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Intro to springs and Hooke's law | Work and energy | Physics | Khan Academy

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  • čas přidán 14. 04. 2008
  • Courses on Khan Academy are always 100% free. Start practicing-and saving your progress-now: www.khanacadem...
    Introduction to Hooke's Law. Created by Sal Khan.
    Watch the next lesson: www.khanacadem...
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    Physics on Khan Academy: Physics is the study of the basic principles that govern the physical world around us. We'll start by looking at motion itself. Then, we'll learn about forces, momentum, energy, and other concepts in lots of different physical situations. To get the most out of physics, you'll need a solid understanding of algebra and a basic understanding of trigonometry.
    About Khan Academy: Khan Academy offers practice exercises, instructional videos, and a personalized learning dashboard that empower learners to study at their own pace in and outside of the classroom. We tackle math, science, computer programming, history, art history, economics, and more. Our math missions guide learners from kindergarten to calculus using state-of-the-art, adaptive technology that identifies strengths and learning gaps. We've also partnered with institutions like NASA, The Museum of Modern Art, The California Academy of Sciences, and MIT to offer specialized content.
    For free. For everyone. Forever. #YouCanLearnAnything
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Komentáře • 234

  • @JohnHorak
    @JohnHorak Před 11 lety +83

    I think the people who go out of their way to put videos up on youtube for free generally have an enthusiasm that not all teachers have (some anyway)

    • @ryanechelberger7035
      @ryanechelberger7035 Před 10 měsíci

      He makes money off the video though

    • @butimohammed3264
      @butimohammed3264 Před 7 měsíci

      @@ryanechelberger7035 it is still generous of him, how much he could be making from online paid courses isnt even close to what he makes from youtube.

    • @Peter_1986
      @Peter_1986 Před 7 měsíci +1

      @@ryanechelberger7035 Yes, but his channel was created because he started out with helping people for free, and he insists that people should be able to use it for free without being forced to pay for it.

    • @virajyadav3826
      @virajyadav3826 Před 5 měsíci

      its a fundraiser
      @@ryanechelberger7035

  • @ZnNlove
    @ZnNlove Před 8 lety +207

    Good ol' days of 240p Khan Academy

  • @Peter_1986
    @Peter_1986 Před 11 lety +79

    I believe the typical flaw of many physics teachers is that they don't really explain things in-depth, they just shove formulas into your face and tell you to calculate something.
    Anyone can put numbers into formulas, the real challenge in physics is to actually understand what's going on and WHY the formulas look the way they do.
    Khan is very good at explaining those kinds of things, and it gives you a much better intuition.

  • @asparwhite86
    @asparwhite86 Před 8 lety +45

    You totally kick my professor's ass.

    • @jeff30458
      @jeff30458 Před 7 lety +3

      mine too, my online class is a joke.

  • @iieeKatey
    @iieeKatey Před 11 lety +12

    Why wasn't the restorative force in the last example -2N instead of 2N since it was acting to the left?

  • @Icareaboutyourapple
    @Icareaboutyourapple Před 4 lety +6

    wow when he says that he has run out of time bc the video was posted in 2008 and YT videos could only be uploaded at 10 minutes max. Oh how the days have changed.

  • @cg2203
    @cg2203 Před 10 lety +54

    click the little settings cog and above quality change the speed to 1.5. exams are too soooon

    • @notveryrea1
      @notveryrea1 Před 5 lety +5

      Saaaameee literally tmr

    • @brawlboi2946
      @brawlboi2946 Před 4 lety +4

      Lol, I have my SAT Subject Tests tomorrow (2nd November)

    • @brawlboi2946
      @brawlboi2946 Před 3 lety

      @Jesus bruh, it's been so long

  • @mannyStern
    @mannyStern Před 14 lety +11

    Sal, I am a retired former physicist trying to relearn what I used to know. Can you please tell me what grade level physics you are targeting?
    Since I have not looked or thought of physics for 40 years, I am having a ball with your videos.

  • @lucasbassuk3796
    @lucasbassuk3796 Před rokem +7

    This video is older than me, yet here I am using it

  • @AT-ki3px
    @AT-ki3px Před 11 lety +7

    When I am in class, I'm like, "GOD WHAT CAN'T THIS PHYSICS CLASS BE SHORTER..." When I am watching this video, I'm like, "GOD WHY CANT THIS VIDEO BE LONGER..." ;)

  • @Mitchelloni95
    @Mitchelloni95 Před 11 lety +9

    Thank you so much! I was feeling a little shaky about a few things for my Physics exam that I forgot to ask my teacher, and these videos have really cleared things up!

  • @edgroves3672
    @edgroves3672 Před 9 lety +46

    skip forward a few seconds if it isnt loading

  • @AnastasiaDinda
    @AnastasiaDinda Před 8 lety +26

    Watching your videos always makes me envy the kind of education developed countries get, where i'm from physics might as well be math with different units ..

    • @yesyes4005
      @yesyes4005 Před 8 lety +2

      keep blaming your environment. Fucking loser .

    • @iMusikkForeva
      @iMusikkForeva Před 8 lety +22

      +YES! Yes! How rude and arrogant! She's voicing her opinion, there's no need to judge her. Moreover, you know nothing about where's she's from or the struggles she has, so don't try and act like it's nothing. We all have problems in life, and yes...the environemnt does matter. Some students simply don't have the same opportunities and facilities as others, and this is an universal fact. Furthermore, an overwhelming percent of the time it DOES create an impact on the future of the students. So focus on your own life, and keep your negative attitude outside of others'.

    • @BLURtm
      @BLURtm Před 8 lety +2

      I completely agree with you iMusikkForeva.

    • @yesyes4005
      @yesyes4005 Před 8 lety

      You have a notification

  • @truthwelltold5
    @truthwelltold5 Před 6 lety +210

    Who doesn't understand physics like me?

  • @captainspiwtf
    @captainspiwtf Před 15 lety +28

    Hey Sal, I remember hearing you say you can code too.
    You are a brilliant teacher, could you do some video tutorials on C++ or some other programming language? Its a lot to ask but it'd be amazing... thanks anyway man.

  • @ViizVenomZz
    @ViizVenomZz Před 9 lety +13

    go to settings put the graphics to 240p and it will surely work :}

  • @MattSiegel
    @MattSiegel Před 10 lety +40

    20 metres? that is a lonnnnng spring

  • @ull893
    @ull893 Před 13 lety +5

    All your videos there is one thing common...at some point in the explanation you hit the bulls eye of explaining the logic behind the topic..that makes it interesting rather than blindly bye hearting the formulas...Thank you very much..

  • @muhammadhaziqhafizuddin5411

    In the last example, why the sign of restoring force is positive?

  • @hanashah1
    @hanashah1 Před 7 lety +8

    Thanks for the great expanation! May the FORCE be with you :)

  • @C3Daddy0
    @C3Daddy0 Před 10 lety +29

    KHAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAN!!!!!!!!

  • @yasiru221
    @yasiru221 Před 9 lety +25

    video doesnt load for me, tried it on both youtube and khanacademy site, doesnt work

    • @nathanc9110
      @nathanc9110 Před 9 lety +15

      try it in 240p, i was having the same problem, but 240p worked for me.

    • @quantum_fluff1344
      @quantum_fluff1344 Před 9 lety +2

      Nathan Cameron thx mate really needed that :)

  • @abhishekbhattacharjee4639

    you have come a long way sal

  • @MulleDK19
    @MulleDK19 Před 15 lety +5

    "If you stretch something too much, it never really goes back to where it was before"... I lol'ed xD
    Awesome videos, btw. Keep going!

  • @sakirhossain
    @sakirhossain Před 12 lety +3

    When u pulled the spring 2N to the right the Resistance force is -2N. and since you move 1 meter,
    F= - K X
    -2N= -k * 1m
    k= 2 not -2

  • @pinksugarlylove
    @pinksugarlylove Před 15 lety +7

    Thank you so much(: Love the video, it really helped me alot A LOT(: May God Bless YOU(:

  • @g3mint446
    @g3mint446 Před 9 lety +41

    Video won't load...

  • @doreenstanley1507
    @doreenstanley1507 Před 10 lety +50

    Restorative force for the last example is NEGATIVE 2; I think Khan put positive 2 by mistake

    • @yourpapidario
      @yourpapidario Před 9 lety +6

      youre right

    • @KingBarney
      @KingBarney Před 9 lety +6

      Yeah, noticed that, too.
      I love when I understand well enough in the beginning to recognize a mistake later on in the video. Makes me feel a bit confused but also let's me know I understand well enough to even recognize mistakes.

    • @simontalamantes3610
      @simontalamantes3610 Před 9 lety +2

      Lol king Barney? Not on skate or mortal combat videos? Get outta here

    • @KingBarney
      @KingBarney Před 9 lety

      Simon Talamantes Hahaha. Got a final exam in 4 hours. xD

    • @simontalamantes3610
      @simontalamantes3610 Před 9 lety

      How'd ya do Barney?

  • @Celicaw8
    @Celicaw8 Před 8 lety +3

    -5N to the left direction (as drawn) means 5N to the right

  • @robertchristian4248
    @robertchristian4248 Před 4 lety +2

    11 years later and we are all still here

    • @layakrishnan5999
      @layakrishnan5999 Před 4 lety

      I know right

    • @mastersanada
      @mastersanada Před 4 lety

      Cause Physics can't explain jackshit. (Well, in my case my teacher teaches so slow and so incoherently that everyone falls asleep and no one learns anything except those people who already know all of AP Physics)

  • @m1h2al3
    @m1h2al3 Před 8 lety +75

    he's really good at explaining, but he spends tooooo much time drawing and wasting time over silly things

    • @dr.najeebullahqadir5858
      @dr.najeebullahqadir5858 Před 6 lety +3

      play the video at 1.25 or 1.5 times the original speed

    • @chainsamguacamole6647
      @chainsamguacamole6647 Před 5 lety +2

      Since this is an earlier video, maybe he wasn't as used to the software as he is now. Now he doesn't waste as much time with these things. At least this is what I think.

    • @diegoguatemala1520
      @diegoguatemala1520 Před 5 lety +3

      clearly you were not paying attention my friend hahahahahaha who cares when you need to learn?

    • @charmendro
      @charmendro Před 5 lety +9

      I think it’s good for people who need more time to process.

  • @stevensosa5995
    @stevensosa5995 Před 6 lety +1

    Thank you!

  • @t-h787
    @t-h787 Před 6 lety +18

    the quality of the video looks like it was recorded using a calculator

  • @BenLewisE
    @BenLewisE Před 11 lety +2

    I can tell you as a student that often students don't want to be in lessons or don't care about what their teacher is saying, but if a student stays around long enough to watch a video then they definitely care enough about the topic or like way it's taught and it's a convenient time for them. Hence students always find educational videos more convenient and hence better.

  • @equaygaming229
    @equaygaming229 Před 7 lety +3

    Hooke's law states that the extension of a spring is directly proportionate to the force applied.

  • @xenomann442
    @xenomann442 Před 10 lety +1

    Because lots of teachers don't fully understand what they are teaching. They know how to get the right answer, in terms of using the formulas correctly, but I bet you they couldn't break down what that formula is actually doing... They don't understand WHY the formula works essentially. Don't get me wrong there a lots of awesome teachers (from my experience at least), but there are also too many that simply teach the curriculum, without an in-depth understanding of what they teach.

  • @sidneyreed1031
    @sidneyreed1031 Před 7 lety +4

    Surely the signs for the last question would have to change??

  • @Julie59105
    @Julie59105 Před 11 lety

    These people actually know how to teach, verses others that attempt to teach.

  • @uniqua2621
    @uniqua2621 Před 2 lety +1

    I was only 3 when this was released and now Its finally my turn.

  • @LaserMonkey
    @LaserMonkey Před 3 lety +2

    10 meters?! Now thats one big spring!

  • @Deaddev1l99
    @Deaddev1l99 Před 11 lety +1

    You're right. K should be 2 in the last equation.

  • @XxAlessiaxX1
    @XxAlessiaxX1 Před 8 lety +1

    i can always rely on you

  • @charmendro
    @charmendro Před 5 lety +1

    Wouldn’t F=2x in the last example ? Since u had k = -2 therefore -(-2)x would be the function

  • @dbrothers6329
    @dbrothers6329 Před 3 měsíci +1

    its crazy that this video is older than I am

  • @QuicklimeProductions
    @QuicklimeProductions Před 11 lety

    newton must feel like such a badass, forget a building or even a species or a star, he has a force of nature named after him.

  • @kylebtw3625
    @kylebtw3625 Před rokem

    Thank you

  • @Breaker5764
    @Breaker5764 Před 13 lety +1

    @NPowah But spring force should be in the opposite direction...I thiink Sal is wrong, because the APPLIED force he used was (+2 N) and the restorative force (spring force) he put down was (+2 N). He's solving for K, so conceptually, he should put down the correct F to get the correct K. If he was solving for F, then yea, the (-) would factor itself in to get the spring force (F) in the opposite direction and all you would need to worry about is getting the correct sign for distance.

  • @hey-go4dg
    @hey-go4dg Před 7 lety

    helped me alot thanku so much

  • @surroundsound5000
    @surroundsound5000 Před 15 lety

    "Hooke's law states that the force produced by a compressed spring is dependent on the amount by which the spring is compressed. If a spring compressed by 1 cm requires a force of 1 newton, then compressing the same spring by 2cm will require 2 newtons of force."

  • @namratachauhan6386
    @namratachauhan6386 Před 10 lety

    thanks Mr. Khan.

  • @maquistom5837
    @maquistom5837 Před 10 lety

    You would have to watch Khan for a month or so without a break in order to watch all their videos. I just calculated it assuming the videos average 10 min in length. Better start somewhere...;)

  • @NPowah
    @NPowah Před 14 lety

    @ mygremg
    Sal is actually correct, since he is discussing the Force of the spring, which is F = -kx

  • @hazemalsoweed3729
    @hazemalsoweed3729 Před 7 lety

    Thanks khan academy

  • @spoonfullofsalt8889
    @spoonfullofsalt8889 Před rokem

    I fell asleep in my physics class explaining springs and Hookes Law, this video is a total lifesaver

  • @SupremeCoalition
    @SupremeCoalition Před 15 lety

    thank you! very useful.

  • @megashani91
    @megashani91 Před 11 lety +1

    I bet he has a higher pass rate than your "professional and organized" teacher who prepares for classes

  • @equaygaming229
    @equaygaming229 Před 7 lety

    Getting this on my test ;)

  • @BengBengCat
    @BengBengCat Před 14 lety

    Thanks so much

  • @farzanamariyam4665
    @farzanamariyam4665 Před 5 lety

    If I take positive X to right and negative to left since force is also a vector quantity shouldn't it b negative to left as well?

  • @pandemade3875
    @pandemade3875 Před 8 lety +7

    isnt it supposed to be f=-(-2)x for the 2nd question? anyone?

    • @iMusikkForeva
      @iMusikkForeva Před 8 lety +3

      Yes, that's exactly what I was thinking!

    • @supergolfer8337
      @supergolfer8337 Před 8 lety +2

      yes

    • @hagerebraheem1295
      @hagerebraheem1295 Před 7 lety

      he assumed that (k) is positive for all purposes and if k is negative number besides the negative sign and x for example in the positive direction the conservation force would be in the same direction and the same if x in the negative direction which is wrong

  • @benjaminneufeld6137
    @benjaminneufeld6137 Před 10 lety +1

    how does the 1/2 part come into play in the restoring force =-kx formula

  • @khiemluong4591
    @khiemluong4591 Před 7 lety +3

    so F is not the applied force?

  • @bhuvi441
    @bhuvi441 Před 7 lety

    So even if I move a car by distance x or if I move a pin by the same distance X then the force applied by me is the same for both cases ??

  • @fwesterbergh
    @fwesterbergh Před 10 lety +3

    But if the spring is at rest the restoring force must be zero?

    • @MattSiegel
      @MattSiegel Před 10 lety +3

      The spring is only at rest because you're still pushing on it. If you stopped pushing it would spring back at you. *That's* the restorative force :)

  • @volintine
    @volintine Před 15 lety

    thnx sal

  • @bagyaaluthge3111
    @bagyaaluthge3111 Před 5 lety

    Ty

  • @Bennethp
    @Bennethp Před 6 lety +1

    I wish they would redevelop these videos

  • @pithikoulis
    @pithikoulis Před 14 lety

    thanks loads :D

  • @slickwillie3376
    @slickwillie3376 Před 10 měsíci

    So, to make a three inch long shock absorber (.076 meters) for a cane, that will support a body weight of 220 pounds (979 N), then
    F = 979 N = .076 × k
    k = 979N / .076 = 12,882
    If I am willing to double the length of the shock absorber, then k = 6,441, which might be cheaper.

  • @edsradio5817
    @edsradio5817 Před 4 lety

    This man is god

  • @Stickbabiga
    @Stickbabiga Před 13 lety +1

    Why do ALL educational videos teach people more in 10 minutes than their teachers do in 10 days?

  • @user-ez1sz8yb7f
    @user-ez1sz8yb7f Před 3 lety

    What does Hooke's law depend on?

  • @badguyfromstarwars
    @badguyfromstarwars Před 11 lety

    Shouldn't the value of K in the last example be positive due to the fact that the force isn't put to compress? In that way it's negative from the beginning, -2N to counteract the positive force of 2N?

  • @alexiskruljac9201
    @alexiskruljac9201 Před 4 lety

    At the end of the video, why isnt the restorative force -2 since its acting in the opposite direction?

  • @KashmalaNawab
    @KashmalaNawab Před měsícem

    Oh my god when this video was uploaded I was just 1 month old

  • @megashani91
    @megashani91 Před 11 lety

    yes i think he created another video to correct this

  • @paypuhboy2863
    @paypuhboy2863 Před 9 lety

    love you KHAN

  • @hey-go4dg
    @hey-go4dg Před 7 lety +1

    in the last question isn't restorative force -2 Newton cause it's acting towards the left?

  • @momentlikethat
    @momentlikethat Před 12 lety

    yeah I figured that out later

  • @NomanKhan-lo4tc
    @NomanKhan-lo4tc Před 4 lety

    Good

  • @RadialEffects
    @RadialEffects Před 12 lety

    the force is strong in this one

  • @MattyHild
    @MattyHild Před 13 lety

    Would gravity have the same effect on a spring that is attached to a roof/ceiling?

  • @dravidr007
    @dravidr007 Před 13 lety

    can u go into finite element analysis

  • @cjitfc6731
    @cjitfc6731 Před 4 lety +3

    I understood none of this

  • @SpankAgoose
    @SpankAgoose Před 13 lety

    Can you make video about elasticity please?

  • @davidkim0678
    @davidkim0678 Před 11 lety +1

    well his subscribers and like ratios tell otherwise....therefore your comment is invalid.

  • @seonghwa8902
    @seonghwa8902 Před 4 lety

    may i asked why the formula is F= -kx ? because in my textbook and reference books it said F = kx

  • @bananian
    @bananian Před 12 lety +2

    Is there a Springe's law for hook physics?

    • @andrewm2786
      @andrewm2786 Před 2 lety +2

      this joke went unappreciated for 9 years...but I'm here for you. I laughed.

    • @bananian
      @bananian Před 2 lety +2

      @@andrewm2786
      I've been waiting for this moment for 9 years :_)

    • @haroonk.9706
      @haroonk.9706 Před rokem +2

      @@bananian you must be long done school at this point

    • @RanveerSingh-sv9co
      @RanveerSingh-sv9co Před rokem

      @@haroonk.9706 yea, let's see

  • @MyVitros
    @MyVitros Před 3 lety

    To the left to the left

  • @VannAleXX
    @VannAleXX Před 11 lety

    Wouldn't k in the second equation be 2 and not -2? Since he's applying the force in the positive direction, the restorative force would be negative, so -2=k*1, so k=-2? Isn't that what he did in the first example?

  • @wasihhassan403
    @wasihhassan403 Před 3 lety +1

    can someone please explain what k is in hookes law?

  • @MadinaAfg94
    @MadinaAfg94 Před 12 lety

    00.26. That's what he said

  • @slownightsolongg
    @slownightsolongg Před 13 lety

    @LOLzxcvb the spring constant, its different for different types of springs and shows how stiff a spring is.

  • @coltonsssss
    @coltonsssss Před 8 lety +1

    thats a big spring

  • @y.alenezi5747
    @y.alenezi5747 Před 2 lety +1

    Useful video but not the one looking for. Like

  • @anishbachan4763
    @anishbachan4763 Před 11 lety

    ikr

  • @essamcream6194
    @essamcream6194 Před 9 lety

    Its fine now

  • @jerrycornelius6335
    @jerrycornelius6335 Před 4 lety

    OK--What is the name for a spring that is used in click clack device and also a clutch plate spring as the same. You apply force and when you reach over halfway the spring then continues. On a new Clutch you will feel the resistance and the it pulls itself in.??? come on ? I cannot remember the name??

  • @Meckro
    @Meckro Před 8 lety +1

    240p This is HD CZcams quality right here!

    • @925LY
      @925LY Před 7 lety +1

      made in 2008

  • @anishbachan4763
    @anishbachan4763 Před 11 lety

    ya