Watching this great lectures series during corona quarantine to enchance my intellect and educate myself in the meantime more.

Your service and dedication to teach every hungry mind is truly selfless.

Why am I watching this? Actually I'm a lecturer in medical school and I had a lecture on blood flow in blood vessels which is based on fluid physics and Bernoulli's rule I couldn't think of anything better to prepare for my lecture than watching your lecture on fluid physics it's a good thing that even doctors are watching your lectures Lot of respect professor From Iraq

Just because of you.... Today I can feel hydrostatics practically.... Great thanks to W. Lewin sir... Love from India 💕💖

You are the best teacher ever ! I really love your teaching ! I wanna wish you a long and happy life !! You are someone irreplaceable in my heart ...I wanna meet you so badly and say how much your teachings helped me ! Also I really loved your birthday series 💕 Thank you so much again professor Lewis!

Wow.i enjoyed every sec of this lecture. You are the best.

Your lectures contain all theory demonstration and application ,looking forward to binge watch all your content

This is the best lecture i have found on Archimedes' principle..just wonderful demonstration.

Thank you so much professor,... Very easy to understand with your demonstration...

Thank you so much for these meneer Lewin, ze zijn erg behulpzaam aan mijn understanding van physics

THATS HOW PHYSICS IS TAUGHT.....I AM COMPLETELY AMAZED...... EARLIER I FOUND FLUIDS VERY DIFFICULT TO UNDERSTAND BUT NOW I ENJOYED LEARNING IT IN THIS LECTURE......THE PRACTICAL DEMONSTRATION WERE JUST TOO GOOD.....

Thanks again sir... For the first time I have felt Fluids... Before this I had been thinking that in fluid part there is nothing but puzzles... Now I feel very comfortable in fluids.... Can't pay you against this but infinite respect will always be for you...

Dr. Lewin's ability to describe and draw complex principles is amazing.

Can't describe the experience, amazing Thank You🙏🙏

what a MIND BLOWING lecture

YES! I studied these exact same concepts, only to better understand them here.

another CLASSIC Lecture by Dr Walter Lewin :D .. great Demonstrations, Excellent Chalk Board Graphics.... Thank you.

44:55 "That's the reason she couldn't get it up. That's what Bernoulli does to you" - Lewis

Best physics teacher as well as the best physics KZfaq I've ever come across. No one else comes even close

This lecture is awesome. Thank you ❤️

Thank you, Professor Lewin!

Is there some intuitive reason for why the pressure is lower at a point in a fluid where the velocity is higher? Thanks very much for the videos.

47:28 We can all admire the greatness of the MIT chalks in this shot... no wonder why they sound so satisfying

How can he make the dotted lines so effortless? Pure skill!

I love each one of your lecture, each one. Thank you so much!

do you have any video on surface tension , capillarity and all that stuff

Binging bigtime on these lectures rn

Amazing lecture. And the rod he used in the water to explain stable and unstable equilibrium has colours of Indian flag. :)

I think that to understand the pool level problem, it helps being exaggerated. Consider a super dense object, 1 ton with the size of a coin. Now imagine we drop it in a boat that could carry it. Intuitively, the water level would rise significantly to counter the added weight. Now if we drop it in the water, there will be a massive weight relief in the boat and the buoyant force required to keep it floating will be therefore much less. The object has the size of a coin, so the volume of water displaced by it as it sinks is negligible and so is it's buoyancy. The total buoyant force that the water produces will be way less, and so the pool level will drop. As long as the boulder's density is greater than that of water, the same reasoning could be applied.

I wish I could actually sit there and learn these lectures from you

{39:00 -->} You said that when a hole is made in the vessel, water will flow with the same velocity as in the 'syphon case'. But what if both were done simultaneously ? The approximation that v2~0 would not hold good right ?

Wow! This is very interesting lecture.

That was one brilliant lecture!

In the answer to your waterline of swimming pool question, I think it will go down. When we seperate the stone from the boat, the waterline goes down more than the volume of the stone since the density of the boat is lower than the stone. So when the stone sinks the net effect is a lower waterline.

In which lecture surface tension and viscosity are included?

Love it.Thanks my professor.

This is all nice and stuff but the mind blowing part is 0:49

At 38:55, syphen experiment. when we suck the water at other end, we created a differential pressure at top and because of this water is raised to max height of tube. once it crosses the max height, gravitational P.E is converted to K.E which resulted into water fall.

Sir..its wonderful mind blowing and mesmerising and many more...

I remember this Archimedes problem from your video - Problem #29 (=

After watching your lectures I sometimes doubt my intelligence it seems like what the hell i have studied from past 2 years😂😂

Thank you so much, you will be remembered sir

professor i am from i india, i love to watch your lectures , you explain practically everything. i am in class 10 but i understand everything. it creates me a passion to get phd in physics .thank you professor

Whenever a body is partially or completely submerged in a fluid,it will experience an up thrust which is equal to weight of the fluid which has been displaced.

Just one word. Wow sir. What an amazing lecture. Wish I could meet you someday soon but it happens as if time doesn't allow,, but I'll change it. 😀. For the love of physics -Ayushman(India🇮🇳)

I guess the reason for the last problem being the following; when he turns the glass upside down a tiny amount of liquid runs through the microscopic gap between the glass and the cardboard with a high speed, causing so much low pressure thus the Mg of the liquid is supported. Please correct if I'm wrong.

Should the Navier-Stokes equation be covered for this chapter?

AMAZING!!!!

Dear Prof. Walter Lewin, The Ping ball- Funnel experiment was awesome. In case of inverted position (blowing down), what happens when the velocity is kept on increasing ? Will the ball fall down, stick to the top or stabilizes at level below the initial level ?

Always learn something new.

Dear Professor Lewin! I have a question about the syphon. Why fluid does not simply rip into two (at the top of the tube) and the one in ascending part of the tube come back to the tank and the other one in descending part go all the way down? Is it due to attracting forces between fluid molecules, which produce surface tension?

@22.22 what happens when i suck out all the air inside (vacuumed) that room? because the balloon has some pressure inside, will it explode? just curious. Btw I always enjoy your lectures.

In your questions about the boat and the rock, does the water drop to level ?! I concluded that, is it correct?

At, 35:08 P1

Sir, in case of siphon (37.18) will there be limiting value of 'd' so that water will come out through other hole...???

Um, King Hieron II was called a "virtuous man" by Machiavelli and he had a long and seemingly friendly relationship with Archimedes, and his father (a court astronomer) so he'd hardly "kill" him if he got it wrong. :P Great lecture.

Good work

wonderful sir

Is there any lecture on surface tension?

Amazing..

EUREKA is from REKA, rekao (sam) which on Serbian means Told (I told). Reka also menas river, flows of something, in this case words. It is similar as rhetoRICS, where Rika means roar (also talking meaning, but more in animal terms).

at 12:23, I know the high immersed of the boat after throwing the rock is definitely less than it before. So the waterline will go down comparing to the origin. Is it true?

sir in your earlier fluid mechanics video in which 5 meter hose magic was shown could we have even generated 0 atm with continuous block and inblow method

Hello Dr. Lewin, this is what I think about the question about the water level changing when you throw the rock overboard. I am a little confused on what you mean by will the water line remain change. Relative to the boat or relative to the walls of the pool? Initially, the water is at a height y_0. The volume of the fluid V_water is given by x*y_0*z where x is width and z is the thickness. For the boat to float, the F_b must equal the weight of the boat and rock. So F_B_0 = (M+m)g (1) where m is the mass of the rock and M is the mass of the boat. Now analyzing the situation when you throw the rock overboard. The mass of the entire boat-rock system must change because we no longer have m. So, in order to float, F_B =Mg. (2) So applying Archimedes Principle to (1.1) V_fluid_0*p_water = V_(M+m)*p_(M+m) and to (2.2) V_fluid*p_water = V_M*p_M . F_B_0 > F_B because of (1) and (2). Therefore. V_fluid_0*p_water > V_fluid*p_water. p_water = M_water/V_water = M_water/x*y_0*z so we have it that: V_fluid_0*M_water_0/xy_oz > V_fluid*M_water/xyz We know that the density of water must remain constant so as we throw the rock overboard, the mass of the fluid M_water increases. So if M_water > M_water_0 and the densities are equivalent, y_0 > y to keep a constant density so the water level will sink.

I am in love with physics just because of you. I left my job to teach physics..❤️

: . the water level is proportional to the weight of displaced objects = buoyant force ?

the temp. inside a balloon and in the surrounding air play a role on the buoyant force no? Is it caused by the expansion of gas increasing the volume thereby increasing the volume of displaced air or is it the temperature effecting the densities of the outside air and the inside air increasing the differential?

Good night Professor. Checking the deduction of Bernoulli's eq. at Resnick....it says that work at A2,P2,v2 (considering your drawing at 29:20) is negative because the force is opposite to the displacement. Why is this so? is it because we are working with a confined fluid? so it applies Pascal's law?

Hi Professor, I thought only if the glass is fully filled with juice can the cardboard stick to the glass, as 20cm of water can only produce a tiny fraction of 1atm. But I'm not sure what happens when the glass is half filled. Is it because juice and air inside gain GPE relative to the cardboard so the pressure decreases? Could you please give a hint?

at 35:00 do you mean fluid travels from lower pressure to higher pressure?????????

Thank you Dr. Lewin. raphael santore

This is gold.

Does it go down because the stone is more dense than water so while it is in the boat is displaces a volume of water equal to its weight but when it is thrown into the water it simply displaces its own volume.

Isn't coanda effect better explanation for the stability of the ping pong ball than bernoulli principle???

Dear Prof. Walter Lewin, How do you explain a boat sinking when a hole is put in it ? Is this because the effective density of boat goes up ? or The amount of displaced fluid goes down ?

5:26 how did he know about gravitational acceleration?

Sir , one more question, In a smoothly flowing water from a faucet, the water stream narrows down on falling . What force squeezes the water stream ? And how it is happening?

At 24:52 can we say that the pendulum moves to the left because of conservation of momentum ?

Sir, if something wants to float then it have to be less dense than the fluid that it floats in. So then how ships float if they are made out of metal which is denser than water?

Can anyone explain me the last part why it happened so water didn't come out?

"they will get some of their 25000 dollars intuition back"

43:00 what a prank!!

7:00 "Consider a spherical cow"

At 10 33, if the density (solid)>density(liquid), wouldn't then h>l ?? Which is clearly not possible.

U r mind blowing professor lewin

Regarding the Problem of the cranberry Juice!! If cardboard/paper Surface is 20cm^2 than from atmospheric pressure (100000 Pa) we get 20Kg (200N) pushing on the paper. Instead, inside the galss, the weight of the water can be for example 0.5Kg. So we have 20Kg pushing against 0.5 Kg for example. The air inside the glass is pushing on the water with atmospheric pressure but the total weight (air + juice) that is pushing down on the paper is the weight of the water: so much smaller that force produced by air pressure! Professor Lewin is this correct?

sir, i think that at 48:15, the juice didn't fall out because of the tension of liquid but nothing to do with the barometric pressure. The pressure inside the cup (air in cup) is as same as the pressure outside. Is it correct?

Here; the water level goes down because when the rock was in the the boat the displaced water, is greater then when t it through down.

I consider useful to present the "firefighters paradox": stop the fire or demolish the house? Because the force of the water jet displaces the bricks and other elements of the house structure. the brick floating (short time) on water flux. and as numerical calculation how much water I need in order to dislodge a brick (which force must have water to dissolve a brick) ?

i think the level of water will go down because after throwing the stone the total mass of the boat will decrease and the density will decrease too is the reason right?

I think the water will lower slightly. The stone will displace its volume of water when tossed in and therefore sink due to density. At this point I believe that the boat will float higher in the water and displace less. The boat was displacing water equal to the weight of the stone which is more water than the volume of the stone. If the stone was same density as water , the level stays the same.

Dear professor for me it was astonished, it's plead to u please let me know as we r always taking direction of acceleration due to gravity upwards or downwards only irrespective of what is the direction of external acceleration whether horizontal, vertical but g l never studied about horizontal direction of acceleration due to gravity as u mentioned in case of Apple and balloon. Please reply

How do you draw such dotted lines sir?

Under what conditions as space accelerated with the apple, the apple would go in the direction in which it is accelerating?

How did the cranberry juice not fall when it was tilted over in 48:00 min?

Professor pls solve a query why the level of water rises when we put stones in container filled with water.

At 20:52, when you accelerate the compartment in the upward direction with acceleration 'a'...................then for a person of mass 'm' inside that compartment, they will feel a fictitious force or a pseudo force which is 'ma' in the direction that is opposite to the direction of acceleration of the compartment...............so is the term 'ma' which you are referring to as "PERCIEVED GRAVITY"??

Sir, which physics books should I read?

so sir, do u mean that the ship's centre of mass should be as low as possible to attain maximum stability?

The demonstrations with angular momentum and torques were less of a shock to me than the helium balloon going against gravity. Never really gave any thought to why it goes to the perceived "up".By the way, if you took the balloon out of the case would it still go against the perceived gravity? If you accelerated it? Thank you for the lecture series.