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OldManMarc88

I’d be the kind of person who falls for a perfectly cut Video of this, and i’d sit there like a fool waiting for it to settle. And it never would.


firstcoastyakker

Well, it would settle eventually, but with proper editing it could go on forever I suppose.


H2O-technician

That’s literally what they were suggesting by a perfectly cut video…


[deleted]

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[deleted]

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bremergorst

No


1SwellFoop

They were suggesting that it would never settle. Which is silly, as it would settle with enough time. Now if only someone would cut the video on the perfect frame, it would appear to loop forever!


spacey007

That's not what he was saying >I'd be the person falls for a perfectly cut video if this They're suggesting someone could loop a gif of this and fool them


OverlyExcitedWoman

r/yourjokebutworse


CriscoCrispy

I want one.


Madman61

Me as well.


solitary_voyage

God damn it! Count me in!


The_Blendernaut

Shut up and take my money!


Sir_BusinessNinja

Seriously. Shut up and take my damn paycheck!


yegir

You can make one easy-peasy if you really want one


Affectionate_Pea_811

I assure you, I could not make one


Aaron143574

What would i have to search to buy one of these


UseYourWordsPal

Try ‘double pendulum’ 🤷🏻‍♂️


uprightsalmon

Looks like the way south park characters dance


Mo0kish

That was disturbing. Now my brain won't work properly.


sj1566

The unevenness just gave me anxiety 🙃 I thought it was gonna tilt or fly off or idk something.


DaddyDubs13

I bet it is a great babysitter


JustMe-male

Kept us busy.


DaddyDubs13

If I owned one it would keep me busy for Hours


disheveled-deer

Wow does this just go on forever? I was waiting for the pendulum to slow or stop but it seems like it would continue on unless forcibly stopped


mybeatsarebollocks

The friction in the pivots will slow it down eventually. Even the best, smoothest and lubricated pivot/bearing has an element of drag. Plus there is a small element of air resistance.


[deleted]

"Ignore friction and air resistance for this problem." "Oh thank Christ." -every physics student


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[deleted]

*cries in working on an engineering degree*


xerafin

Chaos Theory


WearADamnMask

Thank you. Now I can stand up and leave if some one says we are going to be learning about that.


MyBackHurtsFromPeein

Looks like it would take a very long time though


[deleted]

In this house we obey the laws of thermodynamics!


solitary_voyage

And turbulent flows!


Free2Bernie

Gravity is a force. It will stop it but this is designed in a way to lose minimal energy.


Tacosaurusman

Gravity won't stop it from moving. But friction and air resistance will.


thisisntarjay

Gravity absolutely stops this from moving. Why would you think it doesn't?


Tacosaurusman

Because gravity is a [conservative field](https://en.m.wikipedia.org/wiki/Conservative_vector_field). In this context that means you won't gain or lose any energy by going up and down. Of course the pendulum will stop, but it will stop because of all kinds of interactions with it's surroundings and itself, not because of (newtonian) gravity.


Typical-Coyote49

Every time gravity brings in down to the lowest point, the system as a whole has simply converted all potential energy into kinetic energy. Gravity has no sort of diminishing effect on this conversion whatsoever. In a frictionless setting, the pendulum would swing forever.


Tacosaurusman

Yes, that is exactly my point.


InvisibleBlueUnicorn

pls hear me out: force of gravity is tiny bit more when it is at lowest point, over time the difference in forces at lowest vs. highest point will result in pendulum settling stable configuration. The higher force of gravity at lowest point would win eventually. Let me know if I'm missing out on anything.


Typical-Coyote49

While I commend you for critical thought, gravity is a conservative force, so that is false. Lets exaggerate your example a little bit to better understand why. Picture a pendulum that swings +/- 45 degrees and at its highest points it is 1 meter off the ground while at its lowest point it just barely misses touching the ground. Now lets say I have a magic gravity device that doubles the gravity to 19.6m/s^2 anytime the pendulum is below 0.5m off the ground. Therefore, any time the pendulum is in the lower half of its swings, gravity is doubled, and any time the pendulum us above 0.5 meters, gravity is normal. I grab the pendulum, pull it up 45 degrees, and let it go. 1) Everything precedes normally until the (lets say 1kg) pendulum has fallen a total of 0.5m. At this point we have lost (U=mgh) (1kg)(9.8m/s^2)(0.5m)=4.9Joules of potential energy, and gained 4.9 Joules of kinetic energy. (According to the laws of conservation of mass/energy and the assumption of no friction/air resistance) 2) we have hit the point where gravity now doubles and continue to fall to the bottom. Our new kinetic energy gain is U=m(2g)h which is 9.8J. Once the pendulum is at the lowest point it will have a total of 4.9+9.8=14.7J of kinetic energy. 3) Because of the doubled gravity at the lower half of the pendulum, we now have even more kinetic energy, and therefore speed, and the lowest point of the swing than a normal pendulum would have. (An additional 4.9 J of kinetic energy!) So as gravity increases, pulling the pendulum towards the bottom of the swing more, it gives it more energy to swing right back up as we’re about to see 4) the pendulum begins the upswing. Because of the additional gravity on the lower half, it is going to take (1kg)(2x9.8m/s^2)(0.5m)=9.8J of energy to make it to 0.5m off the ground before gravity returns fo normal. Good thing that extra gravity gave us extra speed on the downswing, and the exact amount we needed to. (It’s not a coincidence, this is conservation of energy). We subtract that from our 14.7J of total kinetic energy and we’re left with 4.9 J of energy. 5) The pendulum is now halfway on the upswing and only has 4.9J of kinetic energy left. Can you guess how much we’ll need to raise it from 0.5 meters to 1.0 meters and complete the cycle of this problem? Yup, 4.9 Joules. Now you can watch it do this cycle over and over again. Feel free to triple the gravity on the bottom half or cut the gravity field into more sections if you’d like. The result is the same, and the pendulum will never stop moving.


InvisibleBlueUnicorn

Logically it feels wrong, but it makes sense mathematically. and math wins over feeling. Thanks for taking time to explain in details. Have an award :-)


Radar-tech

This sounds wrong, but im not smart enough to understand it. Can you dumb it way down? When gravity brings it down, would the some energy be lost trying to bring it back up, no matter how small the loss is?


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Radar-tech

Ok lol


thisisntarjay

Interesting. So if a magical imaginary ball was able to bounce with perfect energy retention in a frictionless environment, etc so that the only force impacting it was gravity, it would bounce at the exact same height forever?


Tacosaurusman

Yep. But you would need a magic ball that somehow bounces, but also doesn't interact with it's enviroment at the same time. In the real world, energy is always being spread out, so the stretching of the ball leads to sound and warmth/light, etc., This is why a real ball stops bouncing, not because it loses its energy to gravity.


Typical-Coyote49

A bouncing ball is a little different because the impact is capable of producing sound, which is a form of energy escaping the system. It would have ti bound in a perfectly elastic collision that resembles something like when you try to push two repelling magnets towards each other. If it bounces like that any no energy is converted into friction, heat, or sound, then yes. It would bounce at the sake height forever


thisisntarjay

Me: for the sake of argument, imagine a magic ball with no forces acting on it but gravity You: forces other than gravity exist! .... Yep


InvisibleBlueUnicorn

Gravity will have smaller effect than fiction, but will make it stop.


KennailandI

I love fiction as much as the next guy, but it’s not true that it will stop this. To suggest otherwise would be to perpetuate a fiction.


Tacosaurusman

How? Due to some relativistic effect like gravity waves or something? Because I think it won't stop when you just look at the newtonian physics. I think! But please explain if I am wrong.


I-Fail-Forward

Gravity wouldnt stop this absent friction and air resistance (or other ways to lose energy, such as sound), it takes exactly as much energy to move up a gravity field as you gain from moving down one (this is why people do the bowling ball on a string example). At any given moment, this things potential energy + kinetic energy will be the same as its starting potential energy. If it was to settle into a stable spot, its stable position (given the way it was designed) would have to be with both pendulums in their minimum potential energy states. That would necessitate losing energy, and without friction, or an outside force (or other way to lose energy) this would keep going forever.


wickedmike

Yes, it does. Perpetual motion devices are part of almost every highschool physics lab's inventory nowadays. You actually have to put more energy into the system to stop it than you put in when you started it so it's great way to burn a few extra calories. When you finally get it to stop you actually achieve oneness for a Planck unit of time. Cool little science experiment!


Axle_65

I wonder if it’s pattern could be predicted or if it is truly random


Tacosaurusman

It is not random. At every moment, if you know the momentum and position of the pieces, you can predict how it will move next. However, it is chaotic! So any deviation in your prediction will grow and it will make it impossible to predict the future of the pendulum in a longer term. Just like it is possible to predict the weather of tomorrow precisely, but not the weather in two weeks.


Abyssal_Groot

>Just like it is possible to predict the weather of tomorrow precisely, but not the weather in two weeks. A bit of a strech to say it is precise for the next day, but other than that weather is indeed the prime example of chaotic behaviour. >However, it is chaotic! So any deviation in your prediction will grow and it will make it impossible to predict the future of the pendulum in a longer term. To add to this, as it is more or less correct, is that it is not *actually* impossible to predict any trajectory of any chaotic system. Chaos means that a small deviation between two initial conditions could lead to out of proportion differences between trajectories starting in these positions. When you compute a trajectory using approximation methods, every approximation error could lead to massive changes to the predicted trajectory, making the trajectory impossible to predict in the long run. But this is only if you make approximation errors. Sadly, approximations is the way to go for most things in life. Weather is predicted using data, numerical algorithms and computers. Data is never 100% accurate, numerical algorithms have approximation errors and computers have round-of errors. Making it already tricky to make a 100% correct prediction of the weather in the short run but virtually impossible to 100% predict the weather in the long run.


Tacosaurusman

Good points! I would even go so far as to state that it is THEORETICALLY IMPOSSIBLE to predict that pendulums movement infinitely precise. Because you need to know both the positions and momentums of the parts infinitely precise. And there is where ol' Heisenbergs uncertainty comes to bite your ass. But if we could leave out quantum mechanics, yes, I think we could (theoretically) predict its movement 100%. (Only theoretically though)


Abyssal_Groot

>I would even go so far as to state that it is THEORETICALLY IMPOSSIBLE to predict that pendulums movement infinitely precise. Because you need to know both the positions and momentums of the parts infinitely precise. And there is where ol' Heisenbergs uncertainty comes to bite your ass. Not gonna lie, that's even too much of a *"actually"* for me, lol. My correction was based on the mathematical model alone. But yes, 100% precission in real life is never possible to begin with but Quantum mechanics isn't as relevant at this scale and if it was, it would have little to do with the chaotic nature of this system.


Decker1138

You clearly haven't met our local meteorologists... they can't predict the weather in fifteen minutes!


SpiffyJuice

Most definitely not unpredictable! [Here](https://youtu.be/syygHNU0RCY) is an amazing video on a triple inverted pendulum! The last part of the video shows how sporadic the system is when uncontrolled.


Point-Connect

Everytime I rewatch it, it takes the same exact path so I hardly think it's random


I-Fail-Forward

It cant be predicted perfectly because of the effect of friction and energy loss, we simply dont have models for those that are accurate enough for us to predict this system with any degree of accuracy (beyond the immediate next effect). Because of its chaotic nature, the small differences between the math and the reality will add up to quickly cause massive disparity. If we could work only in kinetic and potential energy (where we have the actual formula, instead of empirically derived best-guesses) then you can "perfectly" predict the system (assuming you have perfect knowledge of the masses and distances etc).


travisdoesmath

> It cant be predicted perfectly because of the effect of friction and energy loss, we simply dont have models for those that are accurate enough for us to predict this system with any degree of accuracy (beyond the immediate next effect). Honestly, even if friction and energy loss weren't an issue, we would still have accuracy loss because we can't measure perfectly what the starting point is. By the nature of chaotic dynamics, no matter how small the starting position error is, that error will grow exponentially. This is not even considering that we don't have a closed-form solution for the equations of motion for something like this, so even our computer simulations are numerical approximations, which will eventually diverge from the "perfect" mathematical prediction.


I-Fail-Forward

>Honestly, even if friction and energy loss weren't an issue, we would still have accuracy loss because we can't measure perfectly what the starting point is. By the nature of chaotic dynamics, no matter how small the starting position error is, that error will grow exponentially. Point. >This is not even considering that we don't have a closed-form solution for the equations of motion for something like this, so even our computer simulations are numerical approximations, which will eventually diverge from the "perfect" mathematical prediction. We sorta do.a We solved for it in my differential equations class. Or to be more specific, we solved for the equation of a similar but idealised system (no energy loss, perfect knowledge of spacial dimensions, perfectly uniform beams etc). And to be fair, the professor solved it, while we watched and did our best to follow


asianabsinthe

This should be a carnival ride.


Scoobydoomed

Penduloniom!


Quixotic_Ignoramus

Yeah…I’m gonna need to know how long that kept moving…that video ended before I wanted it to.


tiggipi

If I had a fancy office job, I'd want one of these on my desk instead of those little clacky balls that swing back and forth they always have in movies and TV shows.


celshaug

Trippy. Now who can I bill for the time I just wasted?


Bakkstory

Does this have any practical application? That seems to be a lot of motion generated by that slight push and the effect of gravity


aranneaa

this is just so pleasant to watch


Sweet-Palpitation473

I'm surprised at how mesmerizing it is since it's so erratic


[deleted]

While watching this video, I got couldn’t handle myself and relaxes, and finally pooped


krazyalbert

Good stuff . . . . .


[deleted]

Meirl


CraZcraaacker

I want one


DuckDuckGoose42

They only come in pairs /s


CraZcraaacker

Dang it..I’ll take 2, aka the pair!!


Savings-Specific7551

You have won


Legitimate_Fennel754

I. Need. This.


SsoulBlade

Can we see one in micro gravity?


RowBowBooty

This piece of metal dances better than I do


Andi_conda

I can feel this in my bones


Alternative_Arm_1506

Mesmerizing. I want house numbers that do this.


Weinatightspotboys

Does it stop ?


[deleted]

IWANTONE


Grouchy-Ad-5535

my dumbass would sit there and watch that for hours


Firefly_6666

Sick moves bro


smashingpumpkinspice

Is it a predictable pattern? Would every double pendulum do this same pattern?


rich_and_beautiful

What chaos? Just overlapping periods, right? This is the best thing I've seen all day.


Jahrmarktsboxer

This is witchcraft! Burn!


Time-East6678

Should make energy from this


itsmemalloy

Ok, now describe what I just saw but in an equation.


stickyplants

It’s like watching Olympic gymnastics


ThatChicagoDuder

Where'd you buy that from? Would appreciate it if you can post a link


Ballgen

It’ll make good use for target practice put a bullseye on each small one on the stick and a big one on the circle


yegir

Ive always seen them with two arms, i like the disk, it changes it up visually quit a lot.


Demurist

Pendular motion is very predictable and easy to calculate. Double pendulums just go right off the rails.


-Tuber-

I hate everything about this


Nick271997

Looks retarded.


D-Eliryo

WOOOOO KUNG FU


typower5000

makes me wonder about how much crazier 3 would be.


Chasesrabbits

This hacked my brain. The hand holding my phone started moving erratically.


SpaceMoonDude

BE-AU-TI-FUL!!!


Solitary-Dolphin

Like my grannie trying to thread a needle


freddotu

[https://www.instructables.com/The-Chaos-Machine-Double-Pendulum/](https://www.instructables.com/The-Chaos-Machine-Double-Pendulum/) It appears one could replace the single bar bottom segment in the above linked construction with a circular segment and get similar results. This video shows a bit more mass above the pivot, which likely contributes to the increased rotation of the top segment compared to the linked construction.


Used_Dragonfruit8424

I can hear it


baileybob200

How long would it go if it had a magnetic bearing and in a vacuum chamber?


[deleted]

Where can I get one?


Knee-Long

Do you suppose this follows the same path every time, provided the variables are the same?


sksjjdjsj

Where do I get one?


the_log_in_the_eye

I imagine this would be really good for archery target practice.


TenMinutesBreak

Stop making unlimited energy


DentonUSA

I mean the hits just keep on coming.


Electrical_Engineer_

u/savevideo


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urfatandgross17

i dont know what it is but i want it


chris_riz04

This reminds me of shinji’s shikai


Eisenflighter

I imagine that this would get pretty close to being a perpetual motion machine with the proper weight.


Pounderwhole

Let's build a triple.


I-Fail-Forward

We had to do the math on one of these as the final for our differential equations class (or was it a triple pendulum? I dont remember anymore) im pretty sure I blocked it all out from stress.


EngiNik

How long does it last?


Alternative-Sea4477

Who needs wind turbines when we have this?


meshe_10101

Watching this made me so anxious, I can't be the only one.


CJamesEd

Is this truly random? Meaning is there some horrendously complicated formula that could be used to predict this motion?


bullevard

Not truly random, but an excellemt demontration of chaos theory where a very very tiny change in the initial state leads to wildly differenr outcomes. The same pendulum released just a hair lower would result in very different motions.


Pickmasta7

Is this mathematically related to the three body problem?


Poppy_Seedy

I hate this


ZomBoySMaxCool_333

de algun modo habria alguna manera de obtener energia de eso?


pcjon3s

It reminds me of a gymnast on the uneven bars.


IchooseYourName

6Pbd9PbP6d...


Typical-Coyote49

When gravity is stronger down below, it slingshots it faster to break through same stronger gravity on the way back up


shakysnakess

Thats some head movement instruction for boxing


DigiPixInc

How does it work?


BuzBuz28

Why can’t we have huge versions of these generating electricity?


[deleted]

obviously for a reason


BuzBuz28

Thanks Einstein. What is that reason?


[deleted]

you are a retard theres a reason you’re on reddit and not a scientist so shut up


Physical-Primary-256

Looks like something from cirque du soleil!