Archimedes principle and buoyant force | Fluids | Physics | Khan Academy

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  • Опубликовано: 13 янв 2025

Комментарии • 120

  • @arnoldchristian9501
    @arnoldchristian9501 7 лет назад +128

    Bro how do you know every single thing in the world? lmao

  • @artakisthebest
    @artakisthebest 12 лет назад +26

    hehe, I actually only made it halfway through his trigonometry playlist the day before my trig exam havving never looked at my other teachers notes, and got 84 percent in my trig exam! And that was a college level test :D

  • @joeymama648
    @joeymama648 11 лет назад +11

    his voice is SOOOOO relaxing

  • @MaxGunter97
    @MaxGunter97 6 лет назад +76

    "If you can't explain it simply, you don't understand it well enough." -Albert Einstein

    • @the_unconscious_mindthe_le3344
      @the_unconscious_mindthe_le3344 6 лет назад +2

      Maxwell Gunter 😂😂😂😆😃

    • @Ndfull
      @Ndfull 2 года назад

      @@the_unconscious_mindthe_le3344 1qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqquq

    • @Ndfull
      @Ndfull 2 года назад

      @@the_unconscious_mindthe_le3344 0000000

  • @kanaeroseweld2237
    @kanaeroseweld2237 Год назад +1

    Thanks bro. I have been trying to undertsand this principle for hours. You saved me days of trying to think. Thanks

  • @sehmio
    @sehmio 7 лет назад +13

    This was fantastic! Background in why its F=pvg!

  • @dst7ssa
    @dst7ssa 15 лет назад +4

    Funny I have a fluids exam tomorrow and am gaining confidence as I watch your videos. I cant believe I didn't see this before my first exams. Now I feel like I understand enough to actually teach someone. Captain Sal explain things so simply like you do . thanks

    • @Smokie_bear9896
      @Smokie_bear9896 6 лет назад +1

      woah you’re from the past

    • @ottavari746
      @ottavari746 6 лет назад

      Smokie Bear lol

    • @Aalijah_Matyevna
      @Aalijah_Matyevna 2 года назад +1

      Were you in college at that time?You have grown up so much now then.

    • @amirabbas0
      @amirabbas0 Год назад

      @@Smokie_bear9896 now you're from the past

    • @Smokie_bear9896
      @Smokie_bear9896 Год назад

      @@amirabbas0 now i'm from the present

  • @TACZero1
    @TACZero1 12 лет назад +2

    My teacher for some reason made us learn fluids by ourselves, which i think is the hardest thing we've done so far. so thank you for your videos because i have been so lost

  • @niconikko
    @niconikko 13 лет назад +3

    Mr. Sal, you're not just a great teacher, but you're also a great magician. You helped us in showing the formula for buoyant force like magic. THANKS!!!

  • @sureshchandrapal2320
    @sureshchandrapal2320 3 года назад +1

    Thank u so much....I was extremely confused in it but now it is crystal clear ....thank u million times
    Hare krishna

  • @NilanjanaLodh
    @NilanjanaLodh 14 лет назад +1

    really wonderful!!no other video on the net is as good as urs!u jus rock

  • @nenoo1536
    @nenoo1536 2 года назад +2

    this is actually really helpful!! bless you :)

  • @artakisthebest
    @artakisthebest 12 лет назад +7

    respect man, figuring things out for yourself will really make sure it sticks in your brain! I aspire to be an engineer, and I could never just 'trust' in all the formulas I use, Id like to prove them myself. I hope I can say the same when im in the last year of my degree where things are bound to be not as intuitive. At the moment im having trouble grapsing the concept of Enthalpy. Do you think you could explain enthalpy for me :P

    • @soumyashreebiswal14
      @soumyashreebiswal14 2 года назад +1

      Absolutely agree with you, man! Same aim here, and I too always try to prove stuff myself. Not a bad habit to have, is it? (Jeez when you commented this, I was like 8 years old haha)

  • @htavli
    @htavli 3 года назад +1

    This video was very helpful. Thank you!

  • @ArchmageMokokong
    @ArchmageMokokong 6 лет назад

    his voice is sooo relaxing and his video is so wonderful teacher to me.

  • @nu.wa.n
    @nu.wa.n 8 лет назад +10

    the explanation that finally ties it all to weight is really really neat.

  • @megaelliott
    @megaelliott 15 лет назад +2

    Look up rho(greek alphabet) on google and you will see that the capital version looks slightly different. I advise that you use that as rho in your own work as it is less confusing

  • @ParadiXe311
    @ParadiXe311 3 года назад +2

    This video was so educational, I just jumped out of the bathtub, running down the street naked, yelling "Eureka!"

  • @MandaNovokmet
    @MandaNovokmet 7 лет назад +1

    This is a beautiful video!! Really made the concept clear, thank you! God bless

  • @MellowCruisin
    @MellowCruisin 14 лет назад +1

    I have a question for you. If an object is at the very bottom of a jar of water with no room for water between the object and bottom of jar, how does the object still buoy up if there isn't water below it?

  • @Chelsea-gs7qj
    @Chelsea-gs7qj 8 лет назад +53

    I usually love these videos but I'm literally lost

    • @keamorshedsoccer1382
      @keamorshedsoccer1382 7 лет назад +3

      Chelsea Osuji Khan made this video wayyyyyy to mathematic🙏🏽😬

  • @sergiomuniz350
    @sergiomuniz350 6 лет назад

    great video. in the book they have f= gamma times the volume in which you have d cubed times rho times gravity and rho times gravity makes gamma so that explains a lot.

  • @bubbybumble616
    @bubbybumble616 3 года назад +1

    bro how does this video from 2008 perfectly explain one of the harder concepts for me to grasp. how did I not understand this before?

  • @anber4129
    @anber4129 5 лет назад

    Beautifully done. Very easy to follow. Very flowing.

  • @SwayamKrishnaartsandcrafts
    @SwayamKrishnaartsandcrafts Год назад

    It has been 15 yrs but still this video helps

  • @abdosamr4639
    @abdosamr4639 3 года назад +1

    Pressure acts in perpendicular directions, not in all directions.

  • @MitchelChabu-yl2xp
    @MitchelChabu-yl2xp Год назад

    You make me want to say I love physics

  • @firaolmulugeta9928
    @firaolmulugeta9928 4 года назад +1

    wow very nice i uderstand every thing what he says

  • @josemolina5423
    @josemolina5423 7 лет назад +7

    Water molecule as a sphere?
    J. Dalton likes this

  • @artakisthebest
    @artakisthebest 12 лет назад

    Wow that was a very intuitive example my friend! Did you read that somewhere or you thought of it, I think thats beautiful, really complements the mathematical proof of archimedes principle well.

  • @psbbiaku640
    @psbbiaku640 7 лет назад +1

    hey sal I am ur no.1 fan

  • @flimsyfox
    @flimsyfox 4 года назад

    I just had a "mind-blown" moment.

  • @kanikachaudhary6089
    @kanikachaudhary6089 4 года назад +1

    ONE QUESTION HOW PRESSURE ACTING IN ALL DIRECTION IT SHOULD ACT DOWNWARD ONLY HOW LEFT AND RIGHT

  • @BettyNalugo-et9sp
    @BettyNalugo-et9sp Год назад

    so wonderful 💖

  • @stephenkong3155
    @stephenkong3155 7 лет назад +1

    May I ask why does the net force equals to the buoyant force? Like what's the reason they equal?

  • @hemantvaish5658
    @hemantvaish5658 7 лет назад

    good vidd
    sir plz aaap practically videos banayq karo
    jaise aaap specific gravity ki bnayai hh
    vry nyc vidd
    plzz

  • @willpaisley7828
    @willpaisley7828 7 лет назад +3

    Does this assume the mass of the cube is negligible

  • @SAISRIKAR2002
    @SAISRIKAR2002 6 лет назад +3

    What happened to the wEight of the cube while calculating the net force?

    • @Jay-jk7jv
      @Jay-jk7jv 3 года назад

      The net force calculated here is the force acting on the cube due to pressure. The weight of the cube is acting downwards while the net force due to pressure is acting upwards. That means the net force due to pressure will work against the weight of the cube. This is what makes the cube feel lighter when it’s in the liquid.
      I'm 2 years late, but I just learned this concept from this video and thought I should answer. You know, just to see if I can explain it:)

  • @reesejpuc
    @reesejpuc 14 лет назад +1

    sal, 100 years from now, you will have your own unit of measurement named after you. The sal or the kahn.

  • @vinayseth1114
    @vinayseth1114 8 лет назад +3

    But shouldn't the net force be 0, otherwise the cube would keep jutting upwards and then get pushed out of the water?

    • @amrshehab7019
      @amrshehab7019 6 лет назад +2

      It is another thing he is just calculating the net force due to the pressure difference which is called buyonce force but there is also another force which is the gravity so when we apply neowton’s second law on this body we will say that the net force = mg (gravity[downwards]) - B (buyonce force[upwards])
      And if they are equal it will be submerged in the fluid if the gravity is greater it will sink if buyonce force is greater it will float untill some of it get out of the fluid that the dicplaced fluid is less so the buyonce force is less to be in equilibrium with the force of gravity

  • @slmUSA
    @slmUSA 14 лет назад +1

    Thank you!

  • @nolwazihlophe580
    @nolwazihlophe580 5 лет назад +1

    thank you

  • @specialparadise
    @specialparadise 7 лет назад +7

    Anyone else had a Eureka moment?

  • @rotflmaopmpqxyz
    @rotflmaopmpqxyz 14 лет назад +1

    So P stands for pressure, and p is also units for momentum AND density? these confuse me. Also Mass and meters confuse me too

  • @dravinashiyer936
    @dravinashiyer936 6 лет назад

    With the hydrostatic eqn derive bouyant force of submerged body.. Put answer of this question please

  • @ANUPAMAMATHEWPHD
    @ANUPAMAMATHEWPHD 6 лет назад

    Is the box in static equilibrium or is it moving up??

  • @KavangWase
    @KavangWase Год назад

    I'm confuse. Fnet=(d•p•g)d^2 if you are going to expand that, why does both density (p) and gravitational acceleration (g) are not multipled by d^2 and only d is multipled by d^2 giving d^3?

  • @SkyOnUrSide
    @SkyOnUrSide 2 года назад +2

    ITS FREAKING 2022 it was 2008 dayum

  • @gretawilliams8799
    @gretawilliams8799 7 лет назад

    That's through physics perspective but...
    The answer of why upthrust is created, is purely philosophical...
    Does pure water produce upthrust?? I think, upthrust effect is due to the repulsion between same charged ions....
    How do you put it(philosophy) into science ...
    The tendency of any body to remain undisturbed or in their natural state, upthrust is due to them resisting disturbance,.
    That's basically all upward directed forces: Normal contact force, Upthrust, ....

  • @drdkvetbiotech
    @drdkvetbiotech 8 лет назад +4

    why didn't we multiply d^2 with g and rho?

    • @rjk368
      @rjk368 7 лет назад +3

      I believe it was (dpg)*d^2. However, (dpg) means (d*p*g), not (d+p+g). So, it is (d*p*g)*d^2. Now, multiplication is commutative (can be done in any order) and associative (grouping doesn't matter if all operations are multiplication). Since all of the operations are multiplication, it is: d* p * g * d^2 = d * d^2 * p * g = d^3 * p * g. The reason you don't distribute is because you only distribute the coefficient when the operation inside the parentheses is addition (for example, 2(4+6) = 2 * 4 + 2 * 6 = 8 + 12 = 20).

    • @91755103
      @91755103 7 лет назад

      It's just to show that the buoyant force is the product of the volume displaced by the submerged object, and the liquid's specific weight.

  • @himanshusharma9981
    @himanshusharma9981 6 лет назад

    nice derivation, but what if we take the example of a human being and try to derive Archimedes principle .how will u take out the volume of a human.

  • @fablihakhan9265
    @fablihakhan9265 7 лет назад +2

    Why am i not taking the height from the very bottom of the cup to determine the pressure at the bottom of the cube?

    • @fablihakhan9265
      @fablihakhan9265 7 лет назад

      Since the water from below the cube is also exerting some pressure on the cube

    • @36sufchan
      @36sufchan 7 лет назад

      If you consider height from the bottom; then it would make pressure higher at more distant points from the Earth (slightly less acceleration due to gravity); but since it doesn't work for columns infinitely long, it is not acceptable.

  • @fufuisgood
    @fufuisgood 6 лет назад

    I did not quite understand "volume of the water displaced" I'm from Denmark and your videos are very helpful, but there's one thing that I did not quite catch..

    • @Arafat-my6fe
      @Arafat-my6fe 4 года назад +1

      when u stick an object into the water, and exactly where u stick it into the water, the water of that very place has to move out to make room for the object u r sticking or putting there. And the volume or amount of water was moved(displaced) is called the volume of the water displaced. Hope, that helps. 😀

    • @fufuisgood
      @fufuisgood 4 года назад +1

      @@Arafat-my6fe thankyou!! I totally forgot about it since it was 2 years ago ahahah

  • @mousaalsaeed9410
    @mousaalsaeed9410 7 лет назад +1

    what happened for weight of object ??

  • @maxtan4471
    @maxtan4471 3 года назад

    Why the force act on the top and bottom of the cube are not the same, since it is in static form?

  • @taymrafid9139
    @taymrafid9139 3 года назад +1

    My guy made the video before I was born lmao

  • @CcanCcaglar
    @CcanCcaglar 14 лет назад +3

    omg khan when im rich im guna give you so much money

  • @anotherdoseyt
    @anotherdoseyt 7 лет назад

    So straight to a cup of water... no good morning 😂

  • @amrshehab7019
    @amrshehab7019 6 лет назад

    But this prove is for regular body how could we apply archemedis principle for spheres and irregular bodies ?

  • @illiums410
    @illiums410 8 лет назад +6

    Hotel?

  • @adas2922
    @adas2922 11 лет назад

    thanks

  • @spatel6230
    @spatel6230 4 года назад +1

    when Sal cancelled out those two phg's, I may have been more aroused than I've ever been in my life

  • @Ichneumonidae2
    @Ichneumonidae2 12 лет назад

    great video, thanks!

  • @LNasterio
    @LNasterio 12 лет назад

    Imagine a cup of water as a box of solid balls.
    when you sink into middle of that box of solid balls.
    the balls on top will apply a force acting you downwards right?
    and the balls at the bottom of you will apply a "reaction force" acting on you upwards, And this reaction force is equal to weight of the object within the water plus the "balls"
    on top
    hope it make sense?

  • @DbzFighter02
    @DbzFighter02 12 лет назад +1

    2 years later, I'm in the exact same position. LOLLLL!

  • @23Foxford
    @23Foxford 11 лет назад +4

    Love his videos, but his idea of fun with friends can result in pretty awkward situation

    • @brightface5005
      @brightface5005 8 лет назад +2

      i wonder if you would reply to this

    • @yiumyoumsan6997
      @yiumyoumsan6997 4 года назад

      @@brightface5005 I wonder if you would reply to this.

  • @erikm9768
    @erikm9768 8 лет назад +23

    Jesus what a mess. Also, i was hoping to understand how pressure actually affects archimedes

  • @arfaouiarij8938
    @arfaouiarij8938 6 лет назад

    I'm confused why you never spoke about the force of gravity ?

  • @usersersandrenfcgami
    @usersersandrenfcgami 4 года назад

    why did he ignored the weight of the cube when calculating the net force ?

  • @arulselvan4067
    @arulselvan4067 5 лет назад

    Buoyant force is the same as upthrust right? Sorry my English isn't that good

  • @sheme110
    @sheme110 4 года назад

    Isn't pB also acting downward not upward?

  • @rachellepangilinan5201
    @rachellepangilinan5201 2 года назад +1

    We have a kid typing

  • @Henryy97
    @Henryy97 9 лет назад +5

    i love you.

  • @eniamrahc73
    @eniamrahc73 6 лет назад

    I love you so much.

  • @Makedonche
    @Makedonche 14 лет назад

    @reesejpuc I'd go for the sal.

  • @midnightsilverpuppy
    @midnightsilverpuppy 7 лет назад

    That's interesting

  • @yashilakra5474
    @yashilakra5474 7 лет назад

    The voice is very slow

  • @sheu_her
    @sheu_her 7 лет назад

    Thats is not a P, please

  • @yashilakra5474
    @yashilakra5474 7 лет назад

    The

  • @jaggitsingh9892
    @jaggitsingh9892 3 года назад

    i just dont understand....i am in 6th grade and my mother makes me learn these things....... lol

  • @Somali_omega
    @Somali_omega 11 лет назад

    not what i was looking for mate. Salman can do better

  • @samiyahshua
    @samiyahshua 7 лет назад

    #flatearhclues #flatearthproof

  • @kenneffy1
    @kenneffy1 14 лет назад

    woah. lol

  • @samiyahshua
    @samiyahshua 7 лет назад

    #flatearthproof

  • @eslamnoaman3802
    @eslamnoaman3802 6 лет назад +4

    why we don't say that pressure at the top is equal to (roh+g+h+p atm)?

    • @ahsansafeerbiology
      @ahsansafeerbiology 4 года назад

      It's a vacuum I guess

    • @benricosimamora3429
      @benricosimamora3429 4 года назад

      (in case someone is still confuse about this). the pressure that was mentioned must be gage pressure (not absolute pressure) which is relative to atmospheric pressure, so we dont need to add p atm.

    • @predatorgaming895
      @predatorgaming895 3 года назад

      @@ahsansafeerbiology no gauge

  • @Perrihan
    @Perrihan 5 лет назад

    Thank you so much!