I remember my high school physics teacher did the rotating chair angular momentum demo on the table top - he climbed up and began the spin - when he pulled his arms and legs in the spin increased so much he flew off the table and cleaned up the first row of students seated in the class room and inadvertently demonstrated all of the Newton's 3 laws of motion
Actually It's the caster effect that keeps the bike going straight. The caster effect causes the bike to move in the direction the front wheel is facing. The gyroscopic force keeps it from tipping over, which is why it's much easier to stay upright on a bike when moving quickly. If what your saying is true, and it is all about balance rather than gyroscopic force, it should be just as easy to balance on a bike that is still. In actuality it is much more difficult.
Every time I have the chance to play with this principle of Physics I fell like a kid. Amazing how we can apply Physics in our daily lives. Wonderful comments. Thank you for such comprehensive video. 🏆
Angular momentum helps at high speed on bicycles but on mini wheel scooters at normal speed it can't really help. What does help is our very fast steering response. If a bike starts to fall to the left we learn to steer towards the left at the same time. Steering left without leaning left actually provides a net force to the right. If you don't believe this, try turning left without leaning and you will fall to the right. Its also why we have to lean left to turn left, if we don't we fall off.
@DoomCreeper1: Glad to have you onboard... You might also like periodicvideos, our channel about chemistry! And nottinghamscience has all the behind the scenes stuff and other bits of science.
As an old Breakdancer I remember how light my body got during headspins, 1990's,handspins, backspins and coasters.. also realizing central fugal force plays a big part of making the body feel lighter whilst in motion.. also I have rid bikes for years and yes they are lighter whilst moving.. no handed and downhill is easier to control than standing on peddles and balancing with brakes on.. maybe the central fugal force of the wheels help keep it balanced as you can feel that force for yoursels try it.. I know it has more force on the vertical &horizontal, yet diagonally it just wants to go horizontal or vertical which ever is nearest at the time.. ( :
@Koroistro it "acquires" angular momentum to keep the total momentum the same if the wheel is spinning clockwise then he has to spin counterclockwise to keep that angular momentum constant I think this is one of the hardest concepts to understand in classical mechanics... try to think of it the same way as in linear momentum
I'm not sure why prof. said angular momentum equals m times r^2, because the formula I know contains mass, velocity and radius. So if you take this (L=m*v*r) you can see that if radius gets smaller speed needs to get higher in order to conserve angular momentum.
ice skaters and other dancers reduce dizziness by turning their head and eyes to look at a single point for as long as possible, then quickly turning the rest of the way before repeating
@dwip57 im sure that precession is the slow movement that the wheel exhibits on its side while angular momentum is the momentum that the rotating object carries
Dancers avoid getting giddy by a technique called "spotting". Simply, choose a fixed spot to look at. Keep your head and eyes looking at that spot for as long as possible, whilst spinning. Of course, at a certain point, you'll spin too far around to be able to keep the spot in sight. So you, as quickly as possible, spin your head back around to be able to see the spot once more. As you're "spotting", you're delaying the moment when you've got to look away as much as possible and then rapidly spin back to looking at the spot again as quickly as possible. So you can see that, by this technique, the dancers are - at least with their heads, but that's the bit that matters for one's sense of balance - minimising their spin as much as possible. (By the way, this same technique does actually work on rollercoasters too. I tried it once on a particularly hairy ride, when not feeling 100%, and it totally got me through.)
Just scrolling through my youtube and thought I recognized this chap. Professor Bowley took us for thermodynamics and statistical mechanics in Nottingham, several years ago now.
Just in case I got part of your question better than FoValentine (whose answer was great): the Earth does not perform work on it's satelites to keep them in orbit. Objects in any orbit stay that way without any input of energy. This way, having satelites do not, not even in theoretical terms, slows Earth's rotaion. However, it is true that there is momentum transfer from Earth (which is slowing down) to the Moon (which is receding), but for another reason.
I thought bikes worked also on a different principle, as well as angular momentum - When you lean over when you're standing stationary, you'll fall over. But if you're running and you lean over (and note that when you're running, not cycling, nothing is rotating) you move forward into that direction, which corrects your angle.
There's a motorcycle whose engine has two crankshafts which spin in opposite directions. The purpose of this is to have one spinning mass cancel out the angular momentum of the other and thus making the motorcycle easier to lean into turns.
I totally agree with Prof. Bowley, I do this demonstration in my physics class, but I always wait for the end of the period because I feel so sick and ill when I do it I cannot go on teaching. Luckily, physics is my last class of the day. No clue how ice skaters pull off not getting dizzy.
This is the technology of the future which many propulsion systems will be based on. I did extensive research into this years ago. There are no equations yet for these actions and properties. Some scientists studying this became so fascinated, they stayed up many days straight and had a nervous breakdown, which then makes other scientists less likely to want to study it. Maybe when they understand what a nervous breakdown is and how to avoid it, we will see this new technology developed. :)
The first time we see the videos is when they appear on UA-cam--- we do not have the chance to edit them. After amaking several videos we learn to trust Brady to make our efforts into interesting and informative videos without making us look ridiculous.
I did this when I was three because it was fun as hell, now at 21 and working on my degree, I spin around in my chair because it's fun as hell AND I understand why!
@itstheMAC Angular momentum is only conserved of there is no torque acting on the system; the wheel roitates because the tension in the string gives a force on the axle at a point which is away from the centre of mass of the wheel. Hence there is a torque and the axle of the wheel rotates, changing the direction of the angular momentum. The direction of a torque is given by a vector product; I was unable to persuade Brady that it was a suitable symbol for sixty symbols: too mathematical!
Thank you to Brady and all the professors featured over the years. These videos are like the light at the end of the tunnel. Motivation to keep slogging through classes like calc, general physics, etc. One day I'll be learning cool things like this :)
@PartVIII Videos of physics demonstrations (without the relevant mathematics) can engage the viewer; they can show that there are funny effects in the real world; and they give me the chance to give a physical explanation. Of course to do the job properly you need to expresses your ideas mathematically in order make rigourous predictions of what should be seen experimentally: that is the basis of the scientific method. Brady prefers me (a theoretical physicist) to do experiments badly.
@Gytax0 Sure, the theory is alright. It's just the scale and significance ascribe to it when it comes to balancing a bicycle is way off. It's kinda like the people who say the direction water turns when it runs down a drain can be explained by the Coriolis effect. Sure, it does have a tiny tiny effect, but it is by no means the determining factor.
Yes, this would be true, however, considering the mass of the earth and the mass of the space elevator, the effect this would have would be negligible. Also, this shouldn't effect our satellites(other than that some would have to be re positioned) as their orbits are independent from the earths rotation. Interestingly enough, the tidal relationship between the earth and the moon allow this principle to apply to the moon (it is receding from earth in case you didn't know)
I agree to the fact that when one is riding bike without having hands on handle, gyroscopic forces prevent the fork from turning. But, balancing the bike itself won't become any easier due to gyroscopic effect. If at all gyroscopic forces keep the bike upright, why would anyone spend so much of time in learning to ride bikes? It is because one is actually learning the art of balancing.
So I looked up the Wikipedia article called "Bicycle and motorcycle dynamics" and it says gyroscopic effects, like the ones shown in this video, are actually only a very minor contributer to the ability to balance a bicycle. It could almost be said that it is somewhat of a common misconception among physics instructors that gyroscopic effects play a large role in balancing a bicycle.
No matter how many times I see that demo (the one at 2:40), or look at the vectors and convince myself that it should behave in that way, it still seems like magic. Gyroscopes are just not intuitive in any way...
How ice dancers and ballerinas usually do to help keep themselves from getting dizzy is they hold their head stationary in relation to the ground as long as possible, then quickly whip it around. With this start-stop method of turning, the fluids in your ear are shaken instead of being slowly pulled to the outside, making you dizzy. Of course, if you do it long enough, I'm sure the net force would eventually make you dizzy, but for the short bursts they do, it is negligible.
spontanuius random thought have a craft genarate a field around itself in a specific diameter designed to push out all molcues of resistance to create a sphere in which perpetual motion could b achived to have the craft generate is own limitless energy and move anywhere cause the field can b moved any where
@MrOldprof The mathematics is what makes physics so elegant! Youre not asking the viewers to solve any problems, but having a simple explanation of the mathematical background helps put somewhat abstract concepts into perspective. Mathematics gives shape to the interlocking puzzle pieces of the physical properties of nature. Mathematics helps us understand the whole picture. Physics videos without mathematical expressions is like Chemistry videos without molecular structures.
The ice skaters have trick (borrowed from ballet dancers, I think): They often don't let their head spin with the rest of the body. They keep the direction of the nose constant for as much of the time as possible, which is most of the time. And when it isn't possible, they quickly spin the head around much quicker than the body, until the nose has resumed it's former direction. But I think even with this trick it takes some getting used to.
That is very cool, i would never have thought that the momentum from a wheel could do things like that, i only thought that it spun and was nothing special! cool!
Does high current goes through a loop also create angular momentum? If that is the case, magnet should have angular momentum too, right? And can I change a metal object angular momentum by changing the magnetic field?
@metalbucket2 Hmm. I dunno whether this is even the right place to say this, but here goes. Your comment is exactly why I prefer 60S over BigThink. I found both of these channels TONIGHT. They both started off on equal footings, but I just can't stand BT. It's mostly just Michi Okaku talking to hear himself talk; the audience is just there to stroke his ego. But the profs here at 60S seem like they're enthusiastically explaining what they love; there just happens to be someone recording them.
ANGULAR MOMENTUM , WHAT WE'VE JUST WATCHED IS ACTUALLY A KNOWLEDGE KNOWN BY FEW PEOPLE . THESE SCIENTISTS DO A GOOD JOB OF DESCRIBING IT. IF ADAPTED TO NEW WAYS OF CREATING MOVEMENT , OR USED AS A PRIME MOVER, IT SHOULD ALWAYS BE TAKEN INTO CONSIDERATION . GIANFRANCO FRONZI SEPTEMBER
I slow the earth when I stand up from my computer chair. When I sit back down the earth speeds back up. It’s just not that much that we notice. If we started launching mountains in to space, after a while we would notice. Our little satellites don’t have much mass (hence Angular Momentum) compared to the entire earth.
It's impossible to reach, as each successive decimal becomes harder to attain. You can always get closer to the speed of light, so you can always speed up. You can just never reach it. Just as you can always add +1 to a number, but you can never reach infinity. There's really a vast difference between 99% of the speed of light and 99.99% the speed of light, a lot more than 1% increase in energy required, mass gained and relativistic effects like time dilation.
I'm shocked as I've watch so many of these videos by Professor Bowley and they are absolutely brilliant, but I cannot believe that he's got the theory of why bicycles remain up right, so wrong. Angular momentum has hardly any effect on keeping a bike upright. First the mass of the wheels are not that great compared the human that's sitting on it, and the wheels don't rotate that fast. If it were true, then bikes with smaller wheels would be harder to ride, but they are not. A simple bit of maths will show that the small mass of the wheels would have to rotate a ridicules rate to have any effect over the mass of the human pay load. The reason we stay up right on a bike is because while the bike is moving, if we turn a bit to the left, centrifugal force (which is acting on the bike and the human as a whole) will push us to the right and vice versa. We learn to keep ourselves upright by steering towards the fall. If a bike not moving then steering the wheels will not produce any centrifugal force and hence you fall off. A simple test would be to make a bike that has skids instead of wheels. You will still be able to remain up right as long as you're moving. Then make a bike that has big wheels but where the handle bars are welded straight forward. You will simple fall off this bike immediately.
I am a former Bike Messenger, championship racer, mechanic and owner of a Bike shop. In my opinion, the bike stays upright mostly because it's operated like an inverse pendulum. That is, through tiny adjustments we keep our weight balanced above. The angular momentum does play a factor, and it's especially noticeable when you compare the stability of a bike thats wheels have a high rotational mass, like a mountain bike or a beach cruiser, to a road bike that has race tires and wheels. Oh and don't make the mistake of thinking that this has something to do with the size of the contact patch on the asphalt. The difference is millimetres. Also, MTB tires actually have less contact and therefore grip on a road surface. A common misconception. The same size tire with a much lighter rim is notably more unstable but therefore more maneuverable. It's just inertia at work.
I Must say I have thought about it some more and the angular momentum must have some small effect as it is possible to ride and remain upright (albeit for a small distance) with no hands on the handlebars but impossible to remain upright if you are stationary. But you are still nowhere near as stable as you are when actually steering while moving.
Fully Agree. Naive to assume that bicycles, or people for that matter, manage to stay upright due to gyroscopic effect. Bicycles and Airplanes have interesting and important stability functions which a Physics professor should understand more fully. This is a bit of a FAIL I'm afraid. A Bicycle is self-stabilizing (can stay upright without a rider or ridden with no hands) for two reasons: Wheels are self-righting by their nature, as they naturally turn into any direction of lean; and two, the front wheel touch the ground at a point slightly BEHIND the (imaginary) extension of the headstock axle - which induces the wheel to turn in the direction of any sideways force - (try this: hold a bike upright without touching the handlebars, and force the bike to the left, the front wheel will turn left in response - they better the bike, the more sensitive it will be to this motion.) As another says: replace wheels with a ski, and balance is still achieved. Both a snow ski and water ski will depress until a slight curve exists, and this curve when angled over will result in a corrective turn - tending towards uprightness. The gyroscopic stability of wheels which are as light as possible (unlike in video) is immaterial at slow speeds - and yet bicycles can be ridden at a walking pace. That said, I would think some additional experimentation is in order.
I think he meant without moving the unicycle at all, just using your upper body; probably still possible with a lot of training and the right circumstances, but very difficult. ;-)
It's the Quantum Field Mechanism prime- primarily dominant in the first three phase-states and geometry where the axial-tangential distribution of probability is actively rotating and therefore aligned with a resonance plane tangential to the wheel axle and parallels. Ie of the 3 orthogonal planes, two vertical and one horizontal, the bike and rider have "tuned in" to an inertial probability position, least timing and all that..., and a complete description in the QM-TIME applied principle of the system involving the nature of relative solid and liquid phase-states in 1-0D orthogonality.., is too long for a comment. (?) The Professor has demonstrated what cannot be easily put into words. Applying the Quantum Fields Modulation Mechanism to the situation: if gravity is the name for the "cooling" curvature of QM-Time, (inflation is the "heating"), exponential function, then the phase-states spectrum of spacing-timing interference-probability has Pi-i circulation possibilities of orbital/orbits in the general cause-effect of continuous containment->reflection environment of "One Electron" type superposition singularity vanishing point, distribution image of combined Superspin. So physically rotating an object shifts the tuning of the object's phase-states into the orthogonal-tangential plane, around the Universal zero point axis-vanishing point, the 1-0D prime-timespace dimension and sum-of-all-history now. "You're supposed to work it out for yourself ", Monty Python. Don't just hang around?
Bowley is completely right. A mountain bikers philosophy is the faster you go the safer you are. People look at you like you are crazy, but PHYSICS PROVES IT!
One thing that confuses me is why angular momentum/velocity/torque is depicted as perpendicular to the axis (right hand rule). Is there actually any force acting in that direction or is it just depicted that way to "help" show how angular momentum is conserved? I'm assuming it's the latter but I'd love clarification on this.
Wait... Would the theoretical space elevator slow the Earth day, similar to how the distribution of mass affects the speed of rotation? Further more, If the speed does decrease, then what is the difference between that and geo-stationary satalites, or even the regular satalites?
sacrifices were made in the name of physics
I’m going to hijack this top comment just to give a shout-out to George!
I remember my high school physics teacher did the rotating chair angular momentum demo on the table top - he climbed up and began the spin - when he pulled his arms and legs in the spin increased so much he flew off the table and cleaned up the first row of students seated in the class room and inadvertently demonstrated all of the Newton's 3 laws of motion
Professor Bowley is a wonderful mix of intelligent, endearing and respectable.
And joy 😊
One day George will snap !
Monocycle and ice dancers.
Where would we be without George?
Courtney Smith .... seriously, George does all the work!
What a gem of a video! Thanks prof. Miss you in the newer videos.
Silent George is the unsung hero of these 60 Symbols videos!
Spin Doctor
best physics channel. easy to understand, with a dollop of fun
Actually It's the caster effect that keeps the bike going straight. The caster effect causes the bike to move in the direction the front wheel is facing. The gyroscopic force keeps it from tipping over, which is why it's much easier to stay upright on a bike when moving quickly. If what your saying is true, and it is all about balance rather than gyroscopic force, it should be just as easy to balance on a bike that is still. In actuality it is much more difficult.
Great demonstration of how reaction wheels work to control the orientation of satellites.
BTW Brady, you are an absolute star for making all these and walking the line between informal unscripted chat and purely educational videos.
The professor is just so English
Every time I have the chance to play with this principle of Physics I fell like a kid. Amazing how we can apply Physics in our daily lives. Wonderful comments. Thank you for such comprehensive video. 🏆
Angular momentum helps at high speed on bicycles but on mini wheel scooters at normal speed it can't really help.
What does help is our very fast steering response. If a bike starts to fall to the left we learn to steer towards the left at the same time. Steering left without leaning left actually provides a net force to the right. If you don't believe this, try turning left without leaning and you will fall to the right. Its also why we have to lean left to turn left, if we don't we fall off.
@avecesdeunhilo: Thanks... Always prefer having typos pointed out in things I can actually fix, rather than finished videos! :)
This channel is a dream come true for Geeks and nerds.
@DoomCreeper1: Glad to have you onboard...
You might also like periodicvideos, our channel about chemistry!
And nottinghamscience has all the behind the scenes stuff and other bits of science.
As an old Breakdancer I remember how light my body got during headspins, 1990's,handspins, backspins and coasters.. also realizing central fugal force plays a big part of making the body feel lighter whilst in motion.. also I have rid bikes for years and yes they are lighter whilst moving.. no handed and downhill is easier to control than standing on peddles and balancing with brakes on.. maybe the central fugal force of the wheels help keep it balanced as you can feel that force for yoursels try it.. I know it has more force on the vertical &horizontal, yet diagonally it just wants to go horizontal or vertical which ever is nearest at the time.. ( :
lol centrifugal ( :
The videos on sixtysymbols are all filmed and edited by me (Brady) and feature various experts from the University of Nottingham.
thanks, your videos are a real treasure
@Koroistro it "acquires" angular momentum to keep the total momentum the same
if the wheel is spinning clockwise then he has to spin counterclockwise to keep that angular momentum constant
I think this is one of the hardest concepts to understand in classical mechanics...
try to think of it the same way as in linear momentum
I enjoyed this one. it's one of my favorite subjects to think about in my spare time.
I'm not sure why prof. said angular momentum equals m times r^2, because the formula I know contains mass, velocity and radius. So if you take this (L=m*v*r) you can see that if radius gets smaller speed needs to get higher in order to conserve angular momentum.
ice skaters and other dancers reduce dizziness by turning their head and eyes to look at a single point for as long as possible, then quickly turning the rest of the way before repeating
@dwip57 im sure that precession is the slow movement that the wheel exhibits on its side while angular momentum is the momentum that the rotating object carries
Dancers avoid getting giddy by a technique called "spotting".
Simply, choose a fixed spot to look at.
Keep your head and eyes looking at that spot for as long as possible, whilst spinning.
Of course, at a certain point, you'll spin too far around to be able to keep the spot in sight. So you, as quickly as possible, spin your head back around to be able to see the spot once more.
As you're "spotting", you're delaying the moment when you've got to look away as much as possible and then rapidly spin back to looking at the spot again as quickly as possible. So you can see that, by this technique, the dancers are - at least with their heads, but that's the bit that matters for one's sense of balance - minimising their spin as much as possible.
(By the way, this same technique does actually work on rollercoasters too. I tried it once on a particularly hairy ride, when not feeling 100%, and it totally got me through.)
Just scrolling through my youtube and thought I recognized this chap. Professor Bowley took us for thermodynamics and statistical mechanics in Nottingham, several years ago now.
@chrisofnottingham
thank you.... I'm lucky to have so many clever scientists at my disposal!!!
Just in case I got part of your question better than FoValentine (whose answer was great): the Earth does not perform work on it's satelites to keep them in orbit. Objects in any orbit stay that way without any input of energy. This way, having satelites do not, not even in theoretical terms, slows Earth's rotaion. However, it is true that there is momentum transfer from Earth (which is slowing down) to the Moon (which is receding), but for another reason.
I thought bikes worked also on a different principle, as well as angular momentum -
When you lean over when you're standing stationary, you'll fall over. But if you're running and you lean over (and note that when you're running, not cycling, nothing is rotating) you move forward into that direction, which corrects your angle.
i hate to pick favorites but if i had to choose, Professor Bowley takes the cake.
I love science for teachers like this!
Very cool and amazing explanation of the angular momentum, especially the litte 'experiments' done are fascinating !
There's a motorcycle whose engine has two crankshafts which spin in opposite directions. The purpose of this is to have one spinning mass cancel out the angular momentum of the other and thus making the motorcycle easier to lean into turns.
I totally agree with Prof. Bowley, I do this demonstration in my physics class, but I always wait for the end of the period because I feel so sick and ill when I do it I cannot go on teaching. Luckily, physics is my last class of the day.
No clue how ice skaters pull off not getting dizzy.
This is the technology of the future which many propulsion systems will be based on. I did extensive research into this years ago.
There are no equations yet for these actions and properties. Some scientists studying this became so fascinated, they stayed up many days straight and had a nervous breakdown, which then makes other scientists less likely to want to study it. Maybe when they understand what a nervous breakdown is and how to avoid it, we will see this new technology developed. :)
Professor Bowley reminds me of my first physics teacher, who once lost control of the projectile during a projectile motion demonstration.
5:58 "what is a professor when he spins?" The man had made a question. Answer him!
a rotating scholar field? i'll see myself out ;>_>
Profeller! 😂
A cat.
a poll dancer
This is so great.
This video blew my mind. With the floating globe and the spinning chair...
Something tells me that this place would be total chaos without George.
The first time we see the videos is when they appear on UA-cam--- we do not have the chance to edit them. After amaking several videos we learn to trust Brady to make our efforts into interesting and informative videos without making us look ridiculous.
George looks older than Bob Bowley and about 1/10 the weight. It made me chuckle when he asked George to spin him on the turn table.
This feels so counterintuitive.
I agree
+Campbell Hutcheson Look at "gyroscopic precession and gyroscopes" by eugene kutoryansky, a fantastic youtube channel.
And yet we have not applied this to the wheel. A phenomenal break through bringing us closer to gyroscopical transportation
I did this when I was three because it was fun as hell, now at 21 and working on my degree, I spin around in my chair because it's fun as hell AND I understand why!
@SimaanFreeloader It still helps in theory. Try tilting a spinning bicycle wheel. You'll find it much harder than if it wasn't spinning.
best bit of the open day there,
spending ten minutes getting that globe to float
@itstheMAC Angular momentum is only conserved of there is no torque acting on the system; the wheel roitates because the tension in the string gives a force on the axle at a point which is away from the centre of mass of the wheel. Hence there is a torque and the axle of the wheel rotates, changing the direction of the angular momentum.
The direction of a torque is given by a vector product; I was unable to persuade Brady that it was a suitable symbol for sixty symbols: too mathematical!
they are at the University of Nothingham in England
Thank you to Brady and all the professors featured over the years. These videos are like the light at the end of the tunnel. Motivation to keep slogging through classes like calc, general physics, etc. One day I'll be learning cool things like this :)
@PartVIII Videos of physics demonstrations (without the relevant mathematics) can engage the viewer; they can show that there are funny effects in the real world; and they give me the chance to give a physical explanation. Of course to do the job properly you need to expresses your ideas mathematically in order make rigourous predictions of what should be seen experimentally: that is the basis of the scientific method. Brady prefers me (a theoretical physicist) to do experiments badly.
As a unicyclist, I can proudly say that it is not impossible to balance a stationary unicycle or monocycle.
I want to be able to see these forces, it is so freaky that such a simple demonstration is beyond normal perception.
@Gytax0 Sure, the theory is alright. It's just the scale and significance ascribe to it when it comes to balancing a bicycle is way off. It's kinda like the people who say the direction water turns when it runs down a drain can be explained by the Coriolis effect. Sure, it does have a tiny tiny effect, but it is by no means the determining factor.
Yes, this would be true, however, considering the mass of the earth and the mass of the space elevator, the effect this would have would be negligible. Also, this shouldn't effect our satellites(other than that some would have to be re positioned) as their orbits are independent from the earths rotation.
Interestingly enough, the tidal relationship between the earth and the moon allow this principle to apply to the moon (it is receding from earth in case you didn't know)
I agree to the fact that when one is riding bike without having hands on handle, gyroscopic forces prevent the fork from turning.
But, balancing the bike itself won't become any easier due to gyroscopic effect. If at all gyroscopic forces keep the bike upright, why would anyone spend so much of time in learning to ride bikes? It is because one is actually learning the art of balancing.
So I looked up the Wikipedia article called "Bicycle and motorcycle dynamics" and it says gyroscopic effects, like the ones shown in this video, are actually only a very minor contributer to the ability to balance a bicycle. It could almost be said that it is somewhat of a common misconception among physics instructors that gyroscopic effects play a large role in balancing a bicycle.
No matter how many times I see that demo (the one at 2:40), or look at the vectors and convince myself that it should behave in that way, it still seems like magic. Gyroscopes are just not intuitive in any way...
How ice dancers and ballerinas usually do to help keep themselves from getting dizzy is they hold their head stationary in relation to the ground as long as possible, then quickly whip it around. With this start-stop method of turning, the fluids in your ear are shaken instead of being slowly pulled to the outside, making you dizzy. Of course, if you do it long enough, I'm sure the net force would eventually make you dizzy, but for the short bursts they do, it is negligible.
spontanuius random thought
have a craft genarate a field around itself in a specific diameter designed to push out all molcues of resistance to create a sphere in which perpetual motion could b achived to have the craft generate is own limitless energy and move anywhere cause the field can b moved any where
I always had a problem understanding angular momentum, but this is a very good explanation.
Your chair is breathtaking
@MrOldprof The mathematics is what makes physics so elegant!
Youre not asking the viewers to solve any problems, but having a simple explanation of the mathematical background helps put somewhat abstract concepts into perspective. Mathematics gives shape to the interlocking puzzle pieces of the physical properties of nature. Mathematics helps us understand the whole picture.
Physics videos without mathematical expressions is like Chemistry videos without molecular structures.
@RookieStudios: I'll see if I can talk George into it...
The ice skaters have trick (borrowed from ballet dancers, I think): They often don't let their head spin with the rest of the body. They keep the direction of the nose constant for as much of the time as possible, which is most of the time. And when it isn't possible, they quickly spin the head around much quicker than the body, until the nose has resumed it's former direction.
But I think even with this trick it takes some getting used to.
this is called Spotting.
That is very cool, i would never have thought that the momentum from a wheel could do things like that, i only thought that it spun and was nothing special! cool!
im so glad someone made the spin doctor joke before me
I love this YT video
Now I understand the term "spin doctor"
But using angular momentum you can orientate and keep the monocycle at ANY direction, not just the vertical one as you are probably refering to.
Professor Bowley is so cool!
Does high current goes through a loop also create angular momentum?
If that is the case, magnet should have angular momentum too, right?
And can I change a metal object angular momentum by changing the magnetic field?
@metalbucket2 Hmm. I dunno whether this is even the right place to say this, but here goes.
Your comment is exactly why I prefer 60S over BigThink. I found both of these channels TONIGHT. They both started off on equal footings, but I just can't stand BT. It's mostly just Michi Okaku talking to hear himself talk; the audience is just there to stroke his ego. But the profs here at 60S seem like they're enthusiastically explaining what they love; there just happens to be someone recording them.
what makes the wheel stay in vertical position while rotating around the string? why it does not fall?
profesor got sense of humor, nice!
Thank you very much for the content
4:42 And i could keep.. That is FUN.. keep turning it over.
Just love this professor :D
i want a professor like you!
ANGULAR MOMENTUM , WHAT WE'VE JUST WATCHED IS ACTUALLY A KNOWLEDGE KNOWN BY FEW PEOPLE . THESE SCIENTISTS DO A GOOD JOB OF DESCRIBING IT. IF ADAPTED TO NEW WAYS OF CREATING MOVEMENT , OR USED AS A PRIME MOVER, IT SHOULD ALWAYS BE TAKEN INTO CONSIDERATION .
GIANFRANCO FRONZI SEPTEMBER
I would have appreciated studding under that kind of passionate lecturer and probably would have done much better in physics. My best regards.
I slow the earth when I stand up from my computer chair. When I sit back down the earth speeds back up. It’s just not that much that we notice. If we started launching mountains in to space, after a while we would notice. Our little satellites don’t have much mass (hence Angular Momentum) compared to the entire earth.
It's impossible to reach, as each successive decimal becomes harder to attain. You can always get closer to the speed of light, so you can always speed up. You can just never reach it. Just as you can always add +1 to a number, but you can never reach infinity. There's really a vast difference between 99% of the speed of light and 99.99% the speed of light, a lot more than 1% increase in energy required, mass gained and relativistic effects like time dilation.
I'm shocked as I've watch so many of these videos by Professor Bowley and they are absolutely brilliant, but I cannot believe that he's got the theory of why bicycles remain up right, so wrong. Angular momentum has hardly any effect on keeping a bike upright. First the mass of the wheels are not that great compared the human that's sitting on it, and the wheels don't rotate that fast. If it were true, then bikes with smaller wheels would be harder to ride, but they are not. A simple bit of maths will show that the small mass of the wheels would have to rotate a ridicules rate to have any effect over the mass of the human pay load. The reason we stay up right on a bike is because while the bike is moving, if we turn a bit to the left, centrifugal force (which is acting on the bike and the human as a whole) will push us to the right and vice versa. We learn to keep ourselves upright by steering towards the fall. If a bike not moving then steering the wheels will not produce any centrifugal force and hence you fall off. A simple test would be to make a bike that has skids instead of wheels. You will still be able to remain up right as long as you're moving. Then make a bike that has big wheels but where the handle bars are welded straight forward. You will simple fall off this bike immediately.
+Pete Johnston He said ONE of the reasons not the reason classic case of the "telephone" game.
I am a former Bike Messenger, championship racer, mechanic and owner of a Bike shop. In my opinion, the bike stays upright mostly because it's operated like an inverse pendulum. That is, through tiny adjustments we keep our weight balanced above. The angular momentum does play a factor, and it's especially noticeable when you compare the stability of a bike thats wheels have a high rotational mass, like a mountain bike or a beach cruiser, to a road bike that has race tires and wheels. Oh and don't make the mistake of thinking that this has something to do with the size of the contact patch on the asphalt. The difference is millimetres. Also, MTB tires actually have less contact and therefore grip on a road surface. A common misconception.
The same size tire with a much lighter rim is notably more unstable but therefore more maneuverable. It's just inertia at work.
I Must say I have thought about it some more and the angular momentum must have some small effect as it is possible to ride and remain upright (albeit for a small distance) with no hands on the handlebars but impossible to remain upright if you are stationary. But you are still nowhere near as stable as you are when actually steering while moving.
+Pete Johnston Maybe the correct phrasing would be that angular momentum is the reason why we can ride a bike with no hands..
Fully Agree. Naive to assume that bicycles, or people for that matter, manage to stay upright due to gyroscopic effect. Bicycles and Airplanes have interesting and important stability functions which a Physics professor should understand more fully. This is a bit of a FAIL I'm afraid. A Bicycle is self-stabilizing (can stay upright without a rider or ridden with no hands) for two reasons: Wheels are self-righting by their nature, as they naturally turn into any direction of lean; and two, the front wheel touch the ground at a point slightly BEHIND the (imaginary) extension of the headstock axle - which induces the wheel to turn in the direction of any sideways force - (try this: hold a bike upright without touching the handlebars, and force the bike to the left, the front wheel will turn left in response - they better the bike, the more sensitive it will be to this motion.)
As another says: replace wheels with a ski, and balance is still achieved. Both a snow ski and water ski will depress until a slight curve exists, and this curve when angled over will result in a corrective turn - tending towards uprightness. The gyroscopic stability of wheels which are as light as possible (unlike in video) is immaterial at slow speeds - and yet bicycles can be ridden at a walking pace. That said, I would think some additional experimentation is in order.
I haven't seen any video about the symbol 't' yet, if you're looking for ideas.
I think he meant without moving the unicycle at all, just using your upper body; probably still possible with a lot of training and the right circumstances, but very difficult. ;-)
It's the Quantum Field Mechanism prime- primarily dominant in the first three phase-states and geometry where the axial-tangential distribution of probability is actively rotating and therefore aligned with a resonance plane tangential to the wheel axle and parallels. Ie of the 3 orthogonal planes, two vertical and one horizontal, the bike and rider have "tuned in" to an inertial probability position, least timing and all that..., and a complete description in the QM-TIME applied principle of the system involving the nature of relative solid and liquid phase-states in 1-0D orthogonality.., is too long for a comment. (?)
The Professor has demonstrated what cannot be easily put into words.
Applying the Quantum Fields Modulation Mechanism to the situation: if gravity is the name for the "cooling" curvature of QM-Time, (inflation is the "heating"), exponential function, then the phase-states spectrum of spacing-timing interference-probability has Pi-i circulation possibilities of orbital/orbits in the general cause-effect of continuous containment->reflection environment of "One Electron" type superposition singularity vanishing point, distribution image of combined Superspin.
So physically rotating an object shifts the tuning of the object's phase-states into the orthogonal-tangential plane, around the Universal zero point axis-vanishing point, the 1-0D prime-timespace dimension and sum-of-all-history now.
"You're supposed to work it out for yourself ", Monty Python. Don't just hang around?
SIGH IN! this made my day
nice vid, I wish of you'd would be my physics prof
5:17 angular momentum doesn't depends of mass distribution. that's about the whole point about its conservation
think he meant given the same angular momentum, angular velocity depends on mass distribution (ie inertia)
@me835 Giddy, I was very Giddy, but I have recovered now.
is the correlation between the angular velocity and radios of the weights linear? i think it is but im not sure
@Koroistro there is no "force" in it...
lol I need a prof like that!
Bowley is completely right. A mountain bikers philosophy is the faster you go the safer you are. People look at you like you are crazy, but PHYSICS PROVES IT!
One thing that confuses me is why angular momentum/velocity/torque is depicted as perpendicular to the axis (right hand rule). Is there actually any force acting in that direction or is it just depicted that way to "help" show how angular momentum is conserved? I'm assuming it's the latter but I'd love clarification on this.
ah, this is fun... Prof. Bowley cracks me up
Wait... Would the theoretical space elevator slow the Earth day, similar to how the distribution of mass affects the speed of rotation? Further more, If the speed does decrease, then what is the difference between that and geo-stationary satalites, or even the regular satalites?
Please Help. Does it mean that bicycle will tend to fall on one side because the L is pointing to one direction?
Where would the world be without George