Archimedes principle and buoyant force | Fluids | Physics

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

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16 жыл бұрын

Introduction to Archimedes' principle and buoyant force. Created by Sal Khan.
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Пікірлер: 119

@arnoldchristian9501 7 жыл бұрын

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

@artakisthebest 12 жыл бұрын

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

@laputahayom 15 жыл бұрын

wow you just made so MUCH SENSE you have a gift for teaching. that never made sense to me before. thank you so much

@joeymama648 10 жыл бұрын

his voice is SOOOOO relaxing

@sehmio 7 жыл бұрын

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

@MandaNovokmet 6 жыл бұрын

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

@anber4129 5 жыл бұрын

Beautifully done. Very easy to follow. Very flowing.

@kanaeroseweld2237 Жыл бұрын

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

@NilanjanaLodh 13 жыл бұрын

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

@ModernWoodShop 6 жыл бұрын

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

@the_unconscious_mindthe_le3344 6 жыл бұрын

Maxwell Gunter 😂😂😂😆😃

@Ndfull Жыл бұрын

@@the_unconscious_mindthe_le3344 1qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqquq

@Ndfull Жыл бұрын

@@the_unconscious_mindthe_le3344 0000000

@nenoo1536 Жыл бұрын

this is actually really helpful!! bless you :)

@htavli 2 жыл бұрын

This video was very helpful. Thank you!

@TACZero1 12 жыл бұрын

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

@Chelsea-gs7qj 7 жыл бұрын

I usually love these videos but I'm literally lost

@keamorshedsoccer1382 7 жыл бұрын

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

@ArchmageMokokong 6 жыл бұрын

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

@artakisthebest 12 жыл бұрын

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.

@josemolina5423 6 жыл бұрын

Water molecule as a sphere? J. Dalton likes this

@niconikko 12 жыл бұрын

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!!!

@slmUSA 13 жыл бұрын

Thank you!

@sureshchandrapal2320 2 жыл бұрын

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

@abdosamr4639 2 жыл бұрын

Pressure acts in perpendicular directions, not in all directions.

@SwayamKrishnaartsandcrafts 7 ай бұрын

It has been 15 yrs but still this video helps

@unitelanka 8 жыл бұрын

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

@willpaisley7828 6 жыл бұрын

Does this assume the mass of the cube is negligible

@sergiomuniz350 6 жыл бұрын

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.

@BettyNalugo-et9sp 10 ай бұрын

so wonderful 💖

@Perrihan 5 жыл бұрын

Thank you so much!

@artakisthebest 12 жыл бұрын

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 Жыл бұрын

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)

@dst7ssa 14 жыл бұрын

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 6 жыл бұрын

woah you’re from the past

@ottavari746 6 жыл бұрын

Smokie Bear lol

@Aaliyah_Matyevna 2 жыл бұрын

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

@amirabbas0 Жыл бұрын

@@Smokie_bear9896 now you're from the past

@Smokie_bear9896 Жыл бұрын

@@amirabbas0 now i'm from the present

@ParadiXe311 3 жыл бұрын

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

@zainabhussain3887 3 жыл бұрын

😂

@firaolmulugeta9928 3 жыл бұрын

wow very nice i uderstand every thing what he says

@flimsyfox 4 жыл бұрын

I just had a "mind-blown" moment.

@psbbiaku640 7 жыл бұрын

hey sal I am ur no.1 fan

@hemantvaish5658 6 жыл бұрын

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

@bubbybumble616 3 жыл бұрын

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?

@tanviakhtar1527 2 жыл бұрын

Same😭

@megaelliott 15 жыл бұрын

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

@MellowCruisin 13 жыл бұрын

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?

@MitchelChabu-yl2xp 11 ай бұрын

You make me want to say I love physics

@stephenkong3155 7 жыл бұрын

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

@mousaalsaeed9410 7 жыл бұрын

what happened for weight of object ??

@specialparadise 6 жыл бұрын

Anyone else had a Eureka moment?

@ANUPAMAMATHEWPHD 5 жыл бұрын

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

@nolwazihlophe580 5 жыл бұрын

thank you

@kanikachaudhary6089 3 жыл бұрын

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

@SAISRIKAR2002 5 жыл бұрын

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

@Jay-jk7jv 2 жыл бұрын

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:)

@dravinashiyer936 5 жыл бұрын

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

@CcanCcaglar 13 жыл бұрын

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

@maxtan4471 3 жыл бұрын

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

@reesejpuc 14 жыл бұрын

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

@vinayseth1114 8 жыл бұрын

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

@amrshehab7019 5 жыл бұрын

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

@KavangWase 6 ай бұрын

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?

@rotflmaopmpqxyz 13 жыл бұрын

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

@himanshusharma9981 5 жыл бұрын

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.

@eslamnoaman3802 5 жыл бұрын

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

@ahsansafeer5246 3 жыл бұрын

It's a vacuum I guess

@benricosimamora3429 3 жыл бұрын

(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 3 жыл бұрын

@@ahsansafeer5246 no gauge

@amrshehab7019 5 жыл бұрын

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

@fablihakhan9265 6 жыл бұрын

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 6 жыл бұрын

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

@36sufchan 6 жыл бұрын

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.

@Ichneumonidae2 12 жыл бұрын

great video, thanks!

@drdkvetbiotech 7 жыл бұрын

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

@rjk368 6 жыл бұрын

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 6 жыл бұрын

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.

@DbzFighter02 12 жыл бұрын

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

@adas2922 10 жыл бұрын

thanks

@brightface5005 8 жыл бұрын

sisisisisiis

@sheme110 4 жыл бұрын

Isn't pB also acting downward not upward?

@arfaouiarij8938 6 жыл бұрын

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

@illiums410 7 жыл бұрын

Hotel?

@carlosnava8351 7 жыл бұрын

Trivago

@anotherdoseyt 7 жыл бұрын

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

@spatel6230 3 жыл бұрын

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

@fufuisgood 6 жыл бұрын

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 4 жыл бұрын

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 4 жыл бұрын

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

@usersersandrenfcgami 4 жыл бұрын

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

@SkyOnUrSide Жыл бұрын

ITS FREAKING 2022 it was 2008 dayum

@23Foxford 10 жыл бұрын

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

@brightface5005 8 жыл бұрын

i wonder if you would reply to this

@yiumyoumsan6997 4 жыл бұрын

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

@Henryy97 9 жыл бұрын

i love you.

@Makedonche 13 жыл бұрын

@reesejpuc I'd go for the sal.

@midnightsilverpuppy 7 жыл бұрын

That's interesting

@arulselvan4067 4 жыл бұрын

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

@starlight2620 7 ай бұрын

Yes

@LNasterio 12 жыл бұрын

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?

@taymrafid9139 3 жыл бұрын

My guy made the video before I was born lmao

@rachellepangilinan5201 Жыл бұрын

Good

@erikm9768 8 жыл бұрын

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

@eniamrahc73 6 жыл бұрын

I love you so much.

@gretawilliams8799 6 жыл бұрын

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, ....