Lecture 1 | Modern Physics: Classical Mechanics (Stanford)

[@tttzzz1957]

This Guy needs a nobelprice for beeing one of the best teachers the world has ever Seen

[@psychotic.hazard_5530]

I am 15 years old and for years, I´ve been so interested in Physics, I am practically married to it. I know it is really hard, and I´ve had tough times understanding some subjects; but through videos, books, and online lessons I am understanding more and more everyday so I can understand the subjects better at college. My biggest dream is to understand the nature of Physics and everything to it to be able to work professionally at it! I try to study everyday and these videos help me out a lot. I write down what I learn and look at my own notes from time to time! This is so much fun! I wish I could be sitting in one of those classes right now! I love studying and learning!

[@melontusk7358]

Thanks, pal. I'm currently studying Physics in college right now, specifically Analytical Mechanics. I have also been watching video lectures and reading your comment is really inspirational. I wish you all the best of luck in your future endeavors.

[@psychotic.hazard_5530]

Chip Mahgilify I know! It is absolutely defying and I know what I’m getting myself into. But I’ll give all of my efforts and trying will not be bad! Thanks.

[@psychotic.hazard_5530]

Elon Mush Thank you so much. Same for you. I imagine all of the hard work, mental and physical effort, sometimes even stress that you may be going through. Physics is not something easy indeed, but we will get through it and pursue our dreams I believe in you. You chose one crazy but awesome thing to study!

[@Code-ff3ir]

Exodus Scientific any other playlists, online classes and books you would recommend?😀😃

[@psychotic.hazard_5530]

Code 123 If you want to get introduced into some basic Physics, you can try a course in Brilliant.org; they have free introductory quizzes and their prices for full courses are pretty good ! They also have Mechanics, Quantum Physics, Maths, Theory of Relativity, Logic, Calculus, etc.

[@jwoya]

When I first saw this video, I thought that the whole business of transitioning between states was a very simplistic and academic exercise. But when you get to the next quarter, Quantum Mechanics, physical objects can be in a superposition of multiple states, and this understanding turns out to be hugely useful. Lesson: Don't question Susskind :-D

[@spectrumofreality]

Everything is a wave always there are no particles. Superposition is just the manifestation of this...

[@Y_M_Alhamdan]

From 00:00 to 11:59 First he speaks about deterministic. He defined it in the following way: wherever you happen to be, you know exactly where to go next, so it's deterministic into the future. I.e. wherever you start, you know where you will be arbitrarily into the future and also you know where you were before. From 12:00 what kind of laws of physics do we not allow? Classical Mechanics forbids a system that has a deterministic from one direction and not from the other (e.g. possible from past to current but not from current to future). How do know if classical mechanics is allowable deterministic? Just check if each node has degree of income equal degree of outgoing. From 23:00 How much do you need of states to say what happen next? This brings us to continuous physics. Systems in classical mechanics are deterministic and reversible. Besides, systems could be infinite of chains of states or cycles. Conservation Law is just memory where we started. Information Conservation is the one that you never lose memory where you started. Information Conservation is perhaps the most fundamental law of basic classical physics. 32:42 1st order equation means it has only quantities of 1st deterministic with respect to time. 41:35 give a good example of Head and Tail. This video until this moment takes 1006472 views, so I expect that the second lecture would be half of this number of less? Why? I don't know but nature behave like exponential way. Let me check it now. EDIT: I just checked, it is 312134 views As I expected. I think the reason is people come to do the first step, but few who goes for the second step, and fewer who goes for the next step, etc.

[@meowwwww6350]

You're a treasure

[@NeerajPal-phy]

Sisyphus problem

[@malissa456]

wow it's incredibly generous of stanford to offer these to watch!! thank you sooo much!! bless you.

[@yourlifetrulymatters]

God bless us, indeed.

[@commissarmethyst]

Stanford lectures let me learn academic subjects while being stuck in Russia without any proper systemic education in existence. Thank you very much for recording and putting them, I wouldn't be able to learn certain things otherwise.

[@wayneyadams]

These video lectures should be required viewing for all Physics Teachers at all levels. I watched them when I was teaching Physics just to see if there were any pointers I could pick up to make my classes better. Now I just watch them for enjoyment.

[@raincloud763]

I'm gonna listen and study all of 136 lectures by professor Suskind. This is the first step I take. I hope this wonderful journey will take me to whole new level of understanding physics.

[@Explodingtv6Q]

did you finish it?

[@duckyoutube6318]

@@Explodingtv6Q not likely I would compare the amount of views of this video to others later in the series and use that to estimate if this person continued to watch. If the 120th video has only 10% of views this one does i would say there is a 90% chance this person didnt continue the series.

[@adrianapuch5527]

I remember me watching this at high school barely understanding anything and now since i started studying phisics in my country im so glad I know so much of what he's talking about

[@xelionizer]

Especially when he starts talking about the derivatives regarding F=ma ;)

[@anarchyxskamfull]

I love you 😘

[@pleiadian]

I just want to say that I am so grateful that these lecture series are made available. They are very very helpful.

[@ggibney0856]

I cannot thank you enough. I cannot afford an education at Stanford (or any other great university or even not so great university) and the knowledge I am learning from Stanford/Leonard Susskind is one of the greatest learning experiences of my life and hopefully I can take this knowledge and change the world for the better .... at the very least it will make my world change exponentially with every lesson here.... THANK YOU SO MUCH !!!!!

[@ripperduck]

Hate to say it, but these lectures are FAR, FAR better than the ones that I received at my uni. There, all my profs did were to throw a bunch of DiffyQ's, formulas and proofs on the board, and rarely ever explain, or LECTURE, as to what they meant or why they were useful. Despite the fact that I have a BS in Physics, watching Dr. Susskind's vids tells me just what I missed. What a great teacher will do for a subject, he's filling in so many holes in my knowledge...

[@ulalaFrugilega]

Thank you so much for posting this, o Stanford! This is true science for all. What wonderful spirit! And also very many thanks to Chaz Shand for taking the trouble to put them in order.

[@Kuoted]

I love these videos. Once you start watching it you can hardly stop, anything discovered is much greater than the time wasted on playing games or watching other junks.

[@ksai7593]

Sir are you still alive ? ( No offense just curious)

[@TheElectromagno]

Perfect class . It goes deep into the soul of physics.

[@switcheroo12345]

Currently 13 and studying this to learn how I could make possible jet engines and understand fully how motion works. Very helpful of Stanford to record these lessons.

[@stanleyhe8075]

This has got to be one of the best lectures I have ever seen.

[@aerodiana1988]

How amazing it is to find physics lectures for free!!! I get to learn something new in my free times :)

[@crazystemlady]

Happy learning to you! Im in university physics and hoping to get a better appreciate for physics for the standford biology and mathematics playlists were so inspiring! Not just the material but the little personal anecdotes made by the professors!

[@chanpreetsingh007]

All to need to remember is a). classical mechanics allow unique paths to past and future. b). Information about the system is memoized so that integrity can be maintained e.g conservation of energy, momentum etc c). We need infinite amount of information in order to predict with great precision through out the time.

[@foundingtitan9759]

Can you tell all of susskind’s lectures which are available on youtube(about 193) are these bachelor level or above that,I have passed class 12 in India When can I watch these.

[@shebotnov]

thx for great and free lectures! Coming from computer engineering background you recognize state machines in the beginning of the video. Thats so awesome that science is interconnected. The more you learn about physics / chemisty / math / computer science the more you realize its fundamentaly the same laws and rules

[@conjmcnal]

Just seeing now and that's the first thing that hit me

[@wagsman9999]

Highly recommended, Prof. Susskind explains things very clearly. Definitely a higher level physics course. I took engineering physics years ago but the more abstract concepts (e.g., the Lagrangian and Hamiltonian formulations) were never developed. If you dare take these, bone up on basic calculus chain rule, integration by parts, and partial differentiation. Next, quantum mechanics (shiver me timbers). Oh, I saw his book in the public library looks like a good read, The Cosmic Landscape.

[@Sidionian]

This was a great Lecture, Dr Susskind. Thank you very much, it was very enjoyable and valuable. Finally a guy who just talks plain old fashioned sense and knows how to weave that in with the conventional physics syllabus. Take note other teachers/lecturers: Always know how to move from the general to the specific, from the big picture to the smaller picture, AND NOT THE OTHER WAY AROUND!!! This lecture is a good example of that. Very well done and enjoyable.

[@rohitraj4275]

If I can attend even a single class from prof, I will experience heaven . Hope I can experience heaven in this life.

[@rtt1961]

Combined with his book of the same title, these lecs are a gold mine.

[@Hegeleze]

533,675 views for lecture 1, 37,220 views for lecture 9 which means about 7% make it through classical mechanics...

[@sephirothjc]

Hegeleze nobody said it was easy

[@morganmckenzie1303]

+Hegeleze That sounds like the correct drop out rate. How many students did you have in 101 that made it all the way to 400 levels? If i recall correctly EEs have about a 60-70% dropout rate. I'd hazard a guess its the same for any hard science. It's almost always the same reason too, they can't do the maths needed.

[@DavidVonR]

+Hegeleze I made it through classical and quantum mechanics. Forgot almost all of it.

[@MrPoutsesMple]

+Hegeleze Assuming people watch the videos in series rather in parallel.

[@maxm.5802]

+Hegeleze it could just mean alot of people rewatch the first lecture or two as a refresher

[@caubeviet]

Cool ! i'm Vietnamese - i can't go abroad to learn - so that it's usefull. It help me have more experiences. Thank you so much !

[@YouGoByeBye]

This man is very intelligent, he puts it in simple terms, that even I can understand. I'm 18 and in high school, still at the time in my life where I never thought math would be interesting, but this is an exception to that rule.

[@lamda3s634]

Dr Susskind is Perhaps the Most Revered Theoretical Physicist, Professor Educator. of His Time! thanks Doc For the Legacy Videos they will Rock for all Times..

[@RemedyCabinet]

Hey, this is not a bad place to start - with Leonard Susskind's lectures, but I have just finished - at nearly 30 years old - studying IGCSE's in Maths and Physics. I was worried that after well over a decade out of school that I would struggle, but that level - GCSE - is the perfect level to start and get the very basis of Classical physics. Also, the maths is just as important to understanding it all. Hope that helps.

[@PersonallyOptimistic]

Wonderful that we have such a course free and available to all. Thanks to Leonard Susskind and Stanford. Hoping to refresh my ailing Physics knowledge!

[@francescos7361]

Thanks prof. Susskind for sharing your studies.

[@cltmzs]

This makes me miss when students weren’t scared to openly ask questions in class

[@ibrahimrahman2509]

Susskind is the best at explaining. Period.

[@garrettwilliams11211]

The mass of the earth can be measured indirectly. There is an equation for g that involves the mass of the earth so the problem of determining the mass of the earth comes down to measuring G and g accurately.

[@benbencyben]

This Prof.is amazing. He actualy teaches you to understand things better and esier!!

[@natalialarkin]

I'm currently 12, and I have always loved physics. When I saw lectures by Leonard Susskind, I jumped at the chance, since I'm reading a very interesting book by him. It's called "The Black Hole War" if anyone's interested. I highly recommend it.

[@SalsaTiger83]

A simple point about predictability versus deterministic: In chaotic systems small uncertainties about the starting state amount to big differences between prediction and what actually happens quite fast, so that after a short time, predictions are not useful any more.

[@wwaqashussain]

Thanks , Stanford University.

[@shawonsarkar101]

this is the best gift (internet) that humanity has got.

[@jamesdowns72]

14:46 Susskind: "Why are they forbidden by the principles of classical mechanics?" Someone interrupts him and we never get to hear this question answered.

[@md.omarfaruk89]

Because the process loses information about future or past which is not acceptable.

[@rukna3775]

@@md.omarfaruk89 not about future, but the info about the past position

[@nomachinesinthisroom]

That frustrated me soo much!! He was on a roll...

[@sandeepupadhyay7165]

The lecture gives a detailed understanding of the basic axioms of classical mechanics, why do we have two dimensions in phase space and that too position and velocity only. Very interesting and helpful for those who want a grasp in the field

[@judy548]

Sandeep Upadhyay e

[@TheTruKman]

This is physics in 2-D when referring to a 50/50 possibility. You just added area, lots of crazy calculations come into play then. Calc 2 and Phys Chem will let you answer that.

[@ripperduck]

I viewed one of Prof Susskind's lecture in which he stated that all physics depends on a change of energy. My hs physics teacher said the same thing way back. When I study physics now, I keep this in mind whenever we study any concept....

[@multicultures]

knowledge is something that should be seen as an opportunity it is so sad that many ppl have the opportunity to learn all they need just by looking everything up online but instead they waste their time on petty things and never try learning just for the fun of it.... back 100 or so years ago videos being free like this would be like finding gold

[@jonwacken4312]

"Leave Sauron to me!" - Leonard Susskind

[@RemedyCabinet]

Thank you Lenny and Stanford for all these lectures.

[@maurocruz1824]

This guy rules. A true physicist,

[@mechwurm]

man this is cool they decided to put these on the internet. That would be cool if Harvard put their physics lectures up.

[@tgizzle829]

the equation describes an energy mass duality, it is not a vector or in other words an equation that you can apply a variable of time in it to figure out it's direction, the equation may apply to all matter

[@zhongruiwang]

His approach to CM is really unique and impressive.

[@justmeduhfull]

Great lecture, I love how you explained it in such a simplistic way.

[@HopeGenesis]

Thank you for this!! I am spending this year studying alone to get into university and these lectures are great!

[@onion77478]

I'm 2 years old and completely get this, im posting a comment about how young i am so that i can be validated by strangers about how ahead of my age group i am =]

[@CressyTV]

"Conservation laws" seem to be based on determinism (classical mechanics), in that unless there is "random" in the system (could be either as each is free from strict causation) then the past (and future) must be predictable.

[@jefflee4001]

There are conservation laws in quantum mechanics as well.

[@disregardingsanity2890]

Determinism as he said works in a very finite measure of time and closed system so long as you're equally as precise. However, if you increase the time interval, then you have to proportionally increase degree of precision or errors go wildly out of control. He also mentioned that in the real world determinism would fall apart due to the aforementioned chaotic nature of...nature. That's where Brownian motion and Mandelbrot sets begin to become applicable. The term conservation simply means that any information (objects or events) aren't lost from initial to final measurements. Ergo, predictability is limited to precision of time, number of objects and their respective states.

[@jarekkul]

Nice lecture as an explanation of the need of the phase space and deterministic bases of classical mechanics. One can say that In classical electrodynamics when a charged particle moves with acceleration it radiates energy and semiclassical force is related to the first time derivative of acceleration. So from lecture arguments the phase space in that case should contain also acceleration ...

[@drumstruck751]

The vacuum of space is rising the external kinetic energy of earth while in the system we are dragging our own potential energy down by having complexity to the system while at the force of which the vacuum expands is at which the planets want push back at the vacuum around but find no circuit for physical matter in thus finding reasoning for gravity itself.

[@ripperduck]

Acceleration is a change in velocity, meaning that there is a change in energy. Only with a change in energy do we have a physical change. If we have no change in energy, then we can accurately predict where the mass will be in a given time. That's what he means, we don't need acceleration to know where that particle will be, mainly because acceleration doesn't exist until an outside energy source comes in and messes up the initial state, causing acceleration....

[@SeAn-jr6ht]

I once saw his book. It was awesome.

[@Tgrass720]

strongly suggest you watch all these lectures at 1.5 speed! :)

[@ahmadyfh6186]

Thank you for saving me 1/3 of my time lol

[@benjamincox6299]

Hmmm... I think I will watch it in 0.25 speed because I enjoy the pain!

[@zebunker]

Go away

[@mickey_slipz]

Wonderful teacher. Although I keep thinking about how Mr. Susskind has the face of George Carlin, and the voice of Christopher Walken. I will continue to watch the videos.

[@sephirothjc]

I love this video. Have you considered teaching the number of observations needed with lines of psedocode, something like 'if state_n = a, state_n+1 = a', I find it easier to think of it that way instead of the arrow diagrams, but maybe that's just me.

[@gives_bad_advice]

Wow. All this just sitting here on You Tube. . . What a find!

[@Explodingtv6Q]

interesting, never knew about that, now that I'm taking studying physics more seriously than before I realized that I knew so little before. ill still be studying more about this, ill watch all the videos and take notes

[@xoh_spaceboss]

Am I wrong? The example at 45:00 should have been HH, TH(HT) TT. He let these students mess with him when it came to TH and HT, which are the same thing since theres only two options to land on. Starting TH or HT doesn’t actually matter no matter how many times you flip. The second you add more than one option you can’t for sure predict.

[@JonathanMutsinzi1998]

I was thinking the same thing…

[@fielsjd]

@sdv711 Is your confusion regarding why you can't differentiate the initial x coordinate to determine the velocity? If so, here's why: the ability to differentiate the x coordinate is contingent upon a continuous model of the x coordinate with respect to time. The problem here is that with no initial velocity, you can't build that model.

[@friendlystonepeople]

Best use of Internet. An amazing lecturer and of course a great physicist

[@anon8109]

Thank-you for this series! It's fantastic.

[@commentOshimasu]

He's a certified genius. These proud clowns insist on trying to appear intelligent by asking the silliest questions and fail miserably each time. It's a privilege to be taught by Susskind. You are not supposed to try and outwit the man in mechanics 101.

[@s.v.discussion8665]

You can't see the damn power point slides in this class. This is good!

[@elocekkab]

The teenage Stanford physics majors don’t understand “the simplest universe I could think of” Astounding.

[@outside8312]

Who?

[@jenniferlaflora3293]

33:43 the force, sound like the frost perhaps precipitation has some frost 33:43 I’m mean it sucks to remember that word about photosynthesis but the speed of light is what makes that force is that a wrong answer ? 33:43

[@drumstruck751]

If you put nothing into something the matter's potential energy converts into kinetic energy. If you put something into nothing the matter's potential energy actually rises. If you put matter into matter the matters potential energy lowers.

[@hirak99]

At 42:43 someone asked to "switch the second one", which was unnecessary and created a mess, only to be corrected later on by taking an alternative route at 45:20.

[@JesterGren]

@acr08807 "to begin" is a concept which alone makes sense without time. However, beginning is something that doesn't make sense unless it is framed by time. Began, begin, will begin all have no meaning without time, so with there ever being an instance without time nothing would be able to do anything, including begin. To put it simply, verbs happen in time.

[@Hybridspasser]

I think you misunderstood it; it was actually a quite simple, repetitive motion: HH >H (as in HHHH....) HT > H (as in HTHTHT...) TH > T (as in THTHTH...) TT > T (as in TTTTTT....)

[@SevenFootPelican]

Thank you Leonard. You renewed my interest in the nature of reality and the universe. And trying to get to the bottom of what this "thing" we're in even is. Thank you, thank you, thank you

[@yourlifetrulymatters]

God’s creation really is bizarre.

[@خالدالاسدي-د5ر]

Hello , I have a question . I am an electrical engineer , now I work in power transformer test when I make lnsulation resistance test between windings of transformer or between winding and body there are three type of current will appear 1- capacitance current 2- resistive current 3- dielectric apsorbtion current My question is what is dielectric apsorbtion current and the behaviour of insulation when this current pass through it ?

[@MattOGormanSmith]

I realised I really need a solid grounding in calculus to follow it properly, so I watched Calculus 1 by UMKC's Professor Richard Delaware. Now I'm back for another go :o)

[@ArsLumen]

The Black Hole War: My Battle with Stephen Hawking to Make the World Safe for Quantum Mechanics by Leonard Susskind is a good book to read to get some background on the lecturer. He mostly studies general relativity, concepts in quantum gravity, and formulation of relativistic problems in string theory like black holes. In the book, he tells like his background, life story in relation to several physicist including Hawking, and his theoretical contribution to black hole theory.

[@projectbeard]

@tonymajjc 1) whether the bullet kept going would depend on how fast the bullet was going. 2&3) the moon still has gravity, it just has less of it than the earth does. so the bullet would act the same way as it does on the earth, only it wouldn't need to go nearly as quickly to escape the moon's gravity, due to the fact that the moon has almost no atmosphere (less atmosphere means less friction) and less gravity than the earth.

[@fielsjd]

@sdv711 His notation is incorrect when he writes that. It should be dF/dt = m*dv/dt ( or dF/dt = m * (d^2 x/ dt^2)). The mistake is tacitly corrected when he erases the space derivative and writes it as dF/dt = ma.

[@saurahraj123]

very good explanation of classical mechanics which comparises mainly of nutonian mechanics i loved the vedio.

[@adkinsjr]

I don't think he has covered that yet. I read in a physicforum that there is a course on SM that will be posted.

[@lawanbrown16]

In the last Law bit the correct sequence was HH toH, HT to H, TH to T, and then TT to T

[@ohmysausages]

I think the Very last sentence about third derivative equations is very important. I really think that is the future of physics.

[@BioPhys92]

There are a lot of interesting concepts just in this first lecture

[@MrBrew4321]

In the universe with both heads and tails possible, if you had a way to measure the state of the universe and it only ever read heads, you might think your state space was the first universe (only heads). How can we know our universe doesn't have hidden state space that is either hard to access, or impossible?

[@MonsterSlayer14]

This Prof. is amazing! He actualy teaches you to understand things better and esier. :D

[@ms.550]

11:23 10 minutes into the lecture and I'm already thinking, doesn't make the whole universe deterministic, since every event can be traced back to its cause, sure there can be other causes too and the system can be too complex.

[@DamnBoiya]

Hi, I'm Carum Phull and I am going to take this lecture series. I have studied Science. I look forward to your wise words. Also, a big hello to Stanford, I love free learning :). Kind regards,

[@SpeaksYourWord]

Good luck. Are you going to follow some books with this?

[@dedanoe]

you begin with lets observe physical system against time without defining what the hack TIME is making all your physics laid on undefined magnitude of great significance (time). if the battery of your watch is empty then time according to your perfectly functional watch is on stand still. it is alike the case with libra... what actually does it measure force or mass cause g = 9.81 m/s^2 is the same on the earth surface.

[@ahmedalkabirnadim2975]

33:44 : Why is the force dependent on the position? From where do we make this assumption?

[@Secretname951]

This is kinda fun and not so hard so hard! Maybe I should be at Stanford 😅

[@Secretname951]

Ok, it got harder when started talking about orders of the laws of physics and how that changes the dimensions of the phase space, I’ll need to spend a little time playing around with that…😂

[@jamavo]

the universe does not have weight, as weight is mass under influence of gravity. The thing that stays the same is its energy. The earth has less mass then when it was 'created' (watch out with words like that in objective physics), as part of our atmosphere escapes over time. Also, the heat that is emanating from the earth's core is lost mass, as energy equals mass (E = mc²). It probably gains some mass from dust in space falling to earth under it's gravitational field, not sure how much though.

[@superoriginalname]

I completely agree..this is like finding Salomon's Book of Wisdom

[@drumstruck751]

to reiterate the vacuum is expanding because mass wants to expand but can't so the vacuum itself does it for us pushing all that energy directly back at us. To say the force of the world that's pushing on the vacuum is literally throwing itself on every piece of matter within a planet's system.

[@Lordradost]

@tonymajjc Air causes that friction. Like wind, there is actually a density that is very observable, gravity pulls (like a universal magnet: gravity). (But please, try using Capitals, comma's and (.) like when you talk. You can't hold enough air to say all that without stopping. ;) )

[@Liaomiao]

Hmm the concepts here seem quite advanced to me. I self taught myself up to vector calculus so I understand pretty much all the maths here, but I'm having troubling following the concepts at this abstract level. Perhaps one or two more specific examples throughout the course would have helped me greatly.

[@Domispitaletti]

The expression of despair in his face with the dumb questions they make..

[@Horrortelltales]

My name is Will Hunting Jr. I'm just studying QM because it's fun. Anyone similar?

[@ЧерныйКот-х4ь]

Same here

[@90sharn]

why would you state your name? lol

[@torresfan1143]

Good , Will Hunting

[@madhusudanjeurkar3178]

Me Too!

[@torresfan1143]

Sharn Lain It's a movie reference