8.01x - Lect 5 - Circular Motion, Centripetal Forces, Perceived Gravity
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- čas přidán 6. 02. 2015
- Circular Motion - Centrifuges Moving - Reference Frames - Perceived Gravity
Lecture Notes, Orbital Information on Planets: freepdfhosting.com/fa00f3a0d0.pdf
Assignments Lecture 5, 6, 7 and 8: freepdfhosting.com/95e6843397.pdf
Solutions Lecture 5, 6, 7 and 8: freepdfhosting.com/4984cbb7f1.pdf - Věda a technologie
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 🙏
want a cookie?
I want to be an astrophysicist. I’m taking honors physics right now in junior year of high school. I’m not ready yet, but I want to get better and one day become one.
@@shadeyfang8564 It is really cool of you. However, I want to be an astrophysicist too. I am just in 11th grade and try to emphasize my problem-solving and concept-clearing. Any suggestion can I get?
I'm in 10 th grade and want to study astrophysics... don't know wether my dream could ever come true or not
These lectures are very interesting as well informative...I like to watch them ...
I'm a 71-year-old semi-retired university psychology professor and I spend hours watching Dr. Lewin's lectures. Fascinating, absolutely fascinating.
So why you want to learn physics
@@ManojKumar-cj7oj he's not even eligible for jee now
MANOJ KUMAR professors of different disciplines love to watch each other teach. I am an artist and I love watching tutorials on maths, physics, and other science.
Hey!! It's all about passion age doesn't matter and you don't learn physics only for JEE it has more dept then that.'
@@toukatouka5768 vinayak no one here is for jee and nor do americans know what jee is in fact people are here for ap for some good college like MIT
It's an honour to be able to watch these lectures.
Thank you professor Lewin!
:)
@@lecturesbywalterlewin.they9259 😊
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
You made the day easy.
Thanks
Tysm ❤️
Thank you 😊
I would love to take physics with Professor Lewin! These are the best lectures.
+CZcamsExplorer :) :) :)
I'm only 16:26 into the lecture, so apologies if it's answered later, or if I missed it.. but isn't the "one over R squared law" missing a whole bunch of factors? Like the gravitational pull from nearby masses OTHER than the sun?
Good teacher
Dalton Landis That is why a was proportional to 1 / R^2, and not equal. There is a proportionality sign, not the equal sign. If you add the extra factors it becomes equal.
Well I guess you are in a sense
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 ❤
All the best
@@lecturesbywalterlewin.they9259 Thanks!
2025 aispirant
way to IIT is much difficult
@@makeitwithyashbcz he is goat 🐐
Never thought that I'd be able to attend mit lectures from home !
Thank you very much professor!
You are the best
Most welcome!
@@lecturesbywalterlewin.they9259THE UNDERSTANDING OF WHAT ARE GALACTIC JETS AND THE SOLUTION TO WHAT IS THE CORONAL HEATING “PROBLEM”:
Consider what is E=MC2. The stars AND PLANETS are POINTS in the night sky ON BALANCE. Two AND three dimensional SPACE are BALANCED. Great. (Indeed, consider TIME AND time dilation ON BALANCE.) This CLEARLY solves what is the coronal heating “problem”. REGARDING WHAT IS E=MC2, c squared CLEARLY AND NECESSARILY represents a dimension of SPACE (ON BALANCE). Great. I have CLEARLY proven what is the FOURTH DIMENSION. ELECTROMAGNETISM/energy is gravity.
What is E=MC2 is the reason why what are OBJECTS may fall at the SAME RATE. Great !!!!
By Frank Martin DiMeglio
Consider what is THE EYE ON BALANCE. Notice what is the BLUE sky. ELECTROMAGNETISM/energy is gravity.
By Frank Martin DiMeglio
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
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!!!
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!
You are very welcome
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
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 !!
Mine also
I haven't been so engaged in the physics lecture as much as I have been watching this video. Absolutely fascinating!
I've been trying to find a decent class lecture on this for so long. Thank you, it's been very helpful.
most inspiring teacher ever! thank you Mr.Lewin for still inspiring us.
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
1. Excellent demos.
2. Very thoroughly explained, whereby anyone can understand the concept!!!!
thank you
you are welcome. I am high school physics and biology teacher. I find your lectures (where applicable to my lesson) very useful.
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 😃
Glad to hear that
@@lecturesbywalterlewin.they9259 Sir is there any entrance exam for getting into MITs and if yes then , are those exams tougher than jee advanced ?
@@shauryasaxena7791 Yeah SAT. Its easier than Jee.
@@shauryasaxena7791 none is tougher than jee advance and mit don't have specific exam nowadays
@@overthinker69069 well yes and also the gaokao exam
His lectures have an awesome flow, love them.
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
thanks for your kind words
My teacher makes me watch these before every class because this guy actually knows what he is talking about.
crazy bout your teacher
Your grandmother is really awesome...🙏
We can't expect this dedication in India for some hundred years from now.....🙏
Yes majorly because once which was the center of education of world, India, was ruined by two colonizations back to back.
Ultimate physics teacher with real life (example)stunts in hand. We miss you sir! but we follow your lectures🤘
All the best
Nothing is as good as physics prof... thanks for making us understand everything so easily 🙏🏻
Thank you, Mr Lewin. I will remember this for life
Always a great lecture. Cirurgical precision. And it’s not negotiable! Thank u for the masterpiece of of your entire career.
My pleasure!
Thank you! I love learning from the best! What a world we live in to have this opportunity!
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 ...
So FASCINATING😍. I love this guys lectures.
Respected Walter sir , I am proud of you that my physics teacher recommends you and he teaches us after seeing your lectures🙏🙏🙏🙏
That's why as a pilot I experience the gravity towards my feet when I do a tight turn (coordinated of course). Great lecture!
19:00
This explains everything
the basic idea behind centrifuge just blew my mind.
It was like.... I mean..oh god! I can't express it!
Being a Physics faculty i had drawn a lot of inspiration from you professor.
SIR CAN I CRACK NEET PHYSCIS BY WALTER LEWIN SIR
Centripetal acceleration is cool. Your explanations and demonstrations are even cooler. Thanks!
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
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.
In India we are taught this in class 11 😂 btw great explanation ❤️❤️🔥
Professor Lewin is Best teacher on CZcams ❤️❤️🔝🔝👌👍 love respect from india
This is a far better resource than oxford textbooks, no mistakes in these videos!
10:31 legend
czcams.com/video/raurl4s0pjU/video.html
that's actually pretty simple to do
@@nabhchandra_ not for every one
Great..excellent..all are very small word for you.
You are unique, thank you sir.
Thanks for providing all these amazing experiments for free.
Open chested Salute to you Sir 🙏
Lots of love and Thanks from India 🇮🇳❣️🇮🇳
How many lucky students are sitting. I wish our teachers were like this
Our teachers only disappoint us and ruin our future.
Soooooo good. Thank you very much Professor🙏🏻
Sir you always have a unique way in your every lectures, I HAD JUST FALLEN IN LOVE WITH PHYSICS because of you.
Thanks 😊
Love your anima and lectures. Thank you proffessor!
Sir, you save the lives of physics students everyday! I want to simply thank you.
:)
19:00 absolutely genius!
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
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 ❤
Wow what a lecture ⚡😘
Whatta lecturer💫
I was so dumb , few months back my mentality for physics was not like today. Thanku so much sir Lewin ❤️😇
It takes me years to actually know this that physics can be fun. Credit goes to you legend ❤️ 🙏thank you sir
In my mind you are the very kind father to me not just a teacher. Wish bests for you.
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❤️
Sir you are the epitome for love towards physics ❤️ I respect you.
This is just a fantastic series of lectures. Professor Lewin why couldnt you have taught me physics in school!
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!
The person who swings around experiences a centrifugal force that pushes him outwards, but the string or the rotating platform will keep him in place. Thus the person perceives gravity outwards
Thank you for your answer.
Follow up: Does that mean you would draw a centrifugal force in a force body diagram of the person being swung around?
If I am outside and I drew a free body diagram there would be only 1 force (the centripetal force pointing to the center of the circle). If the person on the centrifuge would draw a free body diagram he would draw 2 forces: the centrifugal force radially outwards and the force that the wall exerts on him. This force has the same magnitude but it is in opposite direction so that the net force on the person is ZERO.
It depends on your frame of reference. Read my earlier msg
Lectures by Walter Lewin. They will make you ♥ Physics. Hi friend take an object and make it go circular motion then in the free body diagram of that object u will draw only centripetal force towards the centre . Now u sit on that object then u will experience centrifugal force ...
Professor, is there any scholarship exam that I can apply for to study at MIT?
How to get into MIT?
czcams.com/video/hRp3ND-fBNw/video.html
SAT Scores and GPA (www.prepscholar.com/sat/s/colleges/MIT-SAT-scores-GPA)
The average GPA at MIT is 4.13. This makes MIT Extremely Competitive for GPAs.
The average SAT score composite at MIT is a 2220 on the old 2400 SAT scale.
On the new 1600 SAT, this corresponds to an average SAT score of 1520.
Love his elucidation... It's divine❤❤❤
Never understood any physics this better.
Thank you Dr. Lewin
:)
Hi, and thank you.
Ramiro Gonzalez hi
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?
At any point in time, t, there is an centripetal force on an object which is mv^2/R. v is the speed at time t, R is 1/"curvature" at time t. The direction of the force is perpendicular to its velocity (it's pointing towards the center of an "imagined" circle. The centripetal force is ONLY zero if the object moves along a straight line as R is then infinity.
no centripetal acceleration is inverse with radius BUT ONLY IF the tanget speed is the same for ex: if you're driving a car at 34m/s and try to take a 24 meter radius turn your acceleration would equal 48m/s^2 according to a=v^2/r,
and if you try to take a 33 meter turn at the same speed your acceleration would be 35m/s^2 .
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
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.
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.
first get a PhD in Physics in the very best Univ that will accept you. Then get a postdoc position at a major University and make a name for yourself in doing fundamental research which the world will pay attention to. Then apply for a Professorship at MIT when they publish that they have an opening.
Lectures by Walter Lewin. They will make you ♥ Physics. I am a undergraduate student and i want to become a teacher just like you...I want to share my knowledge. ..views on physics. .....thank you sir for these videos
:)
wow .. good luck
Soooooo Hard but good luck 👍🏼👍🏼👍🏼
19:00 superb
Thank you professor Lewin for such beautiful sessions.. Grateful to have his lectures free of cost. Thank you sir..
The best part about your lectures are your demonstration of experiments.
Like I had studied everything about those centrifuge and buckets of water and got bored with those diagrams and eqns😕 but today when you actually showed the experiments, I was like it's damn fun. 🤩
Perfect explanations! Thank you from Israel..! (:
Allah hu akbar
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.
it differs for different people
Thanks
No matter the age, you need to completely immerse yourself in the material. So far I am loving physics; however, it is the hardest subject I've ever encountered thus far which probably has more to do with my professor's pedagogy than the subject alone.
Best physics professor on CZcams!!!!
Grateful to have his lectures free of cost. Thank you sir.
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
2:13
Did anyone notice a fluctuation in 'T'
Omega=2π/T
This 'T'
???😱😱
His lectures are simple ,he is simple yet they are the best.
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. ❤
I'm really curious as to what happens when the video cuts.
He cuts out the bits where physics doesn't work properly or he breaks the laws of thermodynamics. All part of the great conspiracy.
Imagine having your sleeping quarters in the middle of a wheel :0
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!
How a man can be a physics teacher and not boring?❤️, love from Pakistan.
i thought there was no thing as centrifugal force ...now you introduced that concept through perceived gravity ...now im confused???😲😲😕😵
+Bhoovesh Waran In My reference frame as I see something rotate in MY frame there is NO centrifugal force but there is a centripetal force. End of story. I cannot help you anymore. I NEVER even use the words centrifugal force in my lectures.
+Lectures by Walter Lewin. They will make you ♥ Physics. But how does gravity act outwards?
+Bhoovesh Waran I do not know what you mean by "outwards". I fear that your background in physics is insufficient to watch my lectures. I cannot help you any further. The grav acc is ALWAYS down. That's mother nature - we cannot change that. However, you may always choose what you call + and -- in your coordinate system. If you call vertically up +y, then grav acc pn an object is ALWAYS --g. If you call vertically up --y, then grav acc is always +g. The choice of signs does NOT affect in any way the physics. Good luck! .
+Bhoovesh Waran "perceived" gravity can be in any direction and it can change direction fast.
If an astronaut were in a fast rotating satellite, (s)he would perceive gravity (which is NOT real gravity) "outwards from the center of the circle of the rotation. The direction would change continuously radially outwards - 360 degrees in the period of the rotation. Since the frame of reference of the astronaut is the rotating frame of reference, astronaut (s) will "experience" a centrifugal force (outwards).
"Lettuce fill this with water..." hehehehehehe
I see what you did there.
Thank you professor Lewin for such beautiful sessions.
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!
Dr. Lewin, your lectures are just amazing. If you had to chose between IE Irodov and HC Verma, which one would you chose?
lol.... physics is not about JEE boy!!
😂😂😂😂😂😂
xD
Lol bro ! what a jerk
is there connection between physics and chemistry
YES, use google
Lectures by Walter Lewin. They will make you ♥ Physics. ok
:)
Definitely YES ! The best example is THERMODYNAMICS .
Chemistry is just applied physics.
It's really good...and the energy he has is unbelievable...u increases the curiosity of physics in our life
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..💯
I have no idea why I'm here. I'm only in 6th grade and this makes no sense.
you might as well enjoy it!
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
I saw some of his lecture s in You tube . I think He is ULTIMATE PHYSICS TECHER in the World! Even though after his retirement. He is very active teacher.
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.