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I recently created a Patreon account for people who want to help support my channel. The link is on my TH-cam home page. Also, in case, you have not already seen them, I uploaded several other videos recently. As always, for each video that you like, you can help more people find it in their TH-cam search engine by clicking the like button, and writing a comment. Lots more videos are coming very soon. Thanks.
+Physics Videos by Eugene Khutoryansky I m watching your video 9th class and now I m 1st year(11th class) and still watching................. Your physics videos, animations and explanation are the best...............
Physics Videos by Eugene Khutoryansky You're one of the best teachers I've had in physics, but somethings been boggling my mind for a while and this video is a perfect opportunity to ask. Could you please explain how the smaller object when colliding with the bigger one(2.25) does not stop. I know in real life it would bounce off but according to Newton's laws of motion it shouldn't. According to Newton's third law, there should be an equal and opposite reactionary force on the smaller ball when it applies a force on the bigger ball and since force is equal to the change of momentum, when the bigger ball applies the equal and opposite force, the smaller ball should stop as the force it exerts is equal to it's momentum. This doesn't happen in real life. Something that may help you that I've thought of, is from a different example. Consider the smaller ball now stationary, and the bigger ball is moving toward it at a constant velocity. Same situation but the roles switched. When the bigger ball hits the smaller ball, I used to think the bigger ball should stop as the smaller ball produces an equal and opposite force to stop it. But then I realised that the bigger ball does not have to exert its full momentum onto the smaller ball, but only enough so that the move at a similar speed. So the momentum of the larger ball only decreases by a smaller amount as it takes less force to get the smaller ball moving at the same speed. That's my reasoning, unfortunately it does not explain what I mentioned earlier. My reasoning lead me to think that the smaller ball has to exert a larger force than its momentum can give to the larger ball, but it then gets cancelled out when the larger ball exerting the same amount of extra force to the smaller ball making it move in the opposite direction. However the reasoning mentioned in the last paragraph alludes to there being a conservation of velocity which definitely sounds untrue. I hope you read and understand my long winded messy post and give some kind of solution based on what you can understand of what I am saying, I hope I'm not wasting your time, sorry :)
You can help translate this video by adding subtitles in other languages. To add a translation, click on the following link: th-cam.com/users/timedtext_video?v=PNHSIEO-KOQ&ref=share You will then be able to add translations for all the subtitles. You will also be able to provide a translation for the title of the video. Please remember to hit the submit button for both the title and for the subtitles, as they are submitted separately. Details about adding translations is available at support.google.com/youtube/answer/6054623?hl=en Thanks.
VERY well presented. Being a young adult yearning off the knowledge of theoretical physics, I found this video to be sufficient and explanatory. Great work, Eugene!
@ Not necessarily true. I've earned a degree in Physics but getting a Doctorates in Electrical engineering. In other words, there is a physics background even if it's scope is just courses in physics. Electrical engineers are required to take physics as part of their program.
question..... if the ball rotating around an axis has a certain linear momentum, by changing its distance from the center, the linear velocity has to be changed (in order to keep angular momentum constant) which means that the kinetic energy is changed without any external energy source and it seems to be violation of energy conservation. than how can that be possible ...please explain it @Eugene
To change the ball's distance from the center, a force is applied, thereby adding or removing energy from the system. The energy is being transferred to or away the source of the force.
Hi Eugene, very nice video! Could you make a video about the dzhanibekov effect (instability when rotating around the intermediate axis of rotation). I can't grasp my head around it how angular momentum is conserved during this effect.
Suddenly I get the appropriateness of 'The Blue Danube' (think 2001). Docking with the space station is an exercise in balancing angular momentum as well. Bravo!
This lecture is like listening a speech in a Royal Party (by closing eye) Feels like present in the 1st Class Prog. in something like the Titanic. Excellent Video
@@EugeneKhutoryansky I am very surprised by your reply sir . And like your million subscribers even I wish to be speaking with you sir (I also know that it wouldn't happen 😅. If that happens means I will reach HD1 galaxy itself sir .And within 272 days I will complete my schooling and I will be free for 3 to 4 months after that.... So due to that (it may sound stupid) can you be my greatest and wonderful and genius physics teacher?? Thank you once again sir for your free high quality videos we students are very much grateful to you.. Consider the first paragraph sir 😄
A very nice and clear explanation of a rather confusing topic (angular momentum). Thanks so much! Ill definitely be passing this video along to my students.
Hello Mr. or Ms. Khutoryansky, First of all your videos are amazing. Thanks to them i really started to enjoy physics , because now i can visualize the physical concepts and notions much easier and they are nomore boring ,abstract stuff. I just wanted to ask the following : Shouldn't the parallelogram in 5:08 and following 20 seconds be a triangle so the angular momentum ( the field of the triangle ) stays constant ? Thank you very much again.
@@EugeneKhutoryansky thank you, actually. Please make videos more on physics with great animations and everything. Especially about electricity, mechanics and thermodynamics. I know you will deliver the best.
Please allow the download button on this video....then I can watch it another few hundred times on my television. Your videos are always high quality due to the clear and concise instructions. Thanks you for putting the time into educating everyone.
What happens when the distance between the rotaing objects goes to infinity? In that case the areas seems to go to zero. Is angular momentum no longer conserved at infinity?
Angular momentum is a measure of the sum total of the cross product of the position vector to, and the linear momentum of each particle in a system, with the position vector taken relative to a common reference point. It is a quantity that is conserved and is used as a method for calculating the effects of interactions among objects within a system, when there are no external torques.
Thanks for the explanation. I am still confused, however, whether angular momentum and linear momentum are interchangeable. Can you explain more, please?
They are analogous, but not interchangeable. They are both separate quantities of motion that each are conserved in their own right. Linear momentum is defined as the product of velocity and inertia (i.e. mass), as a way to quantify the time-cumulative effect of a force. Angular momentum considers the linear momentum vector and the radius vector from a reference point, as a way to quantify the interactions that would cause rotational motion. Radius cross product linear momentum, is how we define angular momentum. You can have situations where angular momentum is conserved, while linear momentum isn't, but not vicea. They both are ultimately conserved in the universal sense. Conservation of linear momentum applies when there are no net external forces acting on the system. Either external forces add up to zero, or aren't present in the first place, or a situation happens so quickly that the external forces can be neglected (like a collision while subject to gravity). Conservation of angular momentum applies when there are no net external torques acting on a system, relative to the reference point about which angular momentum is defined. So it is OK that there be radial external forces directed parallel to the radius vector when considering conservation of angular momentum, since these forces don't apply a torque to the system. It is the external forces that are not parallel to the radius vector from the reference point, that need to be either excluded or nullified by other external forces, in order for conservation of angular momentum.
@@benjaminsisko9250 Yes. Angular momentum requires you to assign a reference point, which is usually selected as the point containing the axis of rotation. You will get a different answer if you assign a different reference point. So a problem may specify an origin to use, and in that case you need to use the point specified. Otherwise, you choose the point to assign as the reference point. It is arbitrary what point you chose to assign, although it is usually the case that one particular point will make the math a lot more convenient, and you'd be "asking for trouble" to pick a different point.
@@carultch The reference point (center point) I pick must be in inertial frame, 'coz if I choose an accelerated frame, then the situation above does not apply, right?
@@benjaminsisko9250 Depends on what kind of accelerated reference frame we are talking about. If the reference frame has a constant linear acceleration, you can use the equivalence principle and treat the apparent inertial force the same way as you would treat any other gravitational field if you were in an inertial reference frame. (Put aside the general relativity meaning of inertial reference frame that requires excluding gravitational fields, and stick to the Galilean/Newtonian meaning of the term, for our purposes). By contrast, if we are talking about a rotating reference frame, you are much better off looking outside of it, and selecting a point in the inertial reference frame. The Coriolis effect will appear to act as if it is an external torque on any system within a rotating reference frame, which will rule out using conservation of angular momentum unless you also account for the effect.
When the particles repel each other while rotating ,they spin slower to keep the angular momentum constant. But how do we prove that the angular momentum of the universe is always constant during any interaction?
+Ibrahim Chahrour, this is a consequence of Newton's Laws of motion. Since for every force, there is an equal and opposite force, and F = mA, the net consequence is that momentum and angular momentum must be conserved. We also know this through experiment, in that we have always found momentum and angular momentum to be conserved for every experiment we conducted.
as far as i know that acceleration is the main factor responsible for the velocities changes but in the video,exactly after the perfectly collision in the situation where 2 objects moved in two different directions, i see that the velocity vectors magnitude have simultaniously changed. So my question is what acceleration have caused the velocities magnitude change like that ?
It is just how we chose to define the direction of the angular momentum vector. This is just a social convention, not a law of physics. If we chose to define it the other way, all the observable data would still be the same.
"Linear momentum is also conserved, since we started out with a linear momentum of zero and ended up with a linear momentum of zero." ~deeply refers to "us" idly sitting, watching this video out of boredom.
The area of the parallelogram does not change because the lengths of the base and the height does not change. Details about the area of a parallelogram are in the following link. en.wikipedia.org/wiki/Parallelogram#Area_formula
In the last described image( two rotating particle),the total angular momentum of the rotation is 2* area of the two parallelogram.but how it the same before and after the rotation?why It is not zero?
One way to define inertia is mass's tendency to keep an individual object's linear (and angular) momentum. Linear momentum can be said to be the required quantity that requires an external force and some time in order to "destroy" it or increase it.
@@mangaka08 I am totally satisfied with your explanation. Thanks . Just wanted know Can we call Momentum rate of motion ? or work done? or type of energy? or force?
@@LinuxLuddite Kinetic energy is significantly more sensitive to velocity than it is to mass. KE also ignores the direction of velocity, because squaring velocity is a self dot product that eliminates the direction. Momentum is equally sensitive to both terms, and maintains the same direction as the direction of velocity. Start with mass, i.e. inertia. Integrate with respect to velocity from rest once, and you get momentum. Integrate with respect to velocity from rest a second time, and you get kinetic energy. This is where the 1/2 comes from in the kinetic energy formula.
We need to take into account the momentum and angular momentum of all the subatomic particles in the material providing the friction, and then we see that the momentum and angular momentum is still conserved.
+John Lux, thanks for the compliment. In reply to your question, when the Sun exerts a gravitational attraction on the Earth, the Earth exerts a gravitational attraction on the Sun. I show an animation of this in my "Laws of Motion" video. Thanks.
You're one of the best teachers I've had in physics, but somethings been boggling my mind for a while and this video is a perfect opportunity to ask. Could you please explain how the smaller object when colliding with the bigger one(2.25) does not stop. I know in real life it would bounce off but according to Newton's laws of motion it shouldn't. According to Newton's third law, there should be an equal and opposite reactionary force on the smaller ball when it applies a force on the bigger ball and since force is equal to the change of momentum, when the bigger ball applies the equal and opposite force, the smaller ball should stop as the force it exerts is equal to it's momentum. This doesn't happen in real life. Something that may help you that I've thought of, is from a different example. Consider the smaller ball now stationary, and the bigger ball is moving toward it at a constant velocity. Same situation but the roles switched. When the bigger ball hits the smaller ball, I used to think the bigger ball should stop as the smaller ball produces an equal and opposite force to stop it. But then I realised that the bigger ball does not have to exert its full momentum onto the smaller ball, but only enough so that the move at a similar speed. So the momentum of the larger ball only decreases by a smaller amount as it takes less force to get the smaller ball moving at the same speed. That's my reasoning, unfortunately it does not explain what I mentioned earlier. My reasoning lead me to think that the smaller ball has to exert a larger force than its momentum can give to the larger ball, but it then gets cancelled out when the larger ball exerting the same amount of extra force to the smaller ball making it move in the opposite direction. However the reasoning mentioned in the last paragraph alludes to there being a conservation of velocity which definitely sounds untrue. I hope you read and understand my long winded messy post and give some kind of solution based on what you can understand of what I am saying, I hope I'm not wasting your time, sorry :)
Meeharbi N the reaction is the one object stopping. the force brings the object to zero so there still is a equal and opposite force but it's just the perfect amount to stop it and not have the ball move in another direction
Meeharbi N it depends also on how elastic the collision is and if energy is lost in the collision. it does happen all the time so you saying it doesn't is simply wrong
You are understanding is incorrect. Please to refer to F=ma . let m1 be the smaller ball and m2 be the bigger ball and also let's assume m1= 1kg and m2= 10kg . then after collision between the balls it is abvious the smaller ball will bounce back with greater acceleration that the bigger ball. In this case, by the equation f=ma , we can safely say that it's acceleration (lets assume m1 acceleration be a1 and m2 acceleration be a2) wil be in the ratio 10:1 so as to show f=m1.a1 = m2.a2.
All the music in this video is from the free TH-cam audio library, and the names of the songs are the following. Moonlight_Sonata_by_Beethoven Road_to_Moscow Blue_Danube_by_Strauss
The short answer is, it's just a convention. The long answer is, that we opt to define angular quantities perpendicular to the plane of rotation, to eliminate the number of arbitrary options we have to choose. We choose the axis of rotation instead of the plane of rotation, so that 360 degrees worth of arbitrary options turn into just two arbitrary options. We chose the right-handed option, for consistency with the way the majority of threaded fasteners work: "righty tighty/lefty loosey".
Thank you very much for this video! I have a question, is there a way to know why the angular momentum is at 90°? (Momentum that is apparently to the right of the object, assuming that the direction to which the object moves is the "front"). Edit: I have no idea, but if I had to guess, I'd say it's like the "residual force" from the axis, which would make the orbits to slowly lose force.
Thank you very much for this high quality content. You have a really good manner to explain this theoretical concept very easily. I read about moment of momentum before. I had understood the mathematics behind this object. But I could not figure out correctly how to physically represent it in real life, and the consequences of this concept. For instance, the increasing or decreasing velocity with the opposite decreasing or increasing of rotation radius. With your video is definitely very clear. There is so many other subjects you could represent and explain like this.
Why does angular momentum point 90deg relative to the planes toward the observer in clockwise rotations and 90deg away from the observer in counterclockwise rotations? I never got that, why that particular direction?
+Raymond Fernandez, actually, it is the reverse, but in reply to your question, this is just an arbitrary convention. We could have just as easily defined it the opposite way, so long as we also defined the direction for the torque arrow in the same way.
The reason why we opted to assign the direction of angular quantities to be along the axis, is to reduce the number of arbitrary options we had to choose. It is more a matter of bookkeeping and convention than anything physical actually happening in that direction. If we opted for a direction in the plane of rotation, we'd have 360 degrees worth of options to choose from, which is an infinite continuum that gets us nowhere. By choosing the axis of rotation, we now have only two options from which to choose. We either get to define it so CCW is toward the observer, or CW is toward the observer. We opted for CCW being defined toward the observer, for consistency with how the majority of threaded fasteners work and we use right-handed coordinate systems to be consistent.
+Naratuga T, an electron has a negative charge, and a positron has a positive charge. The sum of the charge of an electron and a positron is therefore zero. If these two particles annihilate each other, the total net charge is zero both before and after the reaction.
Why did we define the standard such that fermions have half-integer spin? Why not just cut the reference spin value in half, and give fermions a spin number of 1, and bosons a spin number of even integers? I'm not trying to ask rhetorically, I really would like to know what was behind setting up the standard for spin numbers in quantum mechanics, that caused half-integer spins to exist.
In the linear momentum example I get shocked: vectors addition leads to incoming small ball crashing with a big green one happening ā = -ā + 2*ā , the small gets away from it were coming and the other have "twice more momentum than the original"!!... so, What will happen if the green one crashed another small one in chain giving all its moment? It will result in an overall momentum of and incoming ball with momentum ā which ends in a exactly alike ball traveling with momentum 2*ā !!, which is impossible from conservation of energy!!... so my question is: Is really possible to have this ā = -ā + 2*ā collision??? My intuition says from energy conservation also must happen that (incoming momentum)^2 = (final momentum)^2, so this example leads to a^2 = a^2 + 4*a^2 which is obviously wrong, so I think that actually the scenario is impossible (if my assumption is right). Also about the parallelogram example refered to an arbitrary point: since the velocity is constant and the radii of the another vector changes more than the cosine of the angle, I believe that the area is not constant.. if the ball have travel to infinity far away the area will certainly be infinite, differently if the vector is rotating towards the point were the parallelogram is always the same. Also if something is not rotating, I believe its angular momentum is zero, so the linearly travelling ball refered to an arbitrary point is not a good example.
+Max Webster, it is any point that we pick in space. No, this point does not exert a force on the particle. It is just that for any point we pick in space, the angular momentum around that point, as described here, will remain constant.
The first thing I don't understand is that the total amount of electric charge in the universe is always constant. When I charge a capacitor, and then connect it to a heating coil, it discharges and converts the electric charge into heat. So where did the electric charge go, since it was converted into molecular movement (=heat) in the heating coil?
+Seegal Galguntijak, when a capacitor discharges, the excess electrons on the negative plate simply move to the positive plate. As they do this, they collide with other atoms, and their energy of motion is converted into heat.
Eugene Khutoryansky I see - never thought of that. Of course the amount of charged particles in a capacitor itself is always the same, whether it is in a charged or discharged state.
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My wish is to be with scientists and give you new theories and I have some theories plz 🙏🙏 help me to give my theories to world love from Pakistan.
Türkçe diline nasıl çevireceğiz.
@@TURNON111write a Article and send to a good journal for publication..
@@murugan5280 already done it but no one even published worldwide
Dear Eugene! Wowww! That's beautiful and perfect job! Congratulations
I recently created a Patreon account for people who want to help support my channel. The link is on my TH-cam home page. Also, in case, you have not already seen them, I uploaded several other videos recently. As always, for each video that you like, you can help more people find it in their TH-cam search engine by clicking the like button, and writing a comment. Lots more videos are coming very soon. Thanks.
+Eugene Khutoryansky You're the best, hands down best youtube subscription. Don't stop making videos!
you shold put the link to the patreon in the description of the videos.
awesome video!
+Physics Videos by Eugene Khutoryansky I m watching your video 9th class and now I m 1st year(11th class) and still watching................. Your physics videos, animations and explanation are the best...............
You and Salman Khan ( from KhanAcademy) rule when its about illustrative and clear e-learning.
Physics Videos by Eugene Khutoryansky
You're one of the best teachers I've had in physics, but somethings been boggling my mind for a while and this video is a perfect opportunity to ask. Could you please explain how the smaller object when colliding with the bigger one(2.25) does not stop. I know in real life it would bounce off but according to Newton's laws of motion it shouldn't.
According to Newton's third law, there should be an equal and opposite reactionary force on the smaller ball when it applies a force on the bigger ball and since force is equal to the change of momentum, when the bigger ball applies the equal and opposite force, the smaller ball should stop as the force it exerts is equal to it's momentum. This doesn't happen in real life.
Something that may help you that I've thought of, is from a different example. Consider the smaller ball now stationary, and the bigger ball is moving toward it at a constant velocity. Same situation but the roles switched. When the bigger ball hits the smaller ball, I used to think the bigger ball should stop as the smaller ball produces an equal and opposite force to stop it. But then I realised that the bigger ball does not have to exert its full momentum onto the smaller ball, but only enough so that the move at a similar speed. So the momentum of the larger ball only decreases by a smaller amount as it takes less force to get the smaller ball moving at the same speed. That's my reasoning, unfortunately it does not explain what I mentioned earlier. My reasoning lead me to think that the smaller ball has to exert a larger force than its momentum can give to the larger ball, but it then gets cancelled out when the larger ball exerting the same amount of extra force to the smaller ball making it move in the opposite direction.
However the reasoning mentioned in the last paragraph alludes to there being a conservation of velocity which definitely sounds untrue. I hope you read and understand my long winded messy post and give some kind of solution based on what you can understand of what I am saying, I hope I'm not wasting your time, sorry :)
Beethoven - Moonlight Sonata (1st Movement)❤️. Let's go!!
Not to mention 'On The Beautiful Blue Danube', which always transports me to a Pan-Am space shuttle docking with the space station...
the best explanation on angular momentum on youtube,period
Thanks for the compliment about my explanation.
You can help translate this video by adding subtitles in other languages. To add a translation, click on the following link:
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Thanks.
Your video is older than the Bugatti Chiron. Wow
VERY well presented. Being a young adult yearning off the knowledge of theoretical physics, I found this video to be sufficient and explanatory. Great work, Eugene!
So are you a physics professor or something? How do you know all this stuff and how do you manage to describe it all in such an intuitive manner?
+Virusnzz He's an Electrical Engineer!
@ Not necessarily true. I've earned a degree in Physics but getting a Doctorates in Electrical engineering. In other words, there is a physics background even if it's scope is just courses in physics. Electrical engineers are required to take physics as part of their program.
That is so untrue lol.
@@Spacetime_ghost richard feynman started as a biologist
@@elijahjflowers so that proves that most people who don't do physics can explain it better?
Amazing thank you, keep going on
Glad you liked it. More videos are on their way.
Shining Star of Physics.
Always stay blessed...
Thanks!
Literally learning this right now in my physics course. Thank you!
question..... if the ball rotating around an axis has a certain linear momentum, by changing its distance from the center, the linear velocity has to be changed (in order to keep angular momentum constant) which means that the kinetic energy is changed without any external energy source and it seems to be violation of energy conservation. than how can that be possible ...please explain it @Eugene
To change the ball's distance from the center, a force is applied, thereby adding or removing energy from the system. The energy is being transferred to or away the source of the force.
you deserve much more views I think it's bcz of you long channel name -a simple advice from a regular viewer thanks a lot
Karan Agarwal absolutely
It’s his name.
@@cssstylescommand4 "Physics Videos by [Name]" could be shortened to just this name
@@ThomasBomb45I think a bit longer but self-explanatory channel name would be "[Name]'s Physics".
you cleared my concepts on conservation of linear momentum sir,
+Vineet Dubey, Glad I was able to help.
Hi Eugene, very nice video! Could you make a video about the dzhanibekov effect (instability when rotating around the intermediate axis of rotation). I can't grasp my head around it how angular momentum is conserved during this effect.
My favorite channel ❤ قناتي المفضلة
Glad to hear that. Thanks.
Suddenly I get the appropriateness of 'The Blue Danube' (think 2001). Docking with the space station is an exercise in balancing angular momentum as well. Bravo!
Best explanation I have ever seen in my life
Thanks for the compliment about my explanation.
I genuinely love this channel!
Thanks. I am glad to hear that.
This lecture is like listening a speech in a Royal Party (by closing eye)
Feels like present in the 1st Class Prog. in something like the Titanic.
Excellent Video
Glad you liked my video. Thanks.
Wow one of the best explanation
Thanks a lot ❤❤❤❤
Thanks for the compliment. I am glad you liked my explanation.
Best ever explanation I found on the net! Great Work! Pls. Keep going.
Thanks. I am glad you liked my explanation. More videos are on their way.
You really are the bollocks Eugene, I have watched all your videos several times over now. Wonderfully accessible 👍
A fantastic educational video as always
Your videos are masterpieces
Thanks for the compliment.
2:25 but in this animation momentum is not fully transferred to bigger ball but smaller ball bounced why ??
Literally!!!!!! Hats off miss
Thanks.
I just want to say that this video is wow 🙀🙀
I am glad you liked my video.
@@EugeneKhutoryansky I am very surprised by your reply sir . And like your million subscribers even I wish to be speaking with you sir (I also know that it wouldn't happen 😅. If that happens means I will reach HD1 galaxy itself sir .And within 272 days I will complete my schooling and I will be free for 3 to 4 months after that.... So due to that (it may sound stupid) can you be my greatest and wonderful and genius physics teacher??
Thank you once again sir for your free high quality videos we students are very much grateful to you..
Consider the first paragraph sir 😄
i love this Channel and i really appreciate all the efforts.
Thanks. I am glad you like my videos.
A very nice and clear explanation of a rather confusing topic (angular momentum). Thanks so much! Ill definitely be passing this video along to my students.
Thanks for the compliment about my video. I hope your students like it.
downloading your all videos.so love form Pakistan.God Bless U
This makes exterior algebra visually obvious. Thank you. Poor ol' Hermann Grassmann was just born too early.
Thanks.
Hello Mr. or Ms. Khutoryansky,
First of all your videos are amazing. Thanks to them i really started to enjoy physics , because now i can visualize the physical concepts and notions much easier and they are nomore boring ,abstract stuff.
I just wanted to ask the following :
Shouldn't the parallelogram in 5:08 and following 20 seconds be a triangle so the angular momentum ( the field of the triangle ) stays constant ?
Thank you very much again.
You'll notice the bottom and top get wider as height decreases. So, area field is still constant, and angular momentum is conserved.
Such a beautiful and thorough explanation!
Thanks. I am glad you liked my explanation.
Thanks.
Best explanation ever found. Keep it coming
Thanks for the compliment.
@@EugeneKhutoryansky thank you, actually. Please make videos more on physics with great animations and everything. Especially about electricity, mechanics and thermodynamics. I know you will deliver the best.
Excellent video as ever!
+saksham chauhan, thanks. Glad you liked it.
Please allow the download button on this video....then I can watch it another few hundred times on my television. Your videos are always high quality due to the clear and concise instructions. Thanks you for putting the time into educating everyone.
Really well done, guys. 👍
Thanks.
This video is amazing, thank you so much
Thanks for the compliment.
Do you intend to make more videos about linear algebra?
+Rodrigo Appendino, yes. I plan to make more videos on linear algebra, in addition to the one that I already have on that topic. Thanks.
+Eugene Khutoryansky YES PLEASE!!! Linear Algebra! :))))
What happens when the distance between the rotaing objects goes to infinity? In that case the areas seems to go to zero. Is angular momentum no longer conserved at infinity?
I love how the music shifted to Blue Danube as angular momentum was discussed...
+Eugene Khutoryansky I love you 😭
I love this channel
Thanks. Glad to hear that.
So why do moons/stars spin backwards creating an angular problem?
I wish i had a teacher like you Eugene
+Premed1981, thanks.
Great video again!
Thanks.
I love your videos.
Great job.
Thanks for the compliment. I am glad you like my videos.
Still couldn't understand. What is angular momentum?
Angular momentum is a measure of the sum total of the cross product of the position vector to, and the linear momentum of each particle in a system, with the position vector taken relative to a common reference point. It is a quantity that is conserved and is used as a method for calculating the effects of interactions among objects within a system, when there are no external torques.
Thanks for the video!
Thanks.
Awesome job !💡
Thanks for the compliment.
I became a fan of yours Eugene! Bravo! You are an awesome person! Greetings from Brazil.
+Eduardo Nogueira, thanks for the compliment, and I am glad to have you as a fan.
very educational, enlightening, intuitive! Wow.!
Thanks. Glad you liked my video.
No doubt great video but for me the background music was too loud and disturbing...
Hi Eugene, could you explain why an object showing the Dzhanibekov effect during rotation is conserving its angular momentum?
I will add the Dzhanibekov effect to my list of topics for future videos. Thanks.
It's ok for momentum explanation . What what is parallelogram and that purple object concept ????🤔🧐
the area of the parallelogram being constant shows that the angular momentum is conserved.
This was amazing!
Thanks. I am glad you liked my video.
Very good explanation and very good voice
Thanks for the compliments.
Thanks for the explanation. I am still confused, however, whether angular momentum and linear momentum are interchangeable. Can you explain more, please?
They are analogous, but not interchangeable. They are both separate quantities of motion that each are conserved in their own right. Linear momentum is defined as the product of velocity and inertia (i.e. mass), as a way to quantify the time-cumulative effect of a force. Angular momentum considers the linear momentum vector and the radius vector from a reference point, as a way to quantify the interactions that would cause rotational motion. Radius cross product linear momentum, is how we define angular momentum.
You can have situations where angular momentum is conserved, while linear momentum isn't, but not vicea. They both are ultimately conserved in the universal sense.
Conservation of linear momentum applies when there are no net external forces acting on the system. Either external forces add up to zero, or aren't present in the first place, or a situation happens so quickly that the external forces can be neglected (like a collision while subject to gravity).
Conservation of angular momentum applies when there are no net external torques acting on a system, relative to the reference point about which angular momentum is defined. So it is OK that there be radial external forces directed parallel to the radius vector when considering conservation of angular momentum, since these forces don't apply a torque to the system. It is the external forces that are not parallel to the radius vector from the reference point, that need to be either excluded or nullified by other external forces, in order for conservation of angular momentum.
So, it's about different point of view... angular momentum requires a well defined center point, right? Thanks for your explanation, @@carultch.
@@benjaminsisko9250 Yes. Angular momentum requires you to assign a reference point, which is usually selected as the point containing the axis of rotation. You will get a different answer if you assign a different reference point. So a problem may specify an origin to use, and in that case you need to use the point specified. Otherwise, you choose the point to assign as the reference point.
It is arbitrary what point you chose to assign, although it is usually the case that one particular point will make the math a lot more convenient, and you'd be "asking for trouble" to pick a different point.
@@carultch The reference point (center point) I pick must be in inertial frame, 'coz if I choose an accelerated frame, then the situation above does not apply, right?
@@benjaminsisko9250 Depends on what kind of accelerated reference frame we are talking about. If the reference frame has a constant linear acceleration, you can use the equivalence principle and treat the apparent inertial force the same way as you would treat any other gravitational field if you were in an inertial reference frame. (Put aside the general relativity meaning of inertial reference frame that requires excluding gravitational fields, and stick to the Galilean/Newtonian meaning of the term, for our purposes).
By contrast, if we are talking about a rotating reference frame, you are much better off looking outside of it, and selecting a point in the inertial reference frame. The Coriolis effect will appear to act as if it is an external torque on any system within a rotating reference frame, which will rule out using conservation of angular momentum unless you also account for the effect.
When the particles repel each other while rotating ,they spin slower to keep the angular momentum constant.
But how do we prove that the angular momentum of the universe is always constant during any interaction?
+Ibrahim Chahrour, this is a consequence of Newton's Laws of motion. Since for every force, there is an equal and opposite force, and F = mA, the net consequence is that momentum and angular momentum must be conserved. We also know this through experiment, in that we have always found momentum and angular momentum to be conserved for every experiment we conducted.
beautifully explained....
thankyou
as far as i know that acceleration is the main factor responsible for the velocities changes but in the video,exactly after the perfectly collision in the situation where 2 objects moved in two different directions, i see that the velocity vectors magnitude have simultaniously changed. So my question is what acceleration have caused the velocities magnitude change like that ?
Acceleration is not a cause. Acceleration is a mathematical description of motion. Acceleration is the effect, when a mass is subject to a net force.
What about momentum and angular momentum of universe???
Why does the direction of angular motion apply to the right hand, not the only hand?
It is just how we chose to define the direction of the angular momentum vector. This is just a social convention, not a law of physics. If we chose to define it the other way, all the observable data would still be the same.
ちょうど学校で習ってたのでありがとう😭
Hello Eugene, I'm confused by the first statement. Did you ignore Noether's theorem? Since energy is not conserved according to general relativity.
Whether energy is conserved in General Relativity is still up for debate. In any case, you can view this as a video just about classical physics.
Everything is always explained so well. Thank you
"Linear momentum is also conserved, since we started out with a linear momentum of zero and ended up with a linear momentum of zero." ~deeply refers to "us" idly sitting, watching this video out of boredom.
How can the area of the parallelogram can be constant for all angles? Area is maximum at 90 degrees and reduces when angle changes.
The area of the parallelogram does not change because the lengths of the base and the height does not change. Details about the area of a parallelogram are in the following link. en.wikipedia.org/wiki/Parallelogram#Area_formula
@@EugeneKhutoryansky Starting from 4.49 height changes. It has max area at 90 when it becomes rectangle and again decreases.
The height is not changing. You may want to look at the picture on the right in the link I provided for the definition of "height."
How do these objects behave in "The real universe"? How does gravity and the ether effect the motions?
Thank u thank u thank u, i’ve learned and understand more of ur 20min videos than years of school😍❤️
In the last described image( two rotating particle),the total angular momentum of the rotation is 2* area of the two parallelogram.but how it the same before and after the rotation?why It is not zero?
It was always rotating, just at different speeds. Therefore, the angular momentum was never zero.
such a wonderful videos , thank you .
+Abduzayir Abdukadir, thanks. I am glad that you like my videos.
your videos are wonderful.
Thanks for the compliment. I am glad you like them.
What is momentum. Yes I get the calculations and all that suff but never understood what it really means? What is momentum and why is it important?
One way to define inertia is mass's tendency to keep an individual object's linear (and angular) momentum. Linear momentum can be said to be the required quantity that requires an external force and some time in order to "destroy" it or increase it.
@@mangaka08 What is the difference between momentum and kinetic energy?
@@mangaka08 I am totally satisfied with your explanation. Thanks . Just wanted know Can we call Momentum rate of motion ? or work done? or type of energy? or force?
@@LinuxLuddite For one thing, momentum is a vector quantity and kinetic energy is a scalar quantity.
@@LinuxLuddite Kinetic energy is significantly more sensitive to velocity than it is to mass. KE also ignores the direction of velocity, because squaring velocity is a self dot product that eliminates the direction. Momentum is equally sensitive to both terms, and maintains the same direction as the direction of velocity.
Start with mass, i.e. inertia.
Integrate with respect to velocity from rest once, and you get momentum.
Integrate with respect to velocity from rest a second time, and you get kinetic energy.
This is where the 1/2 comes from in the kinetic energy formula.
How does universe angular momentum stay constant, if momentum itself doesn't conserve in damped systems (with friction)?
We need to take into account the momentum and angular momentum of all the subatomic particles in the material providing the friction, and then we see that the momentum and angular momentum is still conserved.
verry nice ma'am..
So simple, and so beautifully explained.
+XxKINGatLIFExX, thanks for the compliment.
Physics Videos by Eugene Khutoryansky Np, keep up the good work. Have you got any vids on Quantum Mechanics and Space?
Thanks.
+XxKINGatLIFExX, yes I have many videos on those topics. Just check out my TH-cam home page.
Will do thanks!
Thankyou so much, Your videos are literally awesome 🙌🏻✨
Thanks for the compliment. I am glad you like my videos.
Tq for this vid can u plz tell which software u use or how u make such informative vid plz
I make my 3D animations with "Poser."
eugene, love your work and thank you
question -- if we have two objects attracted by gravity, what is the equal and opposite force of that attraction?
+John Lux, thanks for the compliment. In reply to your question, when the Sun exerts a gravitational attraction on the Earth, the Earth exerts a gravitational attraction on the Sun. I show an animation of this in my "Laws of Motion" video. Thanks.
You're one of the best teachers I've had in physics, but somethings been boggling my mind for a while and this video is a perfect opportunity to ask. Could you please explain how the smaller object when colliding with the bigger one(2.25) does not stop. I know in real life it would bounce off but according to Newton's laws of motion it shouldn't.
According to Newton's third law, there should be an equal and opposite reactionary force on the smaller ball when it applies a force on the bigger ball and since force is equal to the change of momentum, when the bigger ball applies the equal and opposite force, the smaller ball should stop as the force it exerts is equal to it's momentum. This doesn't happen in real life.
Something that may help you that I've thought of, is from a different example. Consider the smaller ball now stationary, and the bigger ball is moving toward it at a constant velocity. Same situation but the roles switched. When the bigger ball hits the smaller ball, I used to think the bigger ball should stop as the smaller ball produces an equal and opposite force to stop it. But then I realised that the bigger ball does not have to exert its full momentum onto the smaller ball, but only enough so that the move at a similar speed. So the momentum of the larger ball only decreases by a smaller amount as it takes less force to get the smaller ball moving at the same speed. That's my reasoning, unfortunately it does not explain what I mentioned earlier. My reasoning lead me to think that the smaller ball has to exert a larger force than its momentum can give to the larger ball, but it then gets cancelled out when the larger ball exerting the same amount of extra force to the smaller ball making it move in the opposite direction.
However the reasoning mentioned in the last paragraph alludes to there being a conservation of velocity which definitely sounds untrue. I hope you read and understand my long winded messy post and give some kind of solution based on what you can understand of what I am saying, I hope I'm not wasting your time, sorry :)
Meeharbi N the reaction is the one object stopping. the force brings the object to zero so there still is a equal and opposite force but it's just the perfect amount to stop it and not have the ball move in another direction
Meeharbi N it depends also on how elastic the collision is and if energy is lost in the collision. it does happen all the time so you saying it doesn't is simply wrong
You are understanding is incorrect.
Please to refer to F=ma .
let m1 be the smaller ball and m2 be the bigger ball and also let's assume
m1= 1kg and m2= 10kg .
then after collision between the balls it is abvious the smaller ball will bounce back with greater acceleration that the bigger ball.
In this case, by the equation f=ma , we can safely say that it's acceleration (lets assume m1 acceleration be a1 and m2 acceleration be a2) wil be in the ratio 10:1 so as to show f=m1.a1 = m2.a2.
Beautiful!
Thanks.
Track ID?
All the music in this video is from the free TH-cam audio library, and the names of the songs are the following.
Moonlight_Sonata_by_Beethoven
Road_to_Moscow
Blue_Danube_by_Strauss
@@EugeneKhutoryansky Thank you very much and nice video by the way! It helped for my last Physics test
5:50 why?
The short answer is, it's just a convention.
The long answer is, that we opt to define angular quantities perpendicular to the plane of rotation, to eliminate the number of arbitrary options we have to choose. We choose the axis of rotation instead of the plane of rotation, so that 360 degrees worth of arbitrary options turn into just two arbitrary options. We chose the right-handed option, for consistency with the way the majority of threaded fasteners work: "righty tighty/lefty loosey".
Thank you very much for this video!
I have a question, is there a way to know why the angular momentum is at 90°? (Momentum that is apparently to the right of the object, assuming that the direction to which the object moves is the "front").
Edit: I have no idea, but if I had to guess, I'd say it's like the "residual force" from the axis, which would make the orbits to slowly lose force.
This is just the way we chose to define the term "angular momentum." This definition happens to be useful for calculations. Thanks.
Thank you very much for this high quality content. You have a really good manner to explain this theoretical concept very easily.
I read about moment of momentum before. I had understood the mathematics behind this object. But I could not figure out correctly how to physically represent it in real life, and the consequences of this concept. For instance, the increasing or decreasing velocity with the opposite decreasing or increasing of rotation radius. With your video is definitely very clear.
There is so many other subjects you could represent and explain like this.
Thank for the compliments about my video. I have many other videos on my channel in which I explain other subjects in this manner. Thanks.
Thank you so much. Amazing explanation.
Thanks. I am glad you liked my video.
Plz make a vedieo for friction , rotation motion.
I have a video on rotation titled "Torque, Levers, and the Universal Law of Rotation" at th-cam.com/video/leZX0GpV5W0/w-d-xo.html
Yes. An amazing presentation. Very informative.
Thanks. I am glad you liked my video.
Why does angular momentum point 90deg relative to the planes toward the observer in clockwise rotations and 90deg away from the observer in counterclockwise rotations? I never got that, why that particular direction?
+Raymond Fernandez, actually, it is the reverse, but in reply to your question, this is just an arbitrary convention. We could have just as easily defined it the opposite way, so long as we also defined the direction for the torque arrow in the same way.
The reason why we opted to assign the direction of angular quantities to be along the axis, is to reduce the number of arbitrary options we had to choose. It is more a matter of bookkeeping and convention than anything physical actually happening in that direction.
If we opted for a direction in the plane of rotation, we'd have 360 degrees worth of options to choose from, which is an infinite continuum that gets us nowhere. By choosing the axis of rotation, we now have only two options from which to choose. We either get to define it so CCW is toward the observer, or CW is toward the observer. We opted for CCW being defined toward the observer, for consistency with how the majority of threaded fasteners work and we use right-handed coordinate systems to be consistent.
why is the electric charge always the same? what if pro- and electrons melt as in neutron stars? happy for any response ;D
+Naratuga T, an electron has a negative charge, and a positron has a positive charge. The sum of the charge of an electron and a positron is therefore zero. If these two particles annihilate each other, the total net charge is zero both before and after the reaction.
beautiful explaination. thanks a ton
Glad you liked my explanation. Thanks.
Angular momentum is quantum, and is known in the quantum world as "spin." Bosons have a integer spin, and fermions have a half-integer spin.
Why did we define the standard such that fermions have half-integer spin? Why not just cut the reference spin value in half, and give fermions a spin number of 1, and bosons a spin number of even integers?
I'm not trying to ask rhetorically, I really would like to know what was behind setting up the standard for spin numbers in quantum mechanics, that caused half-integer spins to exist.
In the linear momentum example I get shocked: vectors addition leads to incoming small ball crashing with a big green one happening ā = -ā + 2*ā , the small gets away from it were coming and the other have "twice more momentum than the original"!!... so, What will happen if the green one crashed another small one in chain giving all its moment? It will result in an overall momentum of and incoming ball with momentum ā which ends in a exactly alike ball traveling with momentum 2*ā !!, which is impossible from conservation of energy!!... so my question is: Is really possible to have this ā = -ā + 2*ā collision??? My intuition says from energy conservation also must happen that (incoming momentum)^2 = (final momentum)^2, so this example leads to a^2 = a^2 + 4*a^2 which is obviously wrong, so I think that actually the scenario is impossible (if my assumption is right).
Also about the parallelogram example refered to an arbitrary point: since the velocity is constant and the radii of the another vector changes more than the cosine of the angle, I believe that the area is not constant.. if the ball have travel to infinity far away the area will certainly be infinite, differently if the vector is rotating towards the point were the parallelogram is always the same. Also if something is not rotating, I believe its angular momentum is zero, so the linearly travelling ball refered to an arbitrary point is not a good example.
Excellent explanation
I am glad you liked my explanation. Thanks for the compliment.
Can this help my golf swing?
How is this arbitrary point related to these two particles? Didn't understand that part. Do they exert force on this point?
+Max Webster, it is any point that we pick in space. No, this point does not exert a force on the particle. It is just that for any point we pick in space, the angular momentum around that point, as described here, will remain constant.
which software did you use to do this 3d animations?. ...
+aadarsha subedi, I make my 3D animations with "Poser."
+Eugene Khutoryansky Thanks a lot for the information. ..
The first thing I don't understand is that the total amount of electric charge in the universe is always constant. When I charge a capacitor, and then connect it to a heating coil, it discharges and converts the electric charge into heat. So where did the electric charge go, since it was converted into molecular movement (=heat) in the heating coil?
+Seegal Galguntijak, when a capacitor discharges, the excess electrons on the negative plate simply move to the positive plate. As they do this, they collide with other atoms, and their energy of motion is converted into heat.
Eugene Khutoryansky I see - never thought of that. Of course the amount of charged particles in a capacitor itself is always the same, whether it is in a charged or discharged state.
can you tell me what software packages do you use to make the videos??
I make my 3D animations with "Poser."