8.01x - Lect 5 - Circular Motion, Centripetal Forces, Perceived Gravity 

I remember watching this lecture when I was in high school and was blown away at how cool physics could be. I’m now a second year PhD student in astrophysics, thanks Professor Lewin 🙏

I'm a 71-year-old semi-retired university psychology professor and I spend hours watching Dr. Lewin's lectures. Fascinating, absolutely fascinating.

Hi sir I'm 11th standard guy preparing for JEE mains & Advanced. So I'm watching you're lectures and these are very helpful . Thanks ❤

It's an honour to be able to watch these lectures. Thank you professor Lewin!

I would love to take physics with Professor Lewin! These are the best lectures.

0:00- uniform circular motion (+ex rotate disc) +Just introduce pull & push force (there is no such thing as a free lunch) + the motion after we cut the spring 12:40 - planet around the sun + diagram a - R + slope ~ 1/R^2 17:28 - basic ideal behind a centrifuge + experiment in order to dry the lettuce 22:25: the connection between centripetal acceleration and perceived gravity (such amazing) 32:00: explain about the experiment with a simple centrifuge 42:50: explain about the experiment with a bucket of water Thanks to Walter Lewin, you make me feel happy every single lecture

Never thought that I'd be able to attend mit lectures from home ! Thank you very much professor! You are the best

Walter Lewin is the best physics teacher there is! He truly preserves and motivates me even more for my love of physics, maths, and most of all the love of scientific pursuit!!!

Sir, one thing I think it's incredible is that you post your lectures on Internet. It sure helps a lot of people, not only because they're really easy to understand and very memorable, but also because they're free. Thank you a lot, Mr. Lewin

Dr. Lewin, Thank you so much for these amazing lectures. I have been out of academia for 4 years and my application for a PhD was recently accepted. I'm watching your videos to prepare for graduate studies and strengthen my foundations. I will remain forever in your debt!

I've been trying to find a decent class lecture on this for so long. Thank you, it's been very helpful.

I haven't been so engaged in the physics lecture as much as I have been watching this video. Absolutely fascinating!

I'm an undergraduate physics and math student taking some higher level courses right now and I really enjoy watching your videos because it really helps drive the concepts beyond just the mathematics. It also reminds me, when I'm frustrated, why I joined the major in the first place and not to give up. You are an incredible teacher and I thank you for sharing all of this knowledge with us.

And there goes my fear of circular motin and it's applications. Thank You !!

most inspiring teacher ever! thank you Mr.Lewin for still inspiring us.

1. Excellent demos. 2. Very thoroughly explained, whereby anyone can understand the concept!!!!

Words are inadequate to express my joy for your help.

Man I wish I've binge watch these lectures when I was learning this on college. Instead we just solve practice problems through memorizing these equations without getting a feel of what it really meant. Thank you for this lecture

His lectures have an awesome flow, love them.

Great teacher , whoever attend his lectures at the time was really lucky , worth every second of a life time

I never feel bored in your class sir. You are just awesome 😃

Thank you, Mr Lewin. I will remember this for life

I am from Assam, India aged almost 40 and now I have realised to the core of my heart that I have not learnt physics at all though I work as a government service engineer thanks to the education systems/scoring systems we have back here in India. I pledged to myself I will learn atleast all the fundamental concepts of physics before I die as it is so fascinating & so close to the nature around us- Measurements with understanding of degree of uncertainty 😊- Thank you prof. hopefully you and HC Verma sir would make my life's next few years a fascinating journey

Thank you! I love learning from the best! What a world we live in to have this opportunity!

We can't expect this dedication in India for some hundred years from now.....🙏

So FASCINATING😍. I love this guys lectures.

Centripetal acceleration is cool. Your explanations and demonstrations are even cooler. Thanks!

Nothing is as good as physics prof... thanks for making us understand everything so easily 🙏🏻

Always a great lecture. Cirurgical precision. And it’s not negotiable! Thank u for the masterpiece of of your entire career.

Your grandmother is really awesome...🙏

Respected Walter sir , I am proud of you that my physics teacher recommends you and he teaches us after seeing your lectures🙏🙏🙏🙏

Thanks for providing all these amazing experiments for free.

That's why as a pilot I experience the gravity towards my feet when I do a tight turn (coordinated of course). Great lecture!

Being a Physics faculty i had drawn a lot of inspiration from you professor.

i cant explain when i understand each and every thing with your experiments and with your teaching the satisfaction it gave me is just amazing i never understand physics so beautifully

This is a far better resource than oxford textbooks, no mistakes in these videos!

Ultimate physics teacher with real life (example)stunts in hand. We miss you sir! but we follow your lectures🤘

Great..excellent..all are very small word for you. You are unique, thank you sir.

Love your anima and lectures. Thank you proffessor!

I literaally have tears in my eyes Are these type of professors of physics belong to this world?No words just thank you so much professor

the basic idea behind centrifuge just blew my mind. It was like.... I mean..oh god! I can't express it!

19:00 This explains everything

In my mind you are the very kind father to me not just a teacher. Wish bests for you.

Sir you always have a unique way in your every lectures, I HAD JUST FALLEN IN LOVE WITH PHYSICS because of you. Thanks 😊

I knew this was old but it took a long time for it to hit me that this was before Pluto was demoted from a planet in 2006. Wow.

My teacher makes me watch these before every class because this guy actually knows what he is talking about.

I must say, what a wonderful lecture. While I may not have had the chance to attend MIT in the late '90s, these videos have provided me with an incredible opportunity to learn, almost as if I haven't missed out on anything at all. Walter, you're truly changing the world in a quantum realm, overcoming barriers that would typically determine who gets educational opportunities based on factors like geography, race, finances, and social status. In this quantum realm, it's akin to winning a lottery. Your work showcases that you're an eternal being capable of exerting control beyond our comprehension of space-time, and that's truly amazing. The simple explanation is that our works is just like that with each victory giving us the ability to reach further forward and further backward; that means this is nice and all but we need to pick up the pace if we ever want to complete our goals and enjoy the our life forward in eternity

Sir these lectures are fantastic as you get to learn the concepts in a better way, using real life examples and experimentations. Thank you for such an assistance.

Soooooo good. Thank you very much Professor🙏🏻

In India we are taught this in class 11 😂 btw great explanation ❤️❤️🔥

Professor Lewin is Best teacher on RU-vid ❤️❤️🔝🔝👌👍 love respect from india

Sir you are the epitome for love towards physics ❤️ I respect you.

19:00 absolutely genius!

Wow what a lecture ⚡😘 Whatta lecturer💫

Open chested Salute to you Sir 🙏 Lots of love and Thanks from India 🇮🇳❣️🇮🇳

Hi sir, I'm a student from Vietnam, your lecture is really fun and helpful for me, the way you explain and connect the physics to the real life makes me feel the world is brilliant and wonderful ever. Thank you ❤

How many lucky students are sitting. I wish our teachers were like this Our teachers only disappoint us and ruin our future.

Sir, you save the lives of physics students everyday! I want to simply thank you.

i am glad to watch lectures by one of the best physics professor in the world :) i love science! and your class is too interesting . thankyou!

This is just a fantastic series of lectures. Professor Lewin why couldnt you have taught me physics in school!

10:31 legend

I was so dumb , few months back my mentality for physics was not like today. Thanku so much sir Lewin ❤️😇

Thank you professor Lewin for such beautiful sessions.. Grateful to have his lectures free of cost. Thank you sir..

as usual amazing lectures by professor! at around the 10 min mark, when you are discussing about the trajectory of the ball when the string/pull is cut; the way i understand this is by imagining shot put players. they do a spinning motion but in the end the ball travels straight!

Everytime I am heartbroken i watch this lecture. I dont know why but thiss calms me. I have watched this 17times by now❤️

Very few teachers are able to make physics meaningful and interesting.. Thank you Sir❤️

just another example of why MIT is the greatest University in the world... Professor Lewin performs a dry run of each lecture twice to an empty classroom before he goes on "live". ever notice how he never needs to pause to collect his thoughts? That he never repeats himself? THE BEST ...

Grateful to have his lectures free of cost. Thank you sir.

Hi, and thank you.

19:00 superb

It takes me years to actually know this that physics can be fun. Credit goes to you legend ❤️ 🙏thank you sir

Never understood any physics this better. Thank you Dr. Lewin

Perfect explanations! Thank you from Israel..! (:

Professor, I am curious to know more about the gravity you mentioned at 45:00 Is that what some people mistakenly attribute "Centrifugal Force" to? Also, does the person being swung around experience such a (perceived) gravity because of Newton's Third Law of Equal and Opposite Reactions? As in, when there is a tension force pulling downwards on the person, the person experiences a force in the opposite direction? Thank you!

These are priceless lectures.

Best physics professor on RU-vid!!!!

2:13 Did anyone notice a fluctuation in 'T' Omega=2π/T This 'T' ???😱😱

very clear sir thank you very much but I want to ask you A question How can we study the relationship between centrepital acceleration and radius is it always linear?

Thank you professor Lewin for such beautiful sessions.

Love his elucidation... It's divine❤❤❤

Imagine having your sleeping quarters in the middle of a wheel :0

Professor, is there any scholarship exam that I can apply for to study at MIT?

Huge respect, sir. It’s a great coincidence that I studied these topics just some hours ago. And now I found this lecture while scrolling the timeline. This lecture is worthwhile. ❤

His lectures are simple ,he is simple yet they are the best.

Hello Prof. Lewin! Watching your physics videos have elevated my interest in physics. I have not taken high school physics and I have just basic knowledge of physics. I am wondering if I start now (I am in mid twenties), will I be comprehend physics in the real sense? I have been doing some research on this topic and many people have written that if you don't start from an early age, it is difficult to understand. What is your take? when it comes physics and its understanding, I think your advice matters the most to me.

Hi sir I’m a class 11 jee student too and I find these lectures really helpful as in coaching we mostly spend all our time on ways of solving problems and never get to appreciate the beauty being the topic and the subject. You classes really make me understand why thing happens and make me love physics which I turn helps me solve problems too! And I wanted to thank you for that . Also I wanted to know which text book you were using during the lecture

I'm fortunate to have access to your lectures SIR...IM NOT IN REGRET THOUGH IM 60 YEARS NOW....I ADMIRE AT YOU AND TRY TO LEARN AND UNDERSTAND WHICH MAKES ME HAPPY...ALSO NOW I UNDERSTAND HOW GREAT UNIVERSITIES GET THEIR STATUS.... 🙏🙏🙏🙏PLK

YOU ARE MY NEW HERO

"Lettuce fill this with water..." hehehehehehe

Is there any way I can become professor of physics at MIT. I mean what must be qualifications to get job of teacher at MIT.

Lectures are very amazing. Thank you sir for such an interesting lecture.

Very illustrative class indeed. The equivalence principle is implicitly assumed. I am a junior theoretical physicist now working on quantum fields in classical backgrounds (cosmological particle production) which strongly violates the strong equivalence principle. It is interesting to study the (in)equivalence of the different equivalence principles. Thank you professor for uploading these lectures, I wish mine were like this when I first took classical mechanics.

I'm really curious as to what happens when the video cuts.

i thought there was no thing as centrifugal force ...now you introduced that concept through perceived gravity ...now im confused???😲😲😕😵

It's really good...and the energy he has is unbelievable...u increases the curiosity of physics in our life

Thank you for your amazing lecture, sir. I have loved the experiment with the bucket.

Dr. Lewin, your lectures are just amazing. If you had to chose between IE Irodov and HC Verma, which one would you chose?

is there connection between physics and chemistry

I used to hate physics but after watching your lectures professor I have become the best at physics and now it’s my favorite❤️thank you for your hard work

Every time I think before seeing these 10th grade physics topics is that what can be new in this topic??... But at the end I'm always ended up being amazed 🤨 This man can never be boring. You are a true legendary professor..💯