Dear Professor Lewin, I am responding to your comments about people posting answers they have taken from the internet. I feel your disappointment and how it challenges your will to keep going, please don't be deterred by such action. I welcome your challenges and work on them assiduously - I got the main structure of the tunnel answer correct but fell down on the mathematics and recognition of correct application of formulae. I don't post as I am aware of my limitations - mainly my being unable to deliver a credible answer - but I do then go back into your lectures to work on the gaps the problem has highlighted. So, in short, there are probably many like me who are (until now, in my case) invisible to you but who are diligently using your problems and lectures to improve their knowledge; keep going please. You are much appreciated, thank you.
I love these riddles! Every riddle you posted was in the back of my head for the whole week and i even discussed it with people arround me. I love thinking about this. You really inspire me. And yes, the tears are real! Thank you Professor!
Noone can make you love simple harmonic motion more than this amazing professor. Regular physics teachers teach formulas and how to apply them. He does that, but he focuses on another thing, much more important indeed, which is how to love and admire the beauty of physics.
Great smile at the end of this video. Your passion for physics burns bright in your soul...it shows and it is inspiring to all of us. Gravity, quite literally, rocks!
ok, yes, but if you looked at what I did, before i googled the answer, i think you would have to agree that it was accomplished without benefit of fore-knowledge. i did not arrive at the ultimate answer but came within an order of magnitude using what i thought was a reasonable estimate and i did arrive at the idea that the transit time was independent of the longitude, latitude obfuscation that you threw at us. moreover, as good as your answer is, it did not reveal that the transit time is ONLY dependent on the density. that was derived on the wiki page. any planet, any size, if it has the same density as Earth's then ALL such tunnels will ALL have the same 42 minute transit time. that is simply amazing.
Here is a new problem idea you could present. Like the tunnel problem, the answer is astoundingly simple! (I didn't just analyse this, I actually measured this on a real ride!) A A roller coaster is traveling along a level track, and encounters a vertical loop in the track. What are the "G-forces" encountered by the riders as they go around the circle. How do these relate to the radius of the loop and the initial speed of entry? (Assume frictionless coaster, with the rider coincident with the CG of the car, and negligible moment-of-inertia of the car and rider. B How is the problem changed if the coaster is set up on another planet where the local "g" is different? C As the "G's" are rather high in parts of the loop, discuss various strategies for reducing the "G-loading" by changing track shape, but retaining the inverting loop. D How answers for parts A and B changed by the modifications in part C?
Walter Lewis and Richard Feynman you both are my inspiration for physics.Please keep helping us as much as you can.I'm Brazil and I need to say that I give up of everything and I'm giving all of me for the physics and that was one of the best decision that I have made.You Walter Lewin is part of this,thank you someday I want to be half of you are.I love to see the love that you have in your eyes because I have the same felling.Would you give me some tip for someone that is starting now? Thank you again.
sir ur lectures are awesome. i m in 11th grade but till now i hadnt seen such derivations of formulae. may god give u a very long life so to teach us and live with gud health and prosperity:)
I will not waste the opportunity to learn. One gains nothing by just looking up answer on the web without first making real efforts to understand and solve the problem (and there is no joy without trying).
Thank you for your great videos! :) How about some more experimental problems (like the vortex)? The motivation to try it out (and not just copy the solution from the web) could be higher for some people. But i also like your questions with some maths.
I just remembered the answer for a problem about orbits. I didn't look it up on the web. Besides, how does one write a math equation on here anyway? I don't know how to do that. So I gave the answer that I remembered. best as I could
Using google as a teacher is a very real problem. As someone that was there at the very beginning of the internet, working to make it better, I can say that we all thought the potential for improving education was very real, and very significant. The idea that one day the sum of the entire world's knowledge would be at the very fingertips of any researcher or student was incredibly attractive. I don't think anyone saw what this would do to the learning process. At least not to the degree that it apparently has had. The internet takes away the necessity of actually working out any problem yourself. One just has to search for the results of some others efforts and presto - they now have the answer. This completely diminishes the benefit of actually doing the work. It is a self-defeating process. Using the internet for research as it is being used today is robbing students of the real benefits of their educational endeavors. They really don't learn anything. I think the results wrought upon today's society speak for themselves.
just a question, the pendulum formula- I thought it was only derived for small angles of theta , hence I thought we could not use it here. Or am I totally off track?
And the interesting part is in pendulum case we have to approximate for small angles. In tunnels all of them have exactly same period. So pendulums are still harder. :D
I have the opposite problem of searching for an answer with brute force. I can never rest until I completely understand the solution, from different viewpoints even.
Dear professor, best regards and all the best from the deepest part of my heart. I would love if you can make a short video, explaining the phenomenon of why shadows have mass, or do they not?? P.S: Im not in the US so i had to ask a friend to get me Your amazing book, and it is Amazing! Thankyou
Professor, in your opinion, for me as a student of civil and industrial engineering, is Energy(power) engineering a better step as a second educational degree, or the field of Mechanics (as in Structural Analysis, Mechanics of Materials, Statics, etc.) is more fascinating? I really like Mechanics but as for a career, both are amazing. I know i am in charge of my decision, but your opinion might shed light on some things i might have not taken into consideration. Thanks for the first reply❤️
Sir, about the first solution... isn't there a gravitational force on my ship from the rest of the earth? I mean, the "orange peel" outside the little "r". If so, it's a geometrical nightmare to calculate the net force... Thanks.
Perhaps I'm mistaken, but I seem to remember you saying (in one of the lottery problems, I think) that you wanted only the numerical result, so that everyone would have to work out the result. Now you're saying that you want us to post the derivation.
it is a dream world Sir(in a certain sense), for the most part........perhaps a VR designed & renderd by Mind(BIG M) itself, for minds.......that sure seems to connect the most dots by far......& even if not........I don;t see how one's dreams are any less significant than any "real" daily routine......no matter how wild or mundane either...... I(& a growing # of others) think Consciousness as thE fundamental something rather than nothing as a "natural" digital information system/field/thingy is a paradigm to replace objective causality/materialism/determinism/reductionism etc....& may even be a solid kernel/shell for an actual TOE......as opposed to particles & forces which magically came out of nowhere & are expanding into nothing, that somehow formed brains as an "epi-phenomenon" ..... I'm NOT trying to convert this into a philosophy channel.......although my fairly recent propensity to favor such model(s) actually enhances my love of physics & is mathematical connection !
Sir Walter Lewin, my son Pratyush kumar had made a theory and a blueprint and he is also confident on it at 100%. He states that he is the only guy in the universe who can create 100% absolute vacuum on earth at the level we live. I.e. at lithosphere. So, what do you say? He is not getting a good platform to reveal his theory. Can you please help him . ?
Lectures by Walter Lewin. They will make you ♥ Physics. Yes, but till now it does not exist! Can you tell any platform where he should get others know about it.
A perfect vacuum is defined as a state with no matter particles, and also no photons. ... A perfect vacuum would be empty space with no atoms or any particles in it. *But there is no such thing because virtual particles are always popping in and out of existence*. Apart from that, no photons in an area of space means that all walls of that space must be at ZERO Kelvin. Any temperature higher than 0 K will produce blackbody radiation.
Wow i thougt about it so long i came of this. Amezing that it ryl worked but it made prefektly sense somehow if you look just at the Path of the object comperte to this on the object on an Pendel its not exactly like the path of an Pendel if you compere tha angels of the Tunnel with the angels of the Pendel put it does not matter becous it allways speeds Up constant if you get an larger Distanz Like straigt true the earth you would get an Bigger speed becous the distanz is Larger if you have just 1 m distnaz on the surface you have a Very very small distanz and the speed will be nearly 0 just amezing its the same effekt like on an Pendel! :D
Dear Professor Lewin, I am responding to your comments about people posting answers they have taken from the internet. I feel your disappointment and how it challenges your will to keep going, please don't be deterred by such action. I welcome your challenges and work on them assiduously - I got the main structure of the tunnel answer correct but fell down on the mathematics and recognition of correct application of formulae. I don't post as I am aware of my limitations - mainly my being unable to deliver a credible answer - but I do then go back into your lectures to work on the gaps the problem has highlighted. So, in short, there are probably many like me who are (until now, in my case) invisible to you but who are diligently using your problems and lectures to improve their knowledge; keep going please. You are much appreciated, thank you.
:)
I love these riddles! Every riddle you posted was in the back of my head for the whole week and i even discussed it with people arround me. I love thinking about this. You really inspire me. And yes, the tears are real!
Thank you Professor!
:)
Noone can make you love simple harmonic motion more than this amazing professor. Regular physics teachers teach formulas and how to apply them. He does that, but he focuses on another thing, much more important indeed, which is how to love and admire the beauty of physics.
Great smile at the end of this video. Your passion for physics burns bright in your soul...it shows and it is inspiring to all of us. Gravity, quite literally, rocks!
since i bought your book i began to really love physics and how it connects everything in the world, thank you walter lewin and keep it up!
super
I only discovered you were doing UA-cam just today. So awesome! I've watched your videos since 2010!
great!
ok, yes, but if you looked at what I did, before i googled the answer, i think you would have to agree that it was accomplished without benefit of fore-knowledge. i did not arrive at the ultimate answer but came within an order of magnitude using what i thought was a reasonable estimate and i did arrive at the idea that the transit time was independent of the longitude, latitude obfuscation that you threw at us.
moreover, as good as your answer is, it did not reveal that the transit time is ONLY dependent on the density. that was derived on the wiki page. any planet, any size, if it has the same density as Earth's then ALL such tunnels will ALL have the same 42 minute transit time. that is simply amazing.
Just discovered your videos. Really stunning. Georges from Paris France 💚
:)
Here is a new problem idea you could present. Like the tunnel problem, the answer is astoundingly simple! (I didn't just analyse this, I actually measured this on a real ride!)
A
A roller coaster is traveling along a level track, and encounters a vertical loop in the track. What are the "G-forces" encountered by the riders as they go around the circle. How do these relate to the radius of the loop and the initial speed of entry? (Assume frictionless coaster, with the rider coincident with the CG of the car, and negligible moment-of-inertia of the car and rider.
B
How is the problem changed if the coaster is set up on another planet where the local "g" is different?
C
As the "G's" are rather high in parts of the loop, discuss various strategies for reducing the "G-loading" by changing track shape, but retaining the inverting loop.
D
How answers for parts A and B changed by the modifications in part C?
:)
I've tears in my eyes too! Thanks!!!!!!
:)
I love you, professor !! You inspire me :D
:)
Incredible! Amazing! Hard to believe... it's not very intuitive. I agree this is ... really beautiful and fascinating!
:)
Walter Lewis and Richard Feynman you both are my inspiration for physics.Please keep helping us as much as you can.I'm Brazil and I need to say that I give up of everything and I'm giving all of me for the physics and that was one of the best decision that I have made.You Walter Lewin is part of this,thank you someday I want to be half of you are.I love to see the love that you have in your eyes because I have the same felling.Would you give me some tip for someone that is starting now? Thank you again.
You ❤️ Physics and that will enrich your life. No tips are needed.
Godspeed Professor 🙋🏻♂️
I haven't seen the problem but I love seeing you here Professor! I've been watching your MIT lectures on electromagnetism! :)
:)
Sir, I want to thank you for the immense help that you and your lectures have given to me.
I am really grateful for your work. Huge thanks.
:)
sir ur lectures are awesome. i m in 11th grade but till now i hadnt seen such derivations of formulae. may god give u a very long life so to teach us and live with gud health and prosperity:)
:)
Your way of looking at physics is very beautiful sir.
:)
I will not waste the opportunity to learn. One gains nothing by just looking up answer on the web without first making real efforts to understand and solve the problem (and there is no joy without trying).
:)
Thank you for your great videos! :)
How about some more experimental problems (like the vortex)? The motivation to try it out (and not just copy the solution from the web) could be higher for some people. But i also like your questions with some maths.
superb prof. really you make lovr physics
:)
I just remembered the answer for a problem about orbits. I didn't look it up on the web. Besides, how does one write a math equation on here anyway? I don't know how to do that. So I gave the answer that I remembered. best as I could
That is beautiful. But since the satellite is an oscillator that vibrates on two axis, and it is also a pendulum with L=r, that does make sense.
:)
Using google as a teacher is a very real problem. As someone that was there at the very beginning of the internet, working to make it better, I can say that we all thought the potential for improving education was very real, and very significant. The idea that one day the sum of the entire world's knowledge would be at the very fingertips of any researcher or student was incredibly attractive.
I don't think anyone saw what this would do to the learning process. At least not to the degree that it apparently has had.
The internet takes away the necessity of actually working out any problem yourself. One just has to search for the results of some others efforts and presto - they now have the answer. This completely diminishes the benefit of actually doing the work. It is a self-defeating process.
Using the internet for research as it is being used today is robbing students of the real benefits of their educational endeavors. They really don't learn anything. I think the results wrought upon today's society speak for themselves.
thanks for your thoughts
eagerly waiting for another physics problem,sir
one more week
just a question, the pendulum formula- I thought it was only derived for small angles of theta , hence I thought we could not use it here. Or am I totally off track?
correct small angles
And the interesting part is in pendulum case we have to approximate for small angles. In tunnels all of them have exactly same period. So pendulums are still harder. :D
yes
I have the opposite problem of searching for an answer with brute force. I can never rest until I completely understand the solution, from different viewpoints even.
:)
wonderful , sir.
:)
Dear professor, best regards and all the best from the deepest part of my heart.
I would love if you can make a short video, explaining the phenomenon of why shadows have mass, or do they not??
P.S: Im not in the US so i had to ask a friend to get me Your amazing book, and it is Amazing! Thankyou
shadows have no mass
Professor, in your opinion, for me as a student of civil and industrial engineering, is Energy(power) engineering a better step as a second educational degree, or the field of Mechanics (as in Structural Analysis, Mechanics of Materials, Statics, etc.) is more fascinating? I really like Mechanics but as for a career, both are amazing. I know i am in charge of my decision, but your opinion might shed light on some things i might have not taken into consideration. Thanks for the first reply❤️
do what fascinates you the most
If i can go back with time, i would have done pure Physics (too bad i cant fly with the speed of light 😋)
Sir, about the first solution... isn't there a gravitational force on my ship from the rest of the earth? I mean, the "orange peel" outside the little "r". If so, it's a geometrical nightmare to calculate the net force... Thanks.
question unclear
Perhaps I'm mistaken, but I seem to remember you saying (in one of the lottery problems, I think) that you wanted only the numerical result, so that everyone would have to work out the result. Now you're saying that you want us to post the derivation.
reasoning is a must here. It takes 20 sec to find the correct answer on the web.
What don't we get teachers like you now days? :(
:)
it is a dream world Sir(in a certain sense), for the most part........perhaps a VR designed & renderd by Mind(BIG M) itself, for minds.......that sure seems to connect the most dots by far......& even if not........I don;t see how one's dreams are any less significant than any "real" daily routine......no matter how wild or mundane either...... I(& a growing # of others) think Consciousness as thE fundamental something rather than nothing as a "natural" digital information system/field/thingy is a paradigm to replace objective causality/materialism/determinism/reductionism etc....& may even be a solid kernel/shell for an actual TOE......as opposed to particles & forces which magically came out of nowhere & are expanding into nothing, that somehow formed brains as an "epi-phenomenon" ..... I'm NOT trying to convert this into a philosophy channel.......although my fairly recent propensity to favor such model(s) actually enhances my love of physics & is mathematical connection !
wow this is exactly what I had
sir, can you please give me some suggestions on mathematical physics textbooks.
I am sorry but I can't.
I suggest you use the web.
sir u r frm which country:)
I guess my solution was correct then :)
the tear is real
:)
FIRST!!!
Sir Walter Lewin, my son Pratyush kumar had made a theory and a blueprint and he is also confident on it at 100%.
He states that he is the only guy in the universe who can create 100% absolute vacuum on earth at the level we live. I.e. at lithosphere. So, what do you say? He is not getting a good platform to reveal his theory. Can you please help him . ?
I cannot help him
absolute vacuum does not exist becoz of QM.
use google and quora
Lectures by Walter Lewin. They will make you ♥ Physics. Yes, but till now it does not exist! Can you tell any platform where he should get others know about it.
A perfect vacuum is defined as a state with no matter particles, and also no photons. ... A perfect vacuum would be empty space with no atoms or any particles in it. *But there is no such thing because virtual particles are always popping in and out of existence*.
Apart from that, no photons in an area of space means that all walls of that space must be at ZERO Kelvin. Any temperature higher than 0 K will produce blackbody radiation.
Wow i thougt about it so long i came of this. Amezing that it ryl worked but it made prefektly sense somehow if you look just at the Path of the object comperte to this on the object on an Pendel its not exactly like the path of an Pendel if you compere tha angels of the Tunnel with the angels of the Pendel put it does not matter becous it allways speeds Up constant if you get an larger Distanz Like straigt true the earth you would get an Bigger speed becous the distanz is Larger if you have just 1 m distnaz on the surface you have a Very very small distanz and the speed will be nearly 0 just amezing its the same effekt like on an Pendel! :D