shí)功率是表示某個(gè)瞬時(shí)做功快慢的物理量.

      提出瞬時(shí)功率如何計(jì)算的問(wèn)題后,作如下推導(dǎo):

      一段較短時(shí)間內(nèi)的平均功率可以寫(xiě)成如下公式:

      P=W/t=W = F·s/ t,而s/t=v

      所以:P= F·v

      當(dāng)t值足夠小時(shí),v就表示某一時(shí)刻的瞬時(shí)速度,所以這時(shí)P就表示該時(shí)刻的瞬時(shí)功率.

      因此 P=F·v 就是瞬時(shí)功率計(jì)算公式

      討論:

      ①如果作用于物體上的力F為恒力,且物體以速度v勻速運(yùn)動(dòng),則力對(duì)物體做功的功率保持不變.此3eud教育網(wǎng) http://www.3edu.net 教學(xué)資源集散地??赡苁亲畲蟮拿赓M(fèi)教育資源網(wǎng)!3eud教育網(wǎng) http://www.3edu.net 百萬(wàn)教學(xué)資源,完全免費(fèi),無(wú)須注冊(cè),天天更新!

      情況下,任意一段時(shí)間內(nèi)的平均功率與任一瞬時(shí)的瞬時(shí)功率都是相同的.

      ②很多動(dòng)力機(jī)器通常有一個(gè)額定功率,且通常使其在額定功率狀態(tài)工作(如汽車(chē)),根據(jù)P=Fv可知:

      當(dāng)路面阻力較小時(shí),牽引力F也小,v可以大,即汽車(chē)可以跑得快些;

      當(dāng)路面阻力較大,或爬坡時(shí),需要比較大的牽引力,v必須?。@就是爬坡時(shí)汽車(chē)換低速擋的道理.

      ③如果動(dòng)力機(jī)器原來(lái)在遠(yuǎn)小于額定功率的條件下工作,例如汽車(chē)剛剛起動(dòng)后的一段時(shí)間內(nèi),速度逐漸增大過(guò)程中,牽引力仍可增大,即F和v可以同時(shí)增大,但是這一情況應(yīng)以二者乘積等于額定功率為限度,即當(dāng)Fv=P額.以后,這種情況不可能實(shí)現(xiàn).

      應(yīng)用公式P=Fv計(jì)算m=1kg的物體做自由落體運(yùn)動(dòng)中下落1s末和2s末的瞬時(shí)功率.

      由v1=10m/s按公式求得P1=100J;由v2=20m/s按公式求得P2=200J.

      根據(jù)上述結(jié)果啟發(fā)學(xué)生思考瞬時(shí)功率的物理意義.最后指出,此題中是重力對(duì)物體做功,使重力勢(shì)能逐漸向動(dòng)能轉(zhuǎn)化.隨著時(shí)間的延續(xù),重力勢(shì)能向動(dòng)能轉(zhuǎn)化加快.

      3、例題講解

      1、如圖1所示,位于水平面上的物體A的質(zhì)量m=5kg,在F=10N的水平拉力作用下從靜止開(kāi)始向右運(yùn)動(dòng),位移為s=36m時(shí)撤去拉力F.求:在下述兩種條件下,力F對(duì)物體做功的平均功率各是多大?(取g=10m/s2)

      (1)設(shè)水平面光滑;

      (2)設(shè)物體與水平面間的動(dòng)摩擦因數(shù)μ=0.15.

      解答過(guò)程可分為三個(gè)階段:

      ①讓學(xué)生計(jì)算力F在36m位移中所做的功,強(qiáng)調(diào)功只由F和s這兩個(gè)要素決定,與其它因素?zé)o關(guān),因而兩種情況下力F做的功相同,均為W=360J.

      ②由同學(xué)計(jì)算這兩次做功所用的時(shí)間.用牛頓第二定律求出:

      分別求出t1=6s,t2=12s.

      ③用功率的定義式即平均功率的計(jì)算公式求得P1=60W,P2=30W.

      如果有的同學(xué)用公式vt2=2αs分別求出每次的末速度,再用公式:

      和,最后用 求得最后結(jié)果也可以,并指出這是 求出每次的平均速度 解決問(wèn)題的一另一思路。

      2、如圖2所示,位于水平面上的物體A,在斜向上的恒定拉力作用下,正以v=2m/s的速度向右做勻速直線運(yùn)動(dòng).已知F的大小為100N,方向與速度v的夾角為37°,求:

      (1)拉力F對(duì)物體做功的功率是多大?

      (2)物體向右運(yùn)動(dòng)10s的過(guò)程中,拉力F對(duì)它做多少功?(sin37°=0.6,cos37°=0.8)

      通過(guò)此例題的解答,讓學(xué)生掌握功率的計(jì)算公式P=Fvcosα,并提醒學(xué)生,不要認(rèn)為F與v總是在同一直線上;并且知道,在功率已知的條件下,可以用W=P·t計(jì)算一段時(shí)間內(nèi)力所做的功.第(1)問(wèn)的結(jié)果為P=160W;第(2)問(wèn)的結(jié)果為W=1600J.

      3、課本p.139上的例題,注意區(qū)分幾個(gè)概念.

      (三)課堂小結(jié)

      1、我們講了功率概念之后,得到了兩個(gè)公式,定義式P=W/t和瞬時(shí)功率的公式P=F·v.

      2、公式P=W/t中的t趨近于零時(shí),P即為瞬時(shí)功率.不過(guò)此公式主要用來(lái)計(jì)算平均功率.公式P=Fv中,當(dāng)v為瞬時(shí)速度時(shí),P即為瞬時(shí)功率;當(dāng)v用平均速度

      時(shí),也可計(jì)算平均功率.當(dāng)然要注意 所對(duì)應(yīng)的時(shí)間段.

      說(shuō)明:

      1、將功率理解為表示能量轉(zhuǎn)化快慢的物理量具有普遍意義.如一臺(tái)電動(dòng)機(jī)的額定功率是10kW,表明它每秒鐘可以將10kJ的電能轉(zhuǎn)化為機(jī)械能,不管它是否工作.因而機(jī)器的功率實(shí)際上可以表示它進(jìn)行能量轉(zhuǎn)化的能力大小.

      2、力可以做負(fù)功,自然也有負(fù)功率.學(xué)生不問(wèn)到時(shí)可以不講.課本上也沒(méi)講.重要的不是功率的3eud教育網(wǎng) http://www.3edu.net 教學(xué)資源集散地??赡苁亲畲蟮拿赓M(fèi)教育資源網(wǎng)!3eud教育網(wǎng) http://www.3edu.net 百萬(wàn)教學(xué)資源,完全免費(fèi),無(wú)須注冊(cè),天天更新!

      正負(fù)問(wèn)題,而是要結(jié)合實(shí)際問(wèn)題說(shuō)清楚能量轉(zhuǎn)化的方向和快慢.例如,一物體沿粗糙水平面向前滑動(dòng),根據(jù)P=f·v可知其機(jī)械能向內(nèi)能轉(zhuǎn)化,轉(zhuǎn)化的快慢與速度v成正比,這就表達(dá)清楚了,沒(méi)有強(qiáng)調(diào)負(fù)功率的必要

      擴(kuò)展資料 額定功率與實(shí)際功率

      額定功率是發(fā)動(dòng)機(jī)正常工作時(shí)的最大功率,通常都在銘牌上標(biāo)明,機(jī)器工作時(shí),必須受額定功率的限制,這是基本原則,發(fā)動(dòng)機(jī)實(shí)際的輸出功率(即實(shí)際功率),可以小于額定功率,在某些情況下,實(shí)際功率也可以略大于額定功率,但不允許長(zhǎng)時(shí)間超過(guò)額定功率.

      關(guān)于汽車(chē)啟動(dòng)的運(yùn)動(dòng)過(guò)程分析

      1、下面我們來(lái)討論汽車(chē)起動(dòng)的模型:(1)以恒定功率起動(dòng),其運(yùn)動(dòng)過(guò)程是:

      2、以恒定加速度起動(dòng),其運(yùn)動(dòng)過(guò)程是:

      3eud教育網(wǎng) http://www.3edu.net 教學(xué)資源集散地??赡苁亲畲蟮拿赓M(fèi)教育資源網(wǎng)!3eud教育網(wǎng) http://www.3edu.net 百萬(wàn)教學(xué)資源,完全免費(fèi),無(wú)須注冊(cè),天天更新!

      機(jī)車(chē)啟動(dòng)的兩種過(guò)程

      1、以恒定的功率起動(dòng):

      機(jī)車(chē)以恒定的功率起動(dòng)后,若運(yùn)動(dòng)過(guò)程中所受阻力f不變,由于牽引力,隨v增大,F(xiàn)減?。鶕?jù)牛頓第二定律,是做加速度減小的加速運(yùn)動(dòng).直至,當(dāng)速度v增大時(shí),加速度a減小,其運(yùn)動(dòng)情況

      時(shí),a減小至零,此后速度不再增大,速度達(dá)到最大值而做勻速運(yùn)動(dòng),做勻速直線運(yùn)動(dòng)的速度是,下面是這個(gè)動(dòng)態(tài)過(guò)程的簡(jiǎn)單方框圖

      這一過(guò)程的v-t關(guān)系如圖所示.

      2、車(chē)以恒定的加速度a起動(dòng).

      由 知,當(dāng)加速度a不變時(shí),發(fā)動(dòng)機(jī)牽引力F恒定,再由 知,F(xiàn)一定,發(fā)動(dòng)機(jī)實(shí)際輸出功率P隨v的增大而增大,但當(dāng)P增大到額定功率以后不再增大,此后,發(fā)動(dòng)機(jī)保持額定3eud教育網(wǎng) http://www.3edu.net 教學(xué)資源集散地??赡苁亲畲蟮拿赓M(fèi)教育資源網(wǎng)!3eud教育網(wǎng) http://www.3edu.net 百萬(wàn)教學(xué)資源,完全免費(fèi),無(wú)須注冊(cè),天天更新!

      功率不變,v繼續(xù)增大,牽引力F減小,直至 后勻速運(yùn)動(dòng).

      在P增至

      時(shí),車(chē)速達(dá)到最大值,此之前,車(chē)勻加速運(yùn)動(dòng),其持續(xù)時(shí)間為

      (這個(gè) 必定小于,它是車(chē)的功率增至

      之時(shí)的瞬時(shí)速度).計(jì)算時(shí),先算出F;,再求出

      在P增至 圖,最后根據(jù) 求t.

      .下面是這個(gè)動(dòng)態(tài)過(guò)程的簡(jiǎn)單方框之后,為加速度減小的加速運(yùn)動(dòng).直至達(dá)到

      這一過(guò)程的v-t關(guān)系如圖所示。

      習(xí)題精選

      (一)1.質(zhì)量為m的物體自高處自由落下,時(shí)間t內(nèi)重力的平均功率為_(kāi)____,t秒末重力的瞬時(shí)功率為_(kāi)____.2.設(shè)飛機(jī)飛行時(shí)所受的阻力與其速度的平方成正比.如果飛機(jī)以速度v勻速飛行時(shí)其發(fā)動(dòng)機(jī)的功率為P,則飛機(jī)以2v的速度勻速飛行時(shí)其發(fā)動(dòng)機(jī)的功率為_(kāi)____.3.起重機(jī)的鋼繩吊著物體由靜止開(kāi)始豎直向上運(yùn)動(dòng),先以加速度a(a<g)加速運(yùn)動(dòng)再勻速運(yùn)動(dòng),最后減速運(yùn)動(dòng)到靜止,則關(guān)于各段運(yùn)動(dòng)中繩的拉力的平均功率,下列說(shuō)法中正確的是

      A.第一段平均功率最大 B.第二段平均功率最大

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      C.第三段平均功率最小 D.第一段平均功率最小

      4.跳繩是一種健身運(yùn)動(dòng),設(shè)某運(yùn)動(dòng)員的質(zhì)量是50 kg,他1分鐘跳180次,假定在每次跳躍中,腳與地面的接觸時(shí)間占跳躍一次所需時(shí)間的,則該運(yùn)動(dòng)員跳繩時(shí)克服重力做功的平均功率是多少瓦?(g取10 m/s2)

      5.站在自動(dòng)扶梯上的乘客,如果他自己也沿著扶梯勻速上行.那么在運(yùn)送乘客到達(dá)同樣高度時(shí),自動(dòng)扶梯的發(fā)動(dòng)機(jī)所消耗的功和功率的情況是

      A.功增加,功率不變 B.功減少,功率不變

      C.功不變,功率增加 D.功不變,功率減少

      E.功和功率都不變 F.功和功率都減少

      6.在20 m高處以大小相等的初速度v0=20 m/s將三個(gè)質(zhì)量均為0.1 kg的小球a、b、c分別豎直上拋、平拋和自由落下,從拋出到落地的全過(guò)程中,求重力對(duì)三球做的功和平均功率(不計(jì)空氣阻力,g=10 m/s2) 參考答案:

      1.2.8P

      3.BC4.75 W5.B6.20 J、20 J、20 J10((二))W,10 W,10 W

      1.如圖所示,在豎直向上加速運(yùn)動(dòng)的電梯中有一個(gè)斜面,斜面上有一個(gè)木塊與斜面一起隨電梯向上加速運(yùn)動(dòng),木塊相對(duì)斜面靜止.試分析木塊受到力做功情況.

      2.有一物體受一水平力作用,第一次在光滑的水平面上前進(jìn)了 位移,第二次在粗糙的水平面上前進(jìn)了 位移,試比較兩次F做功情況.

      3.斜面體A放在光滑的水平面上,滑塊B沿斜面加速下滑,如圖所示,試分析 滑塊B所受各力在滑塊B下滑過(guò)程中的做功情況.

      4.質(zhì)量為m的木塊,在水平恒力F作用下從靜止開(kāi)始沿光滑的水平面運(yùn)動(dòng) 時(shí)間,則在 s末的功率為,在整個(gè) 時(shí)間內(nèi)F做功的平均功率為 .

      5.汽車(chē)發(fā)動(dòng)機(jī)的額定功率為60,汽車(chē)的質(zhì)量為,它與地面的動(dòng)磨擦因數(shù)為 則:

      (l)汽車(chē)保持額定功率起動(dòng)后能達(dá)到的最大速度是多少?

      (2)汽車(chē)從靜止開(kāi)始以)

      6.如圖所示,質(zhì)量為 的物體從光滑的斜面頂端自由下滑,斜面高為,長(zhǎng)為,求在從頂端滑至底端的過(guò)程中,受到的力所做功及它們的沖量.

      7.一光滑小球沿半圓形圓槽從槽口由靜止沿槽滾至槽底所用時(shí)間為t,速度為,則此過(guò)程中().

      (A)槽對(duì)小球的支持力沖量為零(B)槽對(duì)小球的支持力做功為零

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      (C)槽對(duì)小球的沖量為m

      (D)小球所受合外力沖量為m

      8.在水平的船板上有一人拉著固定在岸邊樹(shù)上的繩子,用力使船向前移動(dòng)(如圖),關(guān)于什么力對(duì)船做功的下列說(shuō)法中正確的是()

      A.繩的拉力做了功

      B.人對(duì)繩的拉力做了功

      C.樹(shù)對(duì)繩子的拉力做了功

      D.人對(duì)船的靜摩擦做了功

      9.一質(zhì)量為 的木塊靜止在光滑的水平面上,從

      開(kāi)始,將一個(gè)大小為 F的水平恒力作用在該木塊上,在()

      時(shí)刻F的功率是

      A. B. C. D.

      10.汽車(chē)額定功率為 定功率,汽車(chē)行駛中受到的阻力 隨速度的增大而增大,假如汽車(chē)始終都在額下工作,那么汽車(chē)所能達(dá)到的最大速度是多少(如圖所示)

      【參考答案】

      1.解答分析木塊受力情況.因?yàn)槟緣K加速向上運(yùn)動(dòng),所以其受力圖如圖,重力G與位移方向相反,重力做負(fù)功;支持力N與位移方向的夾角為銳角,支持力做正功;靜摩擦力f與位移方向的夾角也為銳角,則靜摩擦力做正功.

      2.因?yàn)?,F(xiàn),一定,故兩次力F做功相同.

      為B 3.提示 畫(huà)出A、B的始末位置,分析兩物的位移,注意B的對(duì)地位移 相對(duì)A的位移 位移 與A相對(duì)地的位移 的合成(如圖),找出各力與B的對(duì)地的夾角即可判斷各力的做功情況.

      來(lái)求: 4.解答 時(shí)間末的功率為瞬時(shí)功率,用

      時(shí)間內(nèi)平均功率用 來(lái)求:

      時(shí),汽車(chē)的速度最大,此時(shí):

      ,5.解答(1)汽車(chē)以額定功率起動(dòng),當(dāng)

      所以最大速度

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      (2)汽車(chē)以勻加速直線運(yùn)動(dòng)起動(dòng),汽車(chē)在勻加速運(yùn)動(dòng)過(guò)程中的最大速度

      根據(jù)牛頓第二定律

      由① ②得:

      勻加速直線運(yùn)動(dòng)過(guò)程維持的時(shí)間

      6.解答 受到豎直向下的重力

      和垂直于斜面斜向上的彈力N,如圖所示,先求斜面下滑的時(shí)間:

      ,,重力所做的功: .

      重力的沖量:

      方向豎直向下.

      彈力所做的功: .,彈力的沖量:

      沖量方向沿垂直斜面方向向上.

      7.解答 正確答案為(B)、(D).

      8.解析 繩的拉力、人對(duì)繩的拉力和樹(shù)對(duì)繩子的拉力并沒(méi)有作用于船,沒(méi)有對(duì)船做功.只有人對(duì)船的靜摩擦力作用于船,且船發(fā)生了位移,故對(duì)船做了功,且做正功.設(shè)想一下若船板光滑,人與船之間無(wú)摩擦力,則人拉繩時(shí),人前進(jìn)了,船則在原處不動(dòng),沒(méi)有力對(duì)船做功.

      9.解析 此題不少同學(xué)選C,原因是將

      時(shí)刻的功率錯(cuò)誤的理解為T(mén)這段時(shí)間內(nèi)的平均功率,從而用 求得C答案.因此出現(xiàn)了錯(cuò)誤.T時(shí)刻的功率為瞬時(shí)功率,只能用 求解.

      因?yàn)槲矬w加速度,T時(shí)刻速度

      所以,故選項(xiàng)B正確.

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      10.解 開(kāi)始起動(dòng)時(shí).車(chē)速較小,由 汽車(chē)所受的合外力

      得,F(xiàn)牽引力很大,由于

      小所以阻力

      也小,比較大,汽車(chē)的加速度較大;隨著汽車(chē)速度的增大,阻力也在多大,牽引力在減小,但只要 那么汽車(chē)所受的合外力就不為零,汽車(chē)就有加速度,汽車(chē)的速度就變大,所以汽車(chē)做的是加速度逐漸減小的變加速運(yùn)動(dòng),當(dāng)速度增大到某一個(gè)值時(shí),牽引力F減小到某一個(gè)值,阻力增大到某一個(gè)值,這時(shí)如果 加速度

      ,速度,那么,加速度為零,則牽引力,阻力,都是確定的值,不再發(fā)生變化,這時(shí)速度的值為最大值,用公式表示為:

      在通常計(jì)算中,一般假設(shè)阻力恒定不變,那么上述結(jié)論對(duì)這種情況一樣成立.

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      第四篇:高一英語(yǔ)europe教案1

      必修3 模塊一 grammar學(xué)案

      語(yǔ)法專(zhuān)練 [被動(dòng)語(yǔ)態(tài)] 1.The students ________ often ________(tell)to take care of their desks and chairs.2.Vegetables,eggs and fruits ________ ________(sell)in this shop.3.What ________ a knife ________(make)of? 4.A piano concert________ ________(give)here last Friday.5.These kinds of machines ________ ________(make)in Japan.6.Apples ________ ________(grow)in this farm.7.Russian ________ ________(learn)as the second language by some students in China.8.Planes,cars and trains ________ ________(use)by business people for traveling.9.The cinema ________ ________(build)in 1985.10.Tom ________ ________(not have)breakfast yesterday morning.[主謂一致] 1.About 60 percent of the students ________ from the south,the rest of them ________ from the north and foreign countries.A.are;is B.are;are

      C.is;are

      D.is;is 2.Half of the workers here ________ under 30 ________.A.is;years B.are;year old C.is;years old

      D.are;years of age 3.Now Tom with his classmates ________ football on the playground.A.play B.are playing

      C.plays

      D.is playing 4.The number of pages in this dictionary ________ about two thousand.A.are B.has

      C.have

      D.is 5.Thirty dollars ________ too expensive.A.are B.is

      C.were

      D.be 6.The secretary and principal ________ at the meeting now.A.are speaking

      B.is speaking D.have a speech C.were making a speech 7.“If anybody ________,please put down ________ name,”said the teacher to the monitor.A.wants to buy the book;his C.will buy the book;one’s

      B.want to buy the book;their D.wants to have the book bought;her 8.Nothing but one desk and six chairs ________ in the room.A.are

      B.is stayed

      C.is

      D.are left 9.Between the two roads ________ a TV tower called“Skyscraper Tower”.A.stands

      B.standing

      C.which stands

      D.stand 10.Either of you ________ going there tonight.A.will

      B.was

      C.is

      D.are 11.You as well ________ right.A.I are

      B.I am

      C.as I am

      D.as I are 12.All but Dick ________ in Class Three this term.A.are

      B.is

      C.were

      D.was 13.Where to get the materials and how to get them ________ at the meeting.A.have not discussed C.has not discussed

      B.have not been discussed D.has not been discussed 14.I took mathematics and physics because I think that ________ very important for me to make further research in this field.A.what is B.they are

      C.this

      D.which are 15.Every student and every teacher ________.A.are going to attend the meeting C.has attended the meeting.語(yǔ)法專(zhuān)練 被動(dòng)語(yǔ)態(tài):

      歸納:一般現(xiàn)在時(shí)和一般過(guò)去時(shí)的被動(dòng)語(yǔ)態(tài):

      被動(dòng)語(yǔ)態(tài)各時(shí)態(tài)的形式是由助動(dòng)詞be的各時(shí)態(tài)的形式加及物動(dòng)詞的過(guò)去分詞構(gòu)成的。一般現(xiàn)在時(shí):am/is /are+done 一般過(guò)去時(shí):was/were+done 1.答案:are,told 2.答案:are sold 3.答案:is,made

      B.have attended the meeting D.is attended the meeting 4.答案:was given 5.答案:are made 6.答案:are grown 7.答案:is learned 8.答案:are used 9.答案:was built 10.答案:didn’t have 主謂一致:

      1.解析:分?jǐn)?shù)和rest作主語(yǔ),謂語(yǔ)的數(shù)應(yīng)與它們后面的中心名詞保持一致。答案:B 2.解析:half作主語(yǔ)時(shí),謂語(yǔ)要與half后面的名詞保持一致。workers是復(fù)數(shù),謂語(yǔ)也要用復(fù)數(shù)。

      答案:D 3.解析:Tom是主語(yǔ),with...是狀語(yǔ)。答案:D 4.解析:the number作主語(yǔ),謂語(yǔ)用單數(shù)。答案:D 5.解析:度、量、衡作主語(yǔ),把它作為一個(gè)整體看待,視為單數(shù)。答案:B 6.解析:the secretary and principal 只有一個(gè)冠詞,一身兼兩職:是書(shū)記也是校長(zhǎng)。答案:B 7.解析:anybody作主語(yǔ),謂語(yǔ)是單數(shù);泛指一個(gè)人(的)一般用he(his)。答案:A 8.解析:nothing作主語(yǔ),謂語(yǔ)用單數(shù)。答案:C 9.解析:主語(yǔ)是a TV tower。這是一個(gè)完全倒裝結(jié)構(gòu)。答案:A 10.解析:either作主語(yǔ),謂語(yǔ)用單數(shù)。答案:C 11.解析:主語(yǔ)是you。as well as I(不僅是我)是狀語(yǔ)。答案:D 12.解析:All是主語(yǔ),它在這兒指人,所以應(yīng)是復(fù)數(shù)。答案:A 13.解析:兩個(gè)不定式的動(dòng)詞相同,屬于同一概念,所以謂語(yǔ)仍然用單數(shù)。答案:D 14.解析:they代替“mathematics and physics”。答案:B 15.解析:every+n.and every+n.屬于同一概念。

      第五篇:高一物理功率教案1

      高一物理功率教案1

      功率

      (一)引入課題

      首先以提問(wèn)方式復(fù)習(xí)上一節(jié)所學(xué)習(xí)的主要內(nèi)容,重點(diǎn)是功的概念和功的物理意義.

      然后提出力對(duì)物體做功的實(shí)際問(wèn)題中,有做功快慢之分,物理學(xué)中又是如何來(lái)描述的?這節(jié)課我們就來(lái)研究這個(gè)問(wèn)題.

      (二)教學(xué)過(guò)程

      1、功率

      初中同學(xué)們學(xué)習(xí)過(guò)功率的有關(guān)知識(shí),都知道功率是用來(lái)描述力做功快慢的物理量.我們一起討論一些問(wèn)題.

      力F1對(duì)甲物體做功為W1,所用時(shí)間為t1;力F2對(duì)乙物體做功為W2,所用時(shí)間為t2,在下列條件下,哪個(gè)力做功快?

      A.W1=W2,t1>t2; B.W1=W2,t1<t2; C.W1>W(wǎng)2,t1=t2; D.W1<W2,t1=t2.

      上述條件下,哪個(gè)力做功快的問(wèn)題學(xué)生都能作出判斷,其實(shí)都是根據(jù)W/t這一比值進(jìn)行分析判斷的.讓學(xué)生把這個(gè)意思說(shuō)出來(lái),然后總結(jié)并板書(shū)如下: 功率是描述做功快慢的物理量.

      功和完成這些功所用的時(shí)間之比,叫做功率.如果用W表示功,t表示完成這些功所用的時(shí)間,P表示功率,則: P=W/t 明確告訴學(xué)生上式即為功率的定義式,然后說(shuō)明P的單位,W用J、t用s作單位,P的單位為J/s,稱(chēng)為瓦特,符號(hào)為W.最后分析并說(shuō)明功率是標(biāo)量.

      接下來(lái)著重說(shuō)明,功率的大小與單位時(shí)間內(nèi)力所做的功為等值.

      至此,再將功的定義式與速度v的定義式作類(lèi)比,使學(xué)生理解,雖然研究的是不同性質(zhì)的問(wèn)題,但是研究方法是相同的(同時(shí)也為后面講瞬時(shí)功率做了些準(zhǔn)備).然后提出問(wèn)題,與學(xué)生一起討論功率的物理意義.

      上一節(jié)我們講了功的概念、功的公式之后,經(jīng)過(guò)分析和討論,對(duì)功的物理意義已有所了解.誰(shuí)能復(fù)述一下? 在學(xué)生說(shuō)出做功過(guò)程是能量轉(zhuǎn)化過(guò)程之后,立即啟發(fā):那么做功快慢恰能表明能量轉(zhuǎn)化的快慢嗎?因此,應(yīng)該將功率理解為是描述做功過(guò)程中能量轉(zhuǎn)化快慢的物理量,并將這一認(rèn)識(shí)進(jìn)行板書(shū).

      2、平均功率與瞬時(shí)功率

      舉例:一個(gè)質(zhì)量是1.0kg的物體,從地面上方20m高處開(kāi)始做自由落體運(yùn)動(dòng),第1s時(shí)間內(nèi)下落的位移是多少?(與學(xué)生一塊算出是5m,g取10m/s2)這1s內(nèi)重力對(duì)物體做多少功?(與學(xué)生一起算出W1=50J)第2s時(shí)間內(nèi)物體下落的位移是多少?(15m)這1s內(nèi)重力對(duì)物體做多少功?(W2=150J)前1s和后1s重力對(duì)物體做功的功率各是多大?(P1=50W,P2=150W)這2s時(shí)間內(nèi)重力對(duì)物體做功的功率是多大?(P=100W)指出即使是同一個(gè)力對(duì)物體做功,在不同時(shí)間內(nèi)做功的功率也可能是有變化的.因而,用P=W/t求得的功率只能反映t時(shí)間內(nèi)做功的快慢,只具有平均的意義.板書(shū)如下:(1)平均功率: P=W/t(2)瞬時(shí)功率

      為了比較細(xì)致地表示出每時(shí)每刻的做功快慢,引入了瞬時(shí)功率的概念,即瞬時(shí)功率是表示某個(gè)瞬時(shí)做功快慢的物理量.

      提出瞬時(shí)功率如何計(jì)算的問(wèn)題后,作如下推導(dǎo): 一段較短時(shí)間內(nèi)的平均功率可以寫(xiě)成如下公式: P=W/t=W = F·s/ t,而s/t=v 所以:P= F·v 當(dāng)t值足夠小時(shí),v就表示某一時(shí)刻的瞬時(shí)速度,所以這時(shí)P就表示該時(shí)刻的瞬時(shí)功率. 因此 P=F·v 就是瞬時(shí)功率計(jì)算公式 討論:

      ①如果作用于物體上的力F為恒力,且物體以速度v勻速運(yùn)動(dòng),則力對(duì)物體做功的功率保持不變.此

      情況下,任意一段時(shí)間內(nèi)的平均功率與任一瞬時(shí)的瞬時(shí)功率都是相同的. ②很多動(dòng)力機(jī)器通常有一個(gè)額定功率,且通常使其在額定功率狀態(tài)工作(如汽車(chē)),根據(jù)P=Fv可知: 當(dāng)路面阻力較小時(shí),牽引力F也小,v可以大,即汽車(chē)可以跑得快些;

      當(dāng)路面阻力較大,或爬坡時(shí),需要比較大的牽引力,v必須?。@就是爬坡時(shí)汽車(chē)換低速擋的道理. ③如果動(dòng)力機(jī)器原來(lái)在遠(yuǎn)小于額定功率的條件下工作,例如汽車(chē)剛剛起動(dòng)后的一段時(shí)間內(nèi),速度逐漸增大過(guò)程中,牽引力仍可增大,即F和v可以同時(shí)增大,但是這一情況應(yīng)以二者乘積等于額定功率為限度,即當(dāng)Fv=P額.以后,這種情況不可能實(shí)現(xiàn).

      應(yīng)用公式P=Fv計(jì)算m=1kg的物體做自由落體運(yùn)動(dòng)中下落1s末和2s末的瞬時(shí)功率. 由v1=10m/s按公式求得P1=100J;由v2=20m/s按公式求得P2=200J.

      根據(jù)上述結(jié)果啟發(fā)學(xué)生思考瞬時(shí)功率的物理意義.最后指出,此題中是重力對(duì)物體做功,使重力勢(shì)能逐漸向動(dòng)能轉(zhuǎn)化.隨著時(shí)間的延續(xù),重力勢(shì)能向動(dòng)能轉(zhuǎn)化加快.

      3、例題講解

      1、如圖1所示,位于水平面上的物體A的質(zhì)量m=5kg,在F=10N的水平拉力作用下從靜止開(kāi)始向右運(yùn)動(dòng),位移為s=36m時(shí)撤去拉力F.求:在下述兩種條件下,力F對(duì)物體做功的平均功率各是多大?(取g=10m/s2)(1)設(shè)水平面光滑;

      (2)設(shè)物體與水平面間的動(dòng)摩擦因數(shù)μ=0.15. 解答過(guò)程可分為三個(gè)階段:

      ①讓學(xué)生計(jì)算力F在36m位移中所做的功,強(qiáng)調(diào)功只由F和s這兩個(gè)要素決定,與其它因素?zé)o關(guān),因而兩種情況下力F做的功相同,均為W=360J.

      ②由同學(xué)計(jì)算這兩次做功所用的時(shí)間.用牛頓第二定律求出:

      分別求出t1=6s,t2=12s.

      ③用功率的定義式即平均功率的計(jì)算公式求得P1=60W,P2=30W. 如果有的同學(xué)用公式vt2=2αs分別求出每次的末速度,再用公式:

      ,最后用

      求得最后結(jié)果也可以,并指出這是 求出每次的平均速度

      解決問(wèn)題的一另一思路。

      2、如圖2所示,位于水平面上的物體A,在斜向上的恒定拉力作用下,正以v=2m/s的速度向右做勻速直線運(yùn)動(dòng).已知F的大小為100N,方向與速度v的夾角為37°,求:

      (1)拉力F對(duì)物體做功的功率是多大?(2)物體向右運(yùn)動(dòng)10s的過(guò)程中,拉力F對(duì)它做多少功?(sin37°=0.6,cos37°=0.8)通過(guò)此例題的解答,讓學(xué)生掌握功率的計(jì)算公式P=Fvcosα,并提醒學(xué)生,不要認(rèn)為F與v總是在同一直線上;并且知道,在功率已知的條件下,可以用W=P·t計(jì)算一段時(shí)間內(nèi)力所做的功.第(1)問(wèn)的結(jié)果為P=160W;第(2)問(wèn)的結(jié)果為W=1600J. 例

      3、課本p.139上的例題,注意區(qū)分幾個(gè)概念.(三)課堂小結(jié)

      1、我們講了功率概念之后,得到了兩個(gè)公式,定義式P=W/t和瞬時(shí)功率的公式P=F·v.

      2、公式P=W/t中的t趨近于零時(shí),P即為瞬時(shí)功率.不過(guò)此公式主要用來(lái)計(jì)算平均功率.公式P=Fv中,當(dāng)v為瞬時(shí)速度時(shí),P即為瞬時(shí)功率;當(dāng)v用平均速度

      時(shí),也可計(jì)算平均功率.當(dāng)然要注

      所對(duì)應(yīng)的時(shí)間段. 說(shuō)明:

      1、將功率理解為表示能量轉(zhuǎn)化快慢的物理量具有普遍意義.如一臺(tái)電動(dòng)機(jī)的額定功率是10kW,表明它每秒鐘可以將10kJ的電能轉(zhuǎn)化為機(jī)械能,不管它是否工作.因而機(jī)器的功率實(shí)際上可以表示它進(jìn)行能量轉(zhuǎn)化的能力大?。?/p>

      2、力可以做負(fù)功,自然也有負(fù)功率.學(xué)生不問(wèn)到時(shí)可以不講.課本上也沒(méi)講.重要的不是功率的

      正負(fù)問(wèn)題,而是要結(jié)合實(shí)際問(wèn)題說(shuō)清楚能量轉(zhuǎn)化的方向和快慢.例如,一物體沿粗糙水平面向前滑動(dòng),根據(jù)P=f·v可知其機(jī)械能向內(nèi)能轉(zhuǎn)化,轉(zhuǎn)化的快慢與速度v成正比,這就表達(dá)清楚了,沒(méi)有強(qiáng)調(diào)負(fù)功率的必要

      擴(kuò)展資料 額定功率與實(shí)際功率

      額定功率是發(fā)動(dòng)機(jī)正常工作時(shí)的最大功率,通常都在銘牌上標(biāo)明,機(jī)器工作時(shí),必須受額定功率的限制,這是基本原則,發(fā)動(dòng)機(jī)實(shí)際的輸出功率(即實(shí)際功率),可以小于額定功率,在某些情況下,實(shí)際功率也可以略大于額定功率,但不允許長(zhǎng)時(shí)間超過(guò)額定功率.

      關(guān)于汽車(chē)啟動(dòng)的運(yùn)動(dòng)過(guò)程分析

      1、下面我們來(lái)討論汽車(chē)起動(dòng)的模型:(1)以恒定功率起動(dòng),其運(yùn)動(dòng)過(guò)程是:

      2、以恒定加速度起動(dòng),其運(yùn)動(dòng)過(guò)程是:

      機(jī)車(chē)啟動(dòng)的兩種過(guò)程

      、以恒定的功率起動(dòng):

      機(jī)車(chē)以恒定的功率起動(dòng)后,若運(yùn)動(dòng)過(guò)程中所受阻力f不變,由于牽引力,隨v增大,F(xiàn) 減?。鶕?jù)牛頓第二定律,是做加速度減小的加速運(yùn)動(dòng).直至

      ,當(dāng)速度

      v增大時(shí),加速度a減小,其運(yùn)動(dòng)情況

      時(shí),a減小至零,此后速度不再增大,速度達(dá)到最大值而做

      勻速運(yùn)動(dòng),做勻速直線運(yùn)動(dòng)的速度是,下面是這個(gè)動(dòng)態(tài)過(guò)程的簡(jiǎn)單方框圖

      這一過(guò)程的v-t關(guān)系如圖所示.

      2、車(chē)以恒定的加速度a起動(dòng). 由 知,當(dāng)加速度a不變時(shí),發(fā)動(dòng)機(jī)牽引力F恒定,再由 知,F(xiàn)一定,發(fā)動(dòng)機(jī)實(shí)際輸出功率P隨v的增大而增大,但當(dāng)P增大到額定功率以后不再增大,此后,發(fā)動(dòng)機(jī)保持額定

      功率不變,v繼續(xù)增大,牽引力

      P增至

      時(shí),F(xiàn)減小,直至 后勻速運(yùn)動(dòng).,車(chē)速達(dá)到最大值

      ,此

      之前,車(chē)勻加速運(yùn)動(dòng),其持續(xù)時(shí)間為

      (這個(gè)

      必定小于

      ,它是車(chē)的功率增至

      之時(shí)的瞬時(shí)速度).計(jì)算時(shí),先算出F ;

      ,再求出

      在P增至 圖,最后根據(jù) 求

      t.

      .下面是這個(gè)動(dòng)態(tài)過(guò)程的簡(jiǎn)單方框

      之后,為加速度減小的加速運(yùn)動(dòng).直至達(dá)到

      這一過(guò)程的v-t關(guān)系如圖所示。

      習(xí)題精選

      (一)1.質(zhì)量為m的物體自高處自由落下,時(shí)間t內(nèi)重力的平均功率為_(kāi)____,t秒末重力的瞬時(shí)功率為_(kāi)____.2.設(shè)飛機(jī)飛行時(shí)所受的阻力與其速度的平方成正比.如果飛機(jī)以速度v勻速飛行時(shí)其發(fā)動(dòng)機(jī)的功率為P,則飛機(jī)以2v的速度勻速飛行時(shí)其發(fā)動(dòng)機(jī)的功率為_(kāi)____.3.起重機(jī)的鋼繩吊著物體由靜止開(kāi)始豎直向上運(yùn)動(dòng),先以加速度a(a<g)加速運(yùn)動(dòng)再勻速運(yùn)動(dòng),最后減速運(yùn)動(dòng)到靜止,則關(guān)于各段運(yùn)動(dòng)中繩的拉力的平均功率,下列說(shuō)法中正確的是 A.第一段平均功率最大 B.第二段平均功率最大

      薦初二物理《浮力》教學(xué)案例(5000薦薦初初二中物物理

      教理

      案教

      學(xué)

      案物

      態(tài)例

      字)

      薦初中物理教學(xué)設(shè)計(jì)和反思(3000字)薦初中物理教學(xué)案例《密度》(800字)

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