I love this guy! I would enroll in whichever college he is teaching at just to attend his lectures. Physics is not my thing, but he makes it so interesting I want to learn everything this man has to teach!
whmozart I was 43 years at MIT; I retired in 2009. I gave 2 lectures at MIT and 16 lectures in Japan and India (2012 and 2014) after my retirement. My "farewell lecture" at MIT (May 16, 2011) has is my mot popular lecture. It has been viewed 4.5 million times. th-cam.com/video/sJG-rXBbmCc/w-d-xo.html
I am doing Electrical Engineering, and I came here accidentally, but ended up watching one lecture after an other without getting bored.. Walter Lewin is a great teacher, and i'll buy his book some day.
This is the way how physics (or any subject like that) should be taught... Love from India sir... Hope so every schools or institutes professor (or sir) starts explaining the things this way..
Prof. Lewis’s infectious enthusiasm inspired me almost 2 decades ago to study physics after I finished my basic medical degree. I have only joy and satisfaction for doing so, no regrets. I’ve gone on to make some fundamental discoveries of my own in the theory of wave interference. Thankyou so much sir! Wish I had the chance to meet you in real life.
@@lecturesbywalterlewin.they9259 Thankyou sir for your reply. It’s such an honor! In case you are interested, the name of my paper is “multiple slit interference: a hyperbola based analysis” which can easily be found and downloaded on a google search. I was very blessed to have had such a great teacher as you. You are a rare gemstone.
Watched this in 2016, 2017 and now 2018. Each time i watch it, I learn something new and enjoy the beauty of physics. Thank you sir :) I think I have an emotional resonance for you haha.
Astonishing didactic quality, at the very highest level, very possibly unique! And this is no vulgarization: the reasoning is as rigorous as it needs to be, and the equations are introduced as the obvious language of Physics, not as a hindrance to be suffered. I think all Professor Lewin's students get to feel the esthetic emotion of practicing Physics and the joy of understanding the physical world. Superb teacher, in the highest sense of the word!
You are one of the most indispensable gem for the whole world. I admire you the most sir, your lecture and practical experiments simultaneously let us understand even the most toughest topic in an esy way. Hats off to you sir.
Professor I want to thank you for wonderful work and your upbeat spirit. I am lying here in a Covid-19 ward feeling rather down. Your infectious love of physics is the only disease I want to have and maintain. Thank you for your words helping me now.
Maybe passion can’t be taught, but you can certainly teach with passion, thank you for sharing top quality content for free to everyone, you never know who can get inspired.
I could feel your passion to make others knowledgeable, sharing your life experiences in the subject that you love so much. Hats off to such Guru's. You made the session so interesting with those live demonstrations.
As a an amateur violinist I found this really interesting. A violin teacher I had a few years didn't understand why I tuned to 440hz on the basis that orchestral stringed instruments resonate better at 442hz. I still tune my violin to 440hz to this day.
Great sir, This is your love with physics that makes you different from many others . I loved the way you teach and really i do wish if every institution give practicals more importance than the theory.. Salute you sir.. May you live long and healthy life and keep teaching us this way.. Thank you With regards, Piyush Awasthi, INDIA
Hello professor!😊❤️ Now a days I'm reading your book 'for the love of physics'... It's very motivation and also informative. It gives & develop different approach of thinking... ❤️❤️
Sir you are amazing.........full concept..... Your lecture is like a Hollywood movie....... It gives the same pleasure to me when I watch a Hollywood movie......... Love from India..... Genius
The last moment when he changes his voice was really amazing.You are the GOD of physics.I am in love with physics.May you live long,so that I can get an opportunity to meet you.🙏🙏🙏🙏🙏💕💕💝💝.LOTS OF LOVE FROM ONAM.
19:20 - you cannot hear these organ pipes with such a low frequency, but you can feel it with your body. If you have ever visited the real organ concert (not listen by TV or headphobes) then you will feel your body vibration at low sounds frequencies. This brings you to the fantastic feeling of the live organ music.
What a great lecture and demonstration sit may Gid give u a long life u are the ver very great teacher of physics i learn many thing from u i salute u sir may God give along long life
I was reading the 1st chapter of "For the love of physics" and Walter said about how physics explains why and how many things are and do....and "why a flute makes sound" was on there......I'm gonna watch every bit of everything Professor Lewin.
All I can say is you are the best professor that i had ever seen. I loved all your lectures and the most remarkable one will be your last lectures with pendulum experiment along with the scattering of lights , that was really awesome. You made me to be more in love in Physics as I have always been. Thank you !!!!!!
Lectures by Walter Lewin. They will make you ♥ Physics. th-cam.com/channels/iEHVhv0SBMpP75JbzJShqw.html 300+ videos. Many of them with high resolution. This channel has all my lectures and talks.
Your luck will hold! At present (March 2016) my videos are being watched by more than half a million viewers each month. That's more than 6 million in a year!.
By the way, I believe finding a precise 440 hz A on the guitar was difficult because it is an equal temperament tuned instrument, rather than a just tuned instrument. As I expect you are aware, equal temperament is a system of tuning in which every pair of adjacent pitches is separated by the same interval, i.e., dividing the 12 chromatic notes into equal parts. This is close, but doesn’t quite match up with the natural harmonics, though it does allow the instrument to be played in all 12 keys. Tuning instruments to harmonic ratios is referred to as “just tuning”. Instruments tuned this way sound very good to the human ear, but only in the key that they are tuned. A violinist can adjust the finger position on any note to get to the best harmonics; a guitarist, who is bound by the position of the frets, cannot. Anyway, I think this might make an interesting side note in your next lecture on the subject.
Music does not need symmetric math. Noncommutative phase is the empirical truth of music, as Alain Connes points out. so if C is 1, octave 2 then G is 3 as overtone while F is 3 as undertone. So G=3=F at same time as noncommutative phase. Sir James Jeans points out that the infinite spiral of fifths is the empirical truth of music - this is because of noncommutative phase as quantum nonlocality - a geometric dimension of zero. So symmetric math does not capture the secret of music as human hearing is faster than Fourier Uncertainty. Nonwestern music knows the secret of music as infinite time-frequency resonance energy. de Broglie's Law of Phase Harmony also rediscovered this secret of music.
THIS IS PERFECT!!!!!!!!! I am trying to describe harmonics and timbre to a friend who is helping me make the tools I need to make trumpets from scratch, and I showed him this lecture and he got it!! what an awesome lecture and what an awesome professor!!!! - a trumpet player
THANK YOU SO MUCH Dr. LEWIN! I was wondering if you have an email address or some other means of contacting you. I have some questions on harmonics, progression, timbre, and so on for a project I am working on that I cannot seem to find definitive answers for, and it would be an extreme honour to have your take/opinion on it! thank you so much again!!! Ezra
please professor walter lewin, i have already attended your lectures from 8.01 and 8.02, i think the best classes i have ever seen in my life. I am Brazilian and do not understand English perfectly, and the 8.03 classes are not translated. I ask that if possible, you provide translations for 8.03. Thank you.
was reading the wonders of resonance chap harmonies of strings and winds in YOUR BOOK SIR AND GUESS WHAT TH-cam RECOMMENDED ME THIS GEM LECTURE I DIDNT HAVE A BETTER FEEL OF HARMONICS AND RESONANCE EVER !!!!!!!!!
Dr. Lewin , Thank youuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuYou are amazing You Wouldn't believe How much your lectures affected my passion to science Students at MIT are so lucky to have you there. I was always hoping having brilliant teacher at this unbelievable level of knowledge. MIT thank you for sharing this video , keep on
You are just amazing sir. I am a PhD student in Physics and the way you teach is giving me a bright view of the nature to love science and our elegant world. I remember once you said "You must love it or do not touch it"
Still remember why army is not allowed to March on pull so that resonance of army men March doesn't match with natural frequency of pull because if it does then pull will resonate up and down.. Love physics😍😍😍😍😍
I like because he bring the experiments that influent student to study. As he said the unique instrument, you may observe from the waveform, time to change frequency, resonance and etc.
I'm studying the relation that exists among physics/math and music, for instance: a major chord which is audibly consonant is composed by the first three odd harmonics, thats: 1, 3 and 5. If 1 is C, then 3 would be G and five would be E, so you would have a C major chord (C+E+G). On the other hand if the frecuencies are obtained by dividing the fundamental frequency in integer numbers (instead of multiplying it, as in the example above), that's: 1/1, 1/3, 1/5. In this case if 1/1 is G, 1/3 would be C and 1/5 would be E flat, that's a C minor chord (C+Eb+G) which is also consonant. The interesting thing is that while mathematically this chords are inverse (the Major and the Minor), musically each one of them evoques a certain mood or feeling which, although music is subjective, could be generalized as oposite. In the one hand, a Major chord evokes a harm, happy, light sound, while a Minor chord evoques a cold, sad, dark sound.
Why TH-cam isn't recommending that sort of video and always pops stupid music video this is real knowledge I get more information from this video as compared to my entire School life and College life Thank you Sir love you
Professor, it is really an enjoyable one hour to watch your lecture and your experiment. The last one experiment, I have to hold my breath! Thank you for the great lecture and make me love Physics!
I define 3 phenomena regarding self-excited vibrations: Natural Frequency, Critical Speed and Resonance. They are related but different. Natural Frequency is a physical property of any physical object dependent solely on the mass and rigidity of the object. Critical Speed is the turning speed of any rotating object that matches its natural frequency. Resonance is the extremely high amplitude response of an object that is being excited at its natural frequency or for a rotating shaft, at its criitical speed.
You are a great professor, I wish I took physics at that college! Osu could learn a thing or two from this video about teaching physics to inspire students to maybe do a minor in it instead of teaching it to weed students out. For a while I lost my interest in physics due to how my college teaches it but this makes me interested in it again, thank you.
It seems that Walter Lewin is like the official unofficial mascot for the Dept. of Physics at MIT. Love this guy.
:)
I just clcked here randomly and ended up watching the whole thing. Fascinating! looking for more now!
There is plenty "more"
I love this guy! I would enroll in whichever college he is teaching at just to attend his lectures. Physics is not my thing, but he makes it so interesting I want to learn everything this man has to teach!
whmozart I was 43 years at MIT; I retired in 2009. I gave 2 lectures at MIT and 16 lectures in Japan and India (2012 and 2014) after my retirement. My "farewell lecture" at MIT (May 16, 2011) has is my mot popular lecture. It has been viewed 4.5 million times. th-cam.com/video/sJG-rXBbmCc/w-d-xo.html
wait a second... are you THE Walter Lewin responding here??
Yes I am the REAL Walter Lewin and I run this channel. The woman who is playing the violin (see thumb nail) is my daughter Pauline.
I am doing Electrical Engineering, and I came here accidentally, but ended up watching one lecture after an other without getting bored.. Walter Lewin is a great teacher, and i'll buy his book some day.
Did u become an engineer now?
when your passion is your profession...
That kind of dedication shows up...
I had also gave 10 minutes standing ovation in my room after seeing this lecture
:)
Sir,truely this video made me fall in love with sound!
It is a amazing lecture wish I can hear it 40 years ago , thank you Prof Lewin
This is the way how physics (or any subject like that) should be taught... Love from India sir... Hope so every schools or institutes professor (or sir) starts explaining the things this way..
i can't stop watching your videos sir your style of teaching is wonderful
The great thing about reading your book would be hearing the lines narrated by you inside .
A great legend !
Prof. Lewis’s infectious enthusiasm inspired me almost 2 decades ago to study physics after I finished my basic medical degree. I have only joy and satisfaction for doing so, no regrets. I’ve gone on to make some fundamental discoveries of my own in the theory of wave interference. Thankyou so much sir! Wish I had the chance to meet you in real life.
you are most welcome!
@@lecturesbywalterlewin.they9259 Thankyou sir for your reply. It’s such an honor! In case you are interested, the name of my paper is “multiple slit interference: a hyperbola based analysis” which can easily be found and downloaded on a google search.
I was very blessed to have had such a great teacher as you. You are a rare gemstone.
The best est professor ever...........really for the love of physics!!!!!! great.........
+Shweta Chauhan Thank you!
I am glad they record everything. Teachers like him are legends. In my whole life, I only met 2 people like him. Deep respect.
thank you for your kind words
James Moriarty of Sixty Simbols is another great one.
The one and only .Teaching dedication at its best.
Watched this in 2016, 2017 and now 2018. Each time i watch it, I learn something new and enjoy the beauty of physics. Thank you sir :) I think I have an emotional resonance for you haha.
Great lecture. Thanks to your lectures I fell in love with Physics. Greetings from Russia
you always have something new to surprise us. thank you, sir, for your great service
A lecture which will be heard for ages ! Love for Physics and Love for Walter Lewin !
I have been looking at your videos since 4 to 5 years, Walter Lewin is simply great lecturer
music...pure sensation. nothing quite like it. love
I can watch your lessons for many hours, very detailed, these explanations are wonderful,thank you very much for content you provide,professor.
Astonishing didactic quality, at the very highest level, very possibly unique!
And this is no vulgarization: the reasoning is as rigorous as it needs to be, and the equations are introduced as the obvious language of Physics, not as a hindrance to be suffered.
I think all Professor Lewin's students get to feel the esthetic emotion of practicing Physics and the joy of understanding the physical world.
Superb teacher, in the highest sense of the word!
Could not help stop myself watching the whole lecture ! Great as always.
You are one of the most indispensable gem for the whole world. I admire you the most sir, your lecture and practical experiments simultaneously let us understand even the most toughest topic in an esy way.
Hats off to you sir.
Walter sir is mother of all wisdom❤
Professor I want to thank you for wonderful work and your upbeat spirit. I am lying here in a Covid-19 ward feeling rather down. Your infectious love of physics is the only disease I want to have and maintain. Thank you for your words helping me now.
Maybe passion can’t be taught, but you can certainly teach with passion, thank you for sharing top quality content for free to everyone, you never know who can get inspired.
I have only watched some of his lectures so far. Now I am gonna watch them all...
I could feel your passion to make others knowledgeable, sharing your life experiences in the subject that you love so much. Hats off to such Guru's. You made the session so interesting with those live demonstrations.
I'm wondering how and/or why 21 people could have pressed dislike button for this wonderful lecture!! Love your lectures Walter Lewin :-)
Everyone clapping.... 1000 years later still clapping ;)
As a an amateur violinist I found this really interesting. A violin teacher I had a few years didn't understand why I tuned to 440hz on the basis that orchestral stringed instruments resonate better at 442hz. I still tune my violin to 440hz to this day.
Absolutely Amazing!!!
Dear,
You are the best of the best proffessor i ever seen...👍
What a lecture! Seeing videos of respected walter lewin sir i have made interest in physics so much.
This is very very helpful.
Fantastic!!!! Love it!!
I love his classes. he's a true Rabi.
:)
Great sir,
This is your love with physics that makes you different from many others . I loved the way you teach and really i do wish if every institution give practicals more importance than the theory..
Salute you sir..
May you live long and healthy life and keep teaching us this way..
Thank you
With regards,
Piyush Awasthi,
INDIA
thanks for your kind words
Lectures by Walter Lewin. They will make you ♥ Physics. Space
53:50
Gets you to the start of the wine glass break attempted
BUT WATCH THE ENTIRE VIDEO...TRULY AMAZINGLY EDUCATIONAL AND ENTERTAINING!
To do something for the love off it, is incredible. Legend
That little stunt at the end was pure commitment. Great guy and awsome lecture
Sir Walter! I am a musician, and thank you for that wonderful lecture! You made me love music and physics even more! 😁
Fascinating!
so is:
Harmonic overtone singing
Hello professor!😊❤️
Now a days I'm reading your book 'for the love of physics'...
It's very motivation and also informative. It gives & develop different approach of thinking...
❤️❤️
Best explanation ever seen. Inspired me to see all the videos . Thanks for educating us !!!
Sir I love this Lesson (Reasonance ).
Sir you are amazing.........full concept..... Your lecture is like a Hollywood movie....... It gives the same pleasure to me when I watch a Hollywood movie......... Love from India..... Genius
If all our mentors were as good we would be in a far better place than we are now - well done
The best professor for sure. Mr Walter, we need people like you, here in Italy. Unfortunly I haven't seen any of them here yet...
+Marco Keep looking!
I love the way you teach
You are my first and adorable Physic Teacher and forever will be🥰🥰🥰
how satisfying are these lectures..
definitely noble prize should be given to you for your way of teaching
The last moment when he changes his voice was really amazing.You are the GOD of physics.I am in love with physics.May you live long,so that I can get an opportunity to meet you.🙏🙏🙏🙏🙏💕💕💝💝.LOTS OF LOVE FROM ONAM.
19:20 - you cannot hear these organ pipes with such a low frequency, but you can feel it with your body. If you have ever visited the real organ concert (not listen by TV or headphobes) then you will feel your body vibration at low sounds frequencies. This brings you to the fantastic feeling of the live organ music.
Sir you are so creative in teaching a wonderfully subject in the world God bless you and you are my role model.
I love this man!
Thank you sir.
You explanation is realistic.
Love from India,West Bengal,Bankura.
Sir, you may not aware how your videos helping millions of student, really you are God of physics.
23:00 It's amazing that I can feel the frequency difference just by turning the pipe!
what a wonderful man
Sir, You are a great Teacher .
I watched complete. ❤
What a great lecture and demonstration sit may Gid give u a long life u are the ver very great teacher of physics i learn many thing from u i salute u sir may God give along long life
I was reading the 1st chapter of "For the love of physics" and Walter said about how physics explains why and how many things are and do....and "why a flute makes sound" was on there......I'm gonna watch every bit of everything Professor Lewin.
All I can say is you are the best professor that i had ever seen. I loved all your lectures and the most remarkable one will be your last lectures with pendulum experiment along with the scattering of lights , that was really awesome. You made me to be more in love in Physics as I have always been. Thank you !!!!!!
:)
The earth never seen such a talented person ever.... May Allah easy ur life after world life
Thanks Rould for your kind words.
What a fantastic teacher!!!!!!
Lectures by Walter Lewin. They will make you ♥ Physics.
th-cam.com/channels/iEHVhv0SBMpP75JbzJShqw.html
300+ videos. Many of them with high resolution. This channel has all my lectures and talks.
Marvelous. Bless you for making these videos available to the world. If our luck holds, they will be here for many generations to come.
Your luck will hold! At present (March 2016) my videos are being watched by more than half a million viewers each month. That's more than 6 million in a year!.
By the way, I believe finding a precise 440 hz A on the guitar was difficult because it is an equal temperament tuned instrument, rather than a just tuned instrument. As I expect you are aware, equal temperament is a system of tuning in which every pair of adjacent pitches is separated by the same interval, i.e., dividing the 12 chromatic notes into equal parts. This is close, but doesn’t quite match up with the natural harmonics, though it does allow the instrument to be played in all 12 keys. Tuning instruments to harmonic ratios is referred to as “just tuning”. Instruments tuned this way sound very good to the human ear, but only in the key that they are tuned. A violinist can adjust the finger position on any note to get to the best harmonics; a guitarist, who is bound by the position of the frets, cannot. Anyway, I think this might make an interesting side note in your next lecture on the subject.
There is no greater higher calling than a teacher. Thank you Prof. Lewin... :--)
Music does not need symmetric math. Noncommutative phase is the empirical truth of music, as Alain Connes points out. so if C is 1, octave 2 then G is 3 as overtone while F is 3 as undertone. So G=3=F at same time as noncommutative phase. Sir James Jeans points out that the infinite spiral of fifths is the empirical truth of music - this is because of noncommutative phase as quantum nonlocality - a geometric dimension of zero. So symmetric math does not capture the secret of music as human hearing is faster than Fourier Uncertainty. Nonwestern music knows the secret of music as infinite time-frequency resonance energy. de Broglie's Law of Phase Harmony also rediscovered this secret of music.
It's a fantastic lecturer. my respect to you sir. thanks lots.
You are most welcome
THIS IS PERFECT!!!!!!!!! I am trying to describe harmonics and timbre to a friend who is helping me make the tools I need to make trumpets from scratch, and I showed him this lecture and he got it!! what an awesome lecture and what an awesome professor!!!!
- a trumpet player
ha ha ha
THANK YOU SO MUCH Dr. LEWIN! I was wondering if you have an email address or some other means of contacting you. I have some questions on harmonics, progression, timbre, and so on for a project I am working on that I cannot seem to find definitive answers for, and it would be an extreme honour to have your take/opinion on it!
thank you so much again!!!
Ezra
Sir today is 5th Sep, a special day for appreciation of Teachers and for me you are the worlds🌎 best Teacher.
With 💘
Happy Teachers Day.
Sheer excellence can never be out done!
Divine knowledge god bless sir
7:22 Watch the guy with glasses and a blue shirt😂 Im right there with you
please professor walter lewin, i have already attended your lectures from 8.01 and 8.02, i think the best classes i have ever seen in my life. I am Brazilian and do not understand English perfectly, and the 8.03 classes are not translated. I ask that if possible, you provide translations for 8.03. Thank you.
was reading the wonders of resonance chap harmonies of strings and winds in YOUR BOOK SIR
AND GUESS WHAT TH-cam RECOMMENDED ME THIS GEM LECTURE
I DIDNT HAVE A BETTER FEEL OF HARMONICS AND RESONANCE EVER !!!!!!!!!
Wonderful!
I'm getting your biggest fan day by day❤️
MR. lewiN u R oldddd
but the purest GOLD
+Saad Siddiqui Thank you kindly - happy 2016
Dr. Lewin , Thank youuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuYou are amazing You Wouldn't believe How much your lectures affected my passion to science Students at MIT are so lucky to have you there. I was always hoping having brilliant teacher at this unbelievable level of knowledge. MIT thank you for sharing this video , keep on
+abu mohannad Ettwadi Thanks Abu for your kind words.
Exact explanation I was looking for. Amazing.
Great to hear!
You are just amazing sir. I am a PhD student in Physics and the way you teach is giving me a bright view of the nature to love science and our elegant world. I remember once you said "You must love it or do not touch it"
Still remember why army is not allowed to March on pull so that resonance of army men March doesn't match with natural frequency of pull because if it does then pull will resonate up and down.. Love physics😍😍😍😍😍
I like because he bring the experiments that influent student to study. As he said the unique instrument, you may observe from the waveform, time to change frequency, resonance and etc.
What a really great professor! Thanks for this video!
:)
Was having such a hard time studying physics i wanted to give up
Your lectures reminded me why i wanted to study physics in the first place
I'm studying the relation that exists among physics/math and music, for instance: a major chord which is audibly consonant is composed by the first three odd harmonics, thats: 1, 3 and 5. If 1 is C, then 3 would be G and five would be E, so you would have a C major chord (C+E+G). On the other hand if the frecuencies are obtained by dividing the fundamental frequency in integer numbers (instead of multiplying it, as in the example above), that's: 1/1, 1/3, 1/5. In this case if 1/1 is G, 1/3 would be C and 1/5 would be E flat, that's a C minor chord (C+Eb+G) which is also consonant. The interesting thing is that while mathematically this chords are inverse (the Major and the Minor), musically each one of them evoques a certain mood or feeling which, although music is subjective, could be generalized as oposite. In the one hand, a Major chord evokes a harm, happy, light sound, while a Minor chord evoques a cold, sad, dark sound.
Why TH-cam isn't recommending that sort of video and always pops stupid music video this is real knowledge
I get more information from this video as compared to my entire School life and College life
Thank you Sir love you
This is the best ever physics lecture I have ever seen. Thank you soo much respected sir for enriching our minds.♥️ from India
this talk was for kids + their parents
Impressive job!!
Great lecture thank you sir 🙌
Sir ,
You are really great..
:)
It feels like nature incarnation ...sir lewin !
How is it possible for a professor to teach in this incredible way...I do not have the answer...It is just unbelievable!!!!!!!!!!!!
:)
Thank you Prof.
thank you for this
Professor, it is really an enjoyable one hour to watch your lecture and your experiment. The last one experiment, I have to hold my breath! Thank you for the great lecture and make me love Physics!
:)
I define 3 phenomena regarding self-excited vibrations: Natural Frequency, Critical Speed and Resonance. They are related but different. Natural Frequency is a physical property of any physical object dependent solely on the mass and rigidity of the object. Critical Speed is the turning speed of any rotating object that matches its natural frequency. Resonance is the extremely high amplitude response of an object that is being excited at its natural frequency or for a rotating shaft, at its criitical speed.
Awesome lecture. Beginner musicians.
sit Walter lewin . Just awesome 💙
You are a great professor, I wish I took physics at that college! Osu could learn a thing or two from this video about teaching physics to inspire students to maybe do a minor in it instead of teaching it to weed students out. For a while I lost my interest in physics due to how my college teaches it but this makes me interested in it again, thank you.
:)
Super sir , Explain is really good 😊
You inspire me 😍😍😍