Physics 68 Lagrangian Mechanics (3 of 25) The Partial Derivative W.R.T. Position 

Outstanding! Instead of using bizarre examples like cycloids of balls rolling down oddly shaped hills like cycloids, you are giving introductory physics examples that can be easily understood by people who haven't had physics classes in a while. Thank you so much!

i like the way you split a big topic into simple and clearly understandable 5 minute videos....keep up the good work !

Tank you for posting this !!! It has helped me out massively ... I find lecturers tend to rush through at a million miles per hour so I am so grateful you have done it in small sections !

This concept is totally mindblowing! I love it! Also brilliant teaching!

Born teacher , aproaching the best way to the problem , also very knowledgeable , every field in physics knows to its foundations, my brother learned for an exam in fluid mechanics , im learning in advanced mechanics ... God bless you

I like the way u teach us which gives complete clarity during the lecture

I came to the Lagrange method because I am reading through structural dynamics and aero elasticity. Advanced mechanics are often introduced too briefly for me. Here it is very nice step to step approach to unfold Lagrange ideas. I immediately think of simple harmonic motions, provoked by this series videos. It is really not simple and they are analyzed at different level of methods from high school physics to a master degree program.

thank you for doing these advanced mechanics and e&m videos they are so helpful!

I have learnt a lot in this classical mechanics lesson. L=T-V, Thanks. Waiting for Hamilton's Equations of motion

Since kinetic energy does not depend on position we know that the derivative of L with respect to position is just the negative derivative of potential energy. And since we know that by definition potential energy is defined as the integral of force with respect to time and that differentiation undoes integration these results should be very obvious to anyone with a solid background in Newtonian mechanics and Calculus.

Consider F=ma for a body under acceleration. By analogy, for an electron accelerating within an electric field, surely F=qa? Would you not agree? But because an electron also has mass, there may well also be a component of force due to its mass being accelerated within the same electric field. So surely then, Total Force = ma + qa = (m+q)a? When we use the Hamiltonian in solving Schroedinger's equations for an electron in an electric potential -for example in a Hydrogen atom, we DON'T (if I remember correctly) consider similar elements of total energy within the Hamiltonian, seperately (ie: Total energy arising from position and motion the charge of the electron within an electric field PLUS the kinetic energy due to mass of the electron under motion). That is, we CONFUSE the two into one, within the Hamiltonian. What I mean is, when we solve Schroedinger's equation for the electron in a Hydrogen atom for example, our total energy is given by an equation which confuses effects due to the mass of the electron with effects due to the charge, to provide total energy in the Hamiltonian. In my view therefore, the QM taught to us at school and by extension, the work of Schroedinger himself, must be wrong (incomplete)! It also suggests, Newton's Laws are incomplete: Consider if it was possible to concentrate charge into a point, a hypothetical particle that is a pure charge with no mass. Surely that particle will experience a force in an electic field which will be given by F=qa. Applying Newtons's equation would suggest there will be no force. When modelling the electron, we should therefore regard it a a superposition of a pure charge with a particle of pure mass.

These first three videos are great! I can't wait for the rest!

I owe you all the money I ever make after graduating 😂

you are great i like you.. More vedio of this proferor please

Mr. Biezen your lectures are really super and very lucid. I wish your videos on physics continue to clear many tough topics in physics such as this for a person like me. I request you to put videos on basics of classical mechanics such as what is generalized coordinates, degrees of freedom, constraints etc...Thank You..

Thank you so much for this videos. But, I am not too sure about that columb's law. I think there is supposed to be a ➖ in the final equation.

Wow.. You really explain it well.. Thank you very much..🌹

Thank you for the good work. Could you make some video about D'Alambert principle and Kine's principle about virtual Power.

u were awesome when i saw u first ..and u will be the awesome as u really are ..

it really is a solid explanation, I would only add that dL/dx is essentially a gradient of a scalar potential energy field and it therefore must be the force "field" for the system. That makes dL/dx easy. The other part d/dt of dL/dv is not quite as intuitive.

Wow , so simple! Thanks

keep them coming! these are great lectures

Can you do a video on inverted pendulum please?

Just amazing what a way

Thank you Michel.

I am really thankful for you💜

Hi Michel - I am enjoying your videos. As a chemical engineer, I often wondered about mechanics, so thanks for your videos!

error at 1:35. The acceleration due to gravity is -9.8, not +9.8. Otherwise antimatter being negative has been created.

can you explain me why we are taking T - V .why we are not choosing T +V,

So, force (dL/dx) points in the direction of increasing "free energy" (T-V) ?

I love this, but why are we not taking the time derivative or the partial derivative with respect to x dot??

Thanks for your Videos,they really helped me lot. But some of your examples are not so complicated as i've learned from the University. could you please make some more challenging examples,because the problems from the exams at the universities are more difficult. Such as virtual works by using d'lambert Prinzip in connection with lagrangian some sort of these.....

thank you sir

Thanks a lot.

Many thanks

like this so much, very helpfull

Insightful

Professor, why does this feel circular? How can KE and PE be defined for certain scenarios without using force (and by extension, acceleration) as their basis. Surely, we cannot just assume that the PE of a harmonic oscillator is (kx^2)/2 without using the line integral definition to derive it from Hooke’s law.

so helpful

Superbly communicated. Many Thanks👍🇨🇦

Brilliant and accomplished thanks 👍

Thanks sir

My God. It is amazing. Thanks a lot.

Thanks sir❤🙏

مرحبا ان من العراق هل استطيع التواصل معك انا طالب ماجستير علوم فيزياء بحاجة إلى المساعدة

thnks

1:35

👏

Simplified the topic af

nice

Rahmat 😀😀😀😀

there is not subtitles...

Professor I have a doubt . Generally we write potential energy is equal to kinetic energy for energy balance. Why L is not zero in our case?

Who else is in high school watching these?

These videos are helpful but blurry...

Bien!

I love u

1:35 apparition of ghostly orb on right of screen. :-) Yes I know it's only a reflection...

1:00 I think you forgot the square

It's nothing but F= -(gradient)U

Classical Mechanics => solving problems is like building a house with a shovel, a hammer, concrete and wood, it works, but takes some time Lagrangien Mechanics => solving problems is like buildind a house on a computer, and machines build it. Conclusion : Newton => genius Lagrange => genius

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The high pitched beeping in the background of the videos always throws me off

Thank you