Es la primera vez que veo este tema a una escala nanoscópica. Estoy ansioso por entender todo esto, pero lo tendré que ver varias veces. Gracias MIT por la calidad y claridad de la información que brindan de forma gratuita.
im so confused ... why is it not possible to engineer superlubricity at the macroscopic scale? .... fascinating lesson, thank you so much! you are an excellent teacher
@@LeethLee1 To keep it consistent I suppose I should wait another 2 years to reply to this, but I'm afraid I would forget. You left-handed people are weird though, I'm sorry
Very interesting video. I learnt a lot. Physics is so important to understand. Understanding Physics is like reading poetry. Congratulations for such brilliant clear explanation !! 🏆
Can somebody please explain to me about the bottom part of the animation at 19:40? I think I kind of get the upper part that it is the interaction between the atom hanging on the spring and the substrate (please let me know if it isn't), but I don't get the bottom part. Thanks in advance!
@@ExplosiveBrohoof If the mass is in simple harmonic motion, then x is sinusoidal in time. F = kx. So, yes, the force depends linearly on position and sinusoidally on time.
Sound simple initially until it went like someone explaining his thesis. My brain can't understand this much but I appreciate your teaching style. Thank you for uploading this video. 😅😅
[8:44] though we all are born from the cause of friction. Without friction, there is no satisfaction. I am now wondering how much atomic layer do I lose whenever I start ... :-)
Yeah, they should have mentioned what they meant. As far as I understood, if you look at it as a macroscopic spring on a mass, that is the potential energy of the spring as we slide the spring in the positive x direction with a constant velocity. Microscopically, it would be the periodic change in the electrostatic forces between the atom on the spring and the atoms on the surface.
why is friction independent of contact area? does it have to do with pressure and if the mass is spread out over a smaller area, there is a smaller pressure to compensate for large contact area or something like that?
Get on a 10/12 pitch roof, stand flat footed, then compare it to putting your weight on your toes. If you believe surface area doesn’t matter, why can I stand on the roof on my toes yet when I spread my weight over the surface area of my entire foot, I slide down
Why is the Golden Ratio used? Why not take a=d/2 such that when one atom is at maxima, the other is at minima. Wouldn't this be the second case? Why complicate it by using a golden ratio. Now I know Golden Ratio is 1.6 which is something what I am trying to say here, why not just make it 1.5?
He is writing forwards, the camera is capturing it backwards, and the software and hardware reverses it. See lightboard.info for more info on how this is done.
Cannot say I understood 100% of this lecture but it was fascinating to watch and learn about frictions. Thank you for the video.
Es la primera vez que veo este tema a una escala nanoscópica. Estoy ansioso por entender todo esto, pero lo tendré que ver varias veces. Gracias MIT por la calidad y claridad de la información que brindan de forma gratuita.
im so confused ... why is it not possible to engineer superlubricity at the macroscopic scale? .... fascinating lesson, thank you so much! you are an excellent teacher
Yes that was freaking cool :D Writing backwards was just the cherry on top for the learning. Many thanks!
You may be willing to check this out
lightboard.info/
They explain how they make use of the lightboard system :)
all of them are obviously left-handed writing effortlessly backwards, there is no other way..
He is writing on a mirror.... no?
@@Postermaestro I'm left handed, it seemed normal to me lol
@@LeethLee1 To keep it consistent I suppose I should wait another 2 years to reply to this, but I'm afraid I would forget. You left-handed people are weird though, I'm sorry
Very interesting video. I learnt a lot. Physics is so important to understand. Understanding Physics is like reading poetry. Congratulations for such brilliant clear explanation !! 🏆
best lecture of this course so far!
Going forward I'll try to find out more on friction, for now this has been very Illustrative.
Wt about ur channel.did u register
Can somebody please explain to me about the bottom part of the animation at 19:40? I think I kind of get the upper part that it is the interaction between the atom hanging on the spring and the substrate (please let me know if it isn't), but I don't get the bottom part. Thanks in advance!
I have the same question
Why is the force of the spring assumed to be linear? Isn't it sinusoidal?
The force is linear because its magnitude depends on the displacement from equilibrium. The position, velocity, and acceleration are all sinusoidal.
@@theintrepid7583 But F = mA, and mass is invariant. If acceleration is sinusoidal, wouldn't that make the force sinusoidal as well?
@@ExplosiveBrohoof
If the mass is in simple harmonic motion, then x is sinusoidal in time. F = kx. So, yes, the force depends linearly on position and sinusoidally on time.
Sound simple initially until it went like someone explaining his thesis. My brain can't understand this much but I appreciate your teaching style. Thank you for uploading this video. 😅😅
[8:44] though we all are born from the cause of friction. Without friction, there is no satisfaction. I am now wondering how much atomic layer do I lose whenever I start ... :-)
Animals don't really satisfied mating and yet they are still born.
He’s so good at writing backwards!
Anyone know the math background he bases himself on to affirm there are numbers more irrational than others ? What is this scale of irrationality?
I am an utter layman but could one imagine that quantum friction is the hidden force responsible for the expansion of the universe?
WHAT IS THE EQUATION, PLEASE
*paused at **17:19* Am I supposed to know what a potential is at this point? Surely not?
Yeah, they should have mentioned what they meant. As far as I understood, if you look at it as a macroscopic spring on a mass, that is the potential energy of the spring as we slide the spring in the positive x direction with a constant velocity. Microscopically, it would be the periodic change in the electrostatic forces between the atom on the spring and the atoms on the surface.
@@cocoa1996 This is very helpful, thanks
what age group are these videos targeted to?
Undergraduate level
70+
why is friction independent of contact area? does it have to do with pressure and if the mass is spread out over a smaller area, there is a smaller pressure to compensate for large contact area or something like that?
This was explained in video 6.1 about contact forces
Get on a 10/12 pitch roof, stand flat footed, then compare it to putting your weight on your toes. If you believe surface area doesn’t matter, why can I stand on the roof on my toes yet when I spread my weight over the surface area of my entire foot, I slide down
I don’t agree
Bigger surface area less pressure. They both matter.
"ua-cam.com/video/Rcih4jIaNvI/v-deo.html" This video has a great simulation regarding this model
STOP SCROLLING THROUGH THE COMMENTS AND WATCH THE LECTURE
just kidding
Why is the Golden Ratio used? Why not take a=d/2 such that when one atom is at maxima, the other is at minima. Wouldn't this be the second case? Why complicate it by using a golden ratio. Now I know Golden Ratio is 1.6 which is something what I am trying to say here, why not just make it 1.5?
The Golden ratio is the hardest irrational number to approach with fractions composed by integers.
He is Not left-handed.
too much information for this lecture
This is dank shit
Is anyone else weirded out by the fact that he seems so comfortable writing backwards?
He is writing forwards, the camera is capturing it backwards, and the software and hardware reverses it. See lightboard.info for more info on how this is done.
Duuuh
🙃 الكلام معكوس