03: D´Alembert´s principle and Lagranges eq
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- Опубликовано: 12 дек 2024
- Jacob Linder: Lecture 2, 11.01.2012, Klassisk Mekanikk (TFY 4345) v2012 NTNU
A full textbook covering the material in the lectures in detail can be downloaded for free here:
bookboon.com/en...
Prof Linder's lectures are excellent for their clarity, their pace and the detailed explanations. His notations on the blackboard are easy to follow and allow enough time to take accurate notes. The fact that he follows his textbook also helps in getting the most out of these lectures.
Thank you! I just joined graduate mechanics two weeks late and this lecture series may be the only reason I have caught up!
If anyone has a problem with his lecture or, if you are thinking, he is the worst kind of lecturer, all I can say, he is far better than ours in the university. Really, ours are the principle if there is a college in hell.
Thank you, sir. Your lectures help me a lot.
which university are you from?
12:48 the eq is principle of virtual work
Best lesson I found on yt about this topic so far, great job
PSA: Turn on closed caption at the bottom right of the video. It does a pretty job with 99% of it.
Can someone explain how gas inside a container has virtual work vanish? Why is the virtual displacement always normal to the constraint force?
38:56 Inadequate explanation and even worse, the textbook also omits an explanation!
Exactly! I am stuck on this part and it's bugging me since.
i think this explains it
i.imgur.com/2Sn1xzU.png
Here's the reason why: en.wikipedia.org/wiki/Chain_rule#Higher_dimensions
@@arviwot Thanks bro
Goldstein is not meant to be read. God help you if you try to learn from that book. I didn't understand it 25 yrs ago and I still don't under that book.
4:15 this means that virtual displacement is the infinitesimal displacement for generalized coordinates whereas actual displacement is with respect to actual independent coordinates, right?
Can I know what transformation equation means , and we are doing a partial differentiation then these coordinates are the variables of the function, and does the position of one particle affects other particle
It's a shame how despacito has 5 billion views and this masterpiece only has 65k
Come on, 5 billion people don't need to be physicists (although that'd be great). Not everything needs to have mass appeal.
It is not even an insightful explanation. Why the f is this a masterpiece?!
@@blzKrg exactly and no offense but dude just copies goldstein word for work so cant exactly call it a masterpiece
Quick Question which might sound trivial: At 21:02, why is v_i a function of (q_i, q_i dot, t)? Isn't v_i a function of (q_j, q_j dot, t) instead? For example, if we use the summation formula derived a little earlier, then v1 is equal to the the summation of the partial derivatives with (j) as the running index.
Just as r_i is a function of the entire set of q's and t, so too v_i is a function of the entire set of q's and also the entire set of q-dot's, as well as t. I think the prof, who I think is very good, is just using q_i here to represent the set of q's, etc. -- not meaning to say that v_i is solely a function of q_i and q-dot_i. (And note that the index i for a particular v_i is not connected in any way to any single index of the q's -- so it would not make any sense to somehow connect v_i to q_i, etc. E.g., v_1 can be thought of as v_x, but for polar generalized coordinates q_1 might be r or theta, neither of which have a unique or special connection to v_x.)
Can anyone suggest me a better playlist?
Am I the only one who thinks this is waaay too dark? I can't see the bottom half!
Good lecture, I appreciate but about the virtual displacement the example of a pendulum is not correct, in that example, the distance is actual but not virtual. For the virtual displacement the time taken will be zero..
What do you mean? virtual displacement is actual displacement without considering time right?
Hey from where we should shall solve the problem
Great lecture, horrible sigma's. :)
You need tensor notation where the Einstein convention kicks in. What is there right now is cringe-worthy.
What's with the audio? Sound is so low.
His is not using mic
20:21 chain rule
very cool lecture, im now at 18:45, but so low volume. I use headset and its hard to distinguish it if somebody talking near me. Thanks and hello from Kyiv.
23:00
what is companion
Advice: Use earphones to watch this video
20:20 it s called the chain rule not the product rule
+jackshephard90 it's called the product rule in some parts of the world
Lecture is good but sound is very less.
Audio quality is very low. I hardly can hear him!
Much appreciated for this video
He compares delta r with dr and also says that delta r is infinitesimal. However it does not have to be infinitesimal actually. It can be any value.
. 8:49
This is totally copied content although I have doubts in 4 places,
1. how did you brought virtual displacement ¿ri
2. I did not understand 2nd term at the beginning.
3. after interchange the value , how did you brought kinetic energy T.
4. When you were combining both values in D'alembert principal (where F-p) then why minus sign doesn't change?
anybody help me to understand.
Point 2 is where I get stuck
Thank you sir.
Nice explaination
Not particularly insightful, though it may help if one is getting stock in the steps of mathematical derivations while reading from a text, such as Goldstein's mechanics, say.
Magnificent
Sir pdf send kar sakte h iska
Ek website hai en.bookfi.net jisse Goldstein Classical mechanics ki book tum download kar sakte ho.
Very helpful. Thanks.
hes just writing exactly what's in the book classical mechanics by herbert goldstein on the board. You could just read the book instead of listening to this.
Understanding the symbols, and the reasoning behind the equations, is absolutely necessary for understanding what's going on. Jacob Linder is a teacher. He is teaching classical mechanics. What exactly do you expect him to be doing? No, he is absolutely not making this stuff up on his own.
I don't have a copy of Herbert Goldstein/s book handy right now, but I've got access to RUclips and I'd like to have a better understanding of this material.
What is your problem? Go read the book and don't listen in on the class. I happen to find it easier to sit in on the classroom presentation of the material.
+WildFire I just read this part of Goldstein's book yesterday and had some doubts. Professor Linder includes the essential information only and really made it sink in for me...
+WildFire If you don't like it then get the fuck out of here. Who is forcing you to watch this? This is free material available for the world to see and I am grateful for that. If you are not then just get outta here. I'll decide for myself whether or not I should just read the book or listen to this.
i got it for 200 inr lol
i got it for 200 inr lol
He makes me mad. He is smart, doesn't look like a nerd, not cocky, and generally seems to be a good guy. Can somebody find something wrong with him, please. Lol.
Seems like your inadequacies is bubbling up forcefully :) Forget physics, you need a therapist first.
he reads paper and writes them on the board then reads eq.
weird delta derivatives acting like total derivatives. total and partial derivative switch places as they want to, this is a math logic nightmare. L derivation and concept is hard.
The "delta derivatives" are virtual displacement. (infintisismal displacements with accordance to constraints under an instant of time)
Sound quality is very bad
Not audible
He is doing everything except explaining the lesson. Better to read a well written Mechanics book then to west time whit this kind of lecturer.
Stupefyingly boring. If there is a school in hell, he would be the headmaster
excelent-- but u talk very fast -- pls speak slowly-- thank u sir -- amarjit advocate delhi high court india
hahahah high court sey hahahah
And here I'm watching the lectures on a 1.5x speed 😅
this must be the worst professor ever...
Audio quality is very low. I hardly can hear him!