the chain falling add the speed of the weight.. while the other weight without chain, has not that factor. PS it should be different color weight, so it is easy to write down, the red , the blue, but he would have to spend more money buying 2 sets of pair weights.
"the railing cannot possibly have an effect on the weight until the chain is fully stretched" - I disagree. Consider a whip - the tip goes faster than the speed of sound by first throwing the whip out and then pulling back. This pulling back accelerates the tip before the the whip is fully extended.
@@aalhadsawane3515 If you pull on a chain fast it will move entirely, without it necessarily being fully stretched. The force still propagates through the links.
@@aalhadsawane3515 You could think of it simply as the tension between each set of links, another way of thinking about it is that the chain's energy will be forwarded along the chain to the weight as it comes to a stop.
@@aalhadsawane3515 The chain is fully stretched - just not in one direction. Initially, before he drops the dumbbell, each half of the chain is under tension because the top part of each chain is being held and is supporting the weight of the links hanging downwards. In the following explanation, I'll call the part of the chain hanging from the railing Part 1 and the part of the chain hanging (pulling) on the dumbbell Part 2. When he releases the dumbbell, the railing continues to pull upwards on Part 1 of the chain. This applies tension to the chain that is transferred link-by-link to the bottom of Part 1 of the chain. This tension pulls downwards on Part 2 of the chain and the attached dumbbell, keeping Part 2 of the chain under tension as it falls. This tension causes Part 2 of the chain and the attached dumbbell to fall with a slightly greater acceleration than they would have if gravity was the only force acting on them. The tension is acting on both Part 2 of the chain and the dumbbell as if they are a single mass. So, the acceleration is only a tiny bit larger than freefall (Newton's 2nd law). As the dumbbell continues to fall, Part 1 of the chain gets longer and, therefore, heavier. This increases the tension force applied by the railing to the chain. At the same time, Part 2 of the chain is getting shorter and, therefore, lighter. So, a larger tension is now pulling downwards on a lighter combination of Part 2 of the chain with its attached dumbbell. This causes the dumbbell's acceleration to increase as it falls. You can see this in the video where the two dumbbells have very similar accelerations near the top. But then the chained dumbbell rapidly pulls away from the other dumbbell when it gets close to the ground.
We meet again, fellow traveler. I have received the answer I was searching for, now I must continue my journey through the long forgotten depths of youtube. We'll cross paths again, if the good algorithm will decide that is our destiny. Farewell, fellow traveler, hope you will find the answers you seek.
or another option would be to drop the chained weight with the other end of the chain on the ground. This means the chained weight still has the 'path' but not the whip effect. I would expect the weights to land together in this case. Kicking myself for not doing it while I had the gear.
You can also explain it as follows: The center of mass for the falling part of the chained mass moves up the chain as the bottom part of the chain becomes stationary. So the chained mass' center of mass starts off closer to the ground and thus the travel distance to the ground is smaller. Then, as objects in gravity accelerate equally, the mass with less travel distance lands sooner.
You can think of it as a change in center of mass. The center of mass accelerates at g, but the weight is some changing length above the center of mass. This length decreases as the chain falls, forcing the weight to accelerate faster.
He an Ozzy, hell we should have forgotten to tie him on! 😱 Yeah nah.....that would cause water pollution. 😳 Bugger 😳👍😂 (This is standard Ausie vs. NZ banter. It is neither malicious nor threatening)
The whip acceleration comes from the link at the bottom of the chain as it is doing a 180 degree spin. One end of this spinning link is held at a pivot point by the taut chain above. The center of mass of the link falls at g, but the free end whips at a>g. This puts a force on the free falling link attached to the whipping link, pulling the weight down.
The rotation of the chain links is the key to what is happening to the chain, Muller's talk about tension is just plain wrong. When each link is stopped by the looped chain it pivots as Stephen describes. This moment increases the downward acceleration of the falling chain and transfers kinetic energy from the links which are stopped to the links which are still falling and the dumbbell. The bungee drop is different because the greater elasticity of the bungee cord. This case is more like the falling slinky, the stretched cord (only on the downward leg) provides the additional downward acceleration.
I agree with you. It is the problem I saw before, and what I thought is same with yours . And, I don't think it happens to bungee jump because the rope is light and flexible.
@@HN-nf8yl I think as long as the rope has some weight and some resistance to bending, you can still get this effect. Even with a chain, each link is not perfectly rigid and there is some friction between links. Looking at it this way, it seems like a perfectly flexible whip would be impossible to crack. True?
Considering no mass attached, length l(=l/2+l/2), one end fixed on ceiling, the other in free fall, total mass M, distance from the ceiling x(t), energy conservation gives velocity x’^2 =gx(2l-x)/(l-x) and via Laplacian, acceleration of the free end x”(t)=g(x^2+2l^2-2lx)/(2(l-x)^2) which is greater than g. For x=l x” becomes infinite- whiplash effect !
It looks simpler though, difference in production quality. Or maybe the newer videos cover concepts that take more time to explain - like the logistic equation
@@iamthinking2252_ yeah im not trying to say he didnt improve but his face and acting didnt change much, he was jsut very good at making videos back then, unlike most youtubers
That moment when you lack the fundamental physics needed to understand that they should be the same speed so you say the chain b/c it's heavier...whoops. Learned something today!
I don't think this explanation is accurate. The centre of mass only accelerates down at 9.8 m/s^2 if gravity is the only force acting. In this case, there is an upward force where the chain is attached to the railing, resulting in the whip effect discussed in the video.
Great video! Great demonstration. Also can be applied to show how the end of a whip breaks the sound barrier while the force initially applied has a much lower velocity at the handle.
It's a whip effect. If you did the experiment with the chain in free fall there would be no extra acceleration. Consider what happens when a falling chain link is arrested by the chain. It's momentum has to go somewhere. Some goes into friction, some into stretching the chain, most (I think) into accelerating the weight.
"the chain accelerates the object like a whip would" that may be true, but i thought like, the chain is divided into 3 parts: the part that's fixed in place, the bend, and the end that's tied to the object. And i thought that part one weighs like it would normally, part #2 aka the bend is weightless, since in this case its moving along the chain which leads it down, and part #3 aka the end w/ the object which weighs as much as the object + the chain combined. So if you have a chain tied to an object, of course its gonna fall faster than the normal one!
Makes perfect sense. The chain is accelerating toward the Earth's surface pulling on the attached weight making it accelerate faster than the free weight.
No, that's not what's happening. If that were the cause, then gluing the entire chain to the weight would also make it accelerate faster. The difference is caused by the tension in the chain, which is already there before the weights are dropped.
Another 2020 viewer here. It seems that the potential energy of the chain is converted to kinetic energy of the weight (where else would the extra energy come from?). Since kinetic energy is E=0.5*m*v^2, then lowering the mass of the weight at the end of the chain (but keeping the same chain) would increase the final velocity of the weight. So, it would follow that the chain with no weight would fall even faster than the chain with the weight at the end. If that is correct, then increasing the mass of the weight at the end of the chain makes then end of the chain (and the weight) fall slower, but increasing the mass of the chain makes the end of the chain fall faster. That's worth another test. It would also follow that a tapered chain with the same mass would fall faster than the homogeneous chain (because the mass at the end of the chain is less), which could explain why whips are tapered to a thin end.
For anyone that’s still confused like I was : What he means by accelerating up - as the chain links becomes stationary-is this: the chain below the weight gains momentum so that force is what creates it: imagine a chain link as a ball falling into a u shaped pipe, it will accelerate up out the other side , pushing up on the rest of the chain and since it’s free to move- creates the wobble we see, thus shortening it/pulling it up at the bend- pulling the weight,and chain, down quicker. Your welcome:) My theory is if you could hold the chain perfectly still as it goes down it will fall at the same speed
You are the man. I hope I get on the "who wants to be a millionaire" show and get this question and I just surprise the whole audience by making the quickest decision ever. While looking like a complete genius by my explanation.
yay. got it right. also, the chain overcomes the air resistance that slows the lighter mass of the free one, maintaining acceleration, so if you dropped the chain without having it moored you'd see it hitting ground first. Things with different densities / surface area/ mass only hit the ground at the same time ... in a vacuum. Interesting to learn the second part of the picture
This "whipping" concept blowed my mind... and triggers a couple of questions: -As the chain link comes to the "unfolding" point, the force that accelerates it comes from the link that pulls it from the handrail. Why is this force transferred to the next link, doing the pull force to the weight? -Acceleration under free fall depends on many factors, and the relationship between mass and shape is important. As an example try to do the same experiment with two objects equal in shape and different in mass or with two arrows, one released pointing down and the other pointing sideways. So then... May be the difference in the video is just caused by aerodynamic drag? To check this, I will try to repeat the experiment with just a piece of chain hanging from the weight. (when the pandemic lockdown ends...) Thank you for making our brains to sweat! Great channel!!
When you said the tension caused by accelerating the rope upwards (stopping it's downward fall) caused the weight to fall faster I nearly had my mind blown. Never would have thought of that.
Center of mass, regardless of whether or not it is losing mass. Thus, as it falls, the center of mass becomes just the weight when it hits the ground because it is the length of the fall itself. Were you to have a longer chain, the bottom of the U would hit the ground first, but the weight itself would hit the ground as though it was placed at the center of mass, rather than the initial height because the U is now supported by the ground.
He said in the video, "the chain is falling becomes stationary" So the chain has to be falling attached to the top, this way each little section becomes stationary and the whip effect occurs on the next section. If the chain was on the ground, the links will not become stationary one after another, they will all fall together with the weight all at the same time.
@@marcelo55869 It will actually have a higher speed, although not as much as with the chain attached to the wall (I tested this irl). Because the Speed difference I measured was small, I suspect that this whip effect doesn't have a big effect here (but it certainly also accellerates the Chain. Its a Similar as the law of the lever, just applied for every chain element.) . Instead, the tension in the chain may have a higher effect on accellerating it: Every material stretches a bit when a pulling force is applied to it, so when the chain is dropped, it contracts a bit and therefore additionally accellerates the top of it. That doesnt cause a big speed difference, but the distance between the chain and the other object gets amplified more and more the longer it falls. After all, the material and structure of such a chain strongly affects the outcome of those experiments.
I am a great fan of the channel not because of the physics but because of the choice of experiment to demonstrating the physics and the way of explanation. For example, this could easily be explained by making a free-body diagrams of both the weights but that won't go through a common man's mind and your explanation is like perfect for them. Keep doing such videos.
because the chain and weight are connected, it doesnt matter where the centre of gravity is--all moving parts accelerate at the same rate due to gravity. now if one end of the chain is fixed at the top, like in the video, then you have additional downward acceleration caused by tension on that chain when parts of the chain suddenly decelerate at the bend. the key ingredient is that one end of the chain is fixed so that any tension spikes along the chain will pull the weight at the other end..
2019 --> 2011 Looks like I will go backward in the time since I have seen all the new stuff... At what speed rate should I watch if I want to see all the videos like in 1 week and return back to my time flow? Pls help :(
so now the question is this a liner growth pattern of acceleration or is it exponential growth pattern or I.E. if the chains/rope was longer wound the acceleration continue or would it hit a terminal speed I.E. like a unchained object falling at terminal velocity is there a terminal velocity for the added mass/length of with more length will the speed grow greater and greater?
so we can say simply that a slight impulse is given by the chain due to tension and hence the object tied with the chain gets fall with slightly more acceleration
The center of mass of the system with the chain is lower than that of the system without the chain. If the chain had no mass then the two objects would hit the ground simultaneously. Isn't this an other way to predict the result of the experiment?
You can also see why this happens by considering the centre of mass of the chain. When he drops it, the weight is above the centre of mass of the system (weight and chain), when it lands it is below the centre of mass of the system. Since the centre of mass accelerates due to gravity, you can then deduce that the weight has to have accelerated faster than gravity, if it were to go from above to below the centre of mass
TheDoctor2374 Additional weight doesn't increase the acceleration of a falling object due to the fact that additional weight = additional inertia, and the increased inertia always cancels out the increased acceleration due to the weight, you can see him explain this in the video "misconceptions about falling objects". However if that is not what you meant by your statement, you can just ignore this comment (though it shows why "go(ing) all nerdy" is useful, since it allows people to understand you better as you go into specifics)
MMedic No, you're wrong. Applying weight to an object doesn't make it fall faster. The chain was applying a tension force--that's what made it fall faster.
Tzadeck Why wouldn't applying weight make it fall faster? The chain applies force and the force pulls it down, is that completely wrong? Well it's explained in the video but, I think I'm making _some_ sense
Great video. Conservation of momentum could also be used to explain this. Let's assume half the chain and weight are in motion after a short interval of time, T1. At a later interval when more of the chain is stationary the momentum would have been transferred to the weight and chain still in motion, leading to increased velocity. Basically the momentum of the falling chain is being transferred to the falling weight. Interesting physics.
My intuitive reasoning was that the centre of gravity for the system was lower for the chained weight, and that it still fell at 9.8m/s/s even as it moved toward the weight. Therefore, the weight-chain system didn't have as far to fall. For this reason, I suspect the chained weight would still land first if the loose end of the chain were on the ground.
F you think about it this way... the MASS of the chain/weight combo accelerates, but mass is removed as the acceleration gets going, letting potential energy transfer into the falling chain gaining speed from the process.
the chain has a weight downwards and the object tied to it has also a weight downwards . so the resultant velocity of the object tied to the chain increases.
Not only is it a whip effect but the chain is displacing air in front of the weight. Just like when a skydiver flies beneath another skydiver the top one will drop super fast onto the bottom jumpers' back.
Except that the center of gravity of the ball and chain never hits the ground because the chain is tied to the top of the railing and most of the mass is in the chain. So the chain/ball center of gravity stays well above the ground the entire time and thus the lone weight's center "reaches" the ground first (within the width of the weight)
I thought the chined weight would fall faster because aerodynamics. When a chain link is at the bottom it hits air which slows it down. It then is pulled to the side by the rest of the chin and another link takes it's place. This means that the chined weight will accelerate faster
I think what you really need is a free body diagram of an individual chain link as it reaches the point where it stops falling. That would show you how the tension force from the hanging chain propagates to the falling part of the chain. If the chain was just hanging and not attached to the wall, the mass would fall at 9.8 m/s2 like everything else. We have to show how addition tension force gets into the falling chain to increase the acceleration of the weight.
I know it’s been 10 years but hopefully you still read feedback as I have a question.. Would a LONG chain of this size exhibit the ‘bead siphon’ (mould) effect??? Anyway, your videos are timeless. 👍
It must be frustrating having all these people correct you... It's amazing. They must have there phd as well. Thank you for teaching us new concepts. Also, doing it free to me.
@@mercuryman9142 Actually no. Unless you ejected the poop completely(ie not inside your clothing), your velocity doesn't change because your mass is the same. Now farting is another thing because you are pushing matter away and matter, in turn, pushes you down.
Veritasium I think I have a better answer for this, here it goes the weight tied to the chain and the weight without chain does not he their centre of mass at the same height. The weight tied with the chain have it's centre of mass a slightly lower in space due to the weight of chain. Hence it reached earlier.
Karan Agarwal With this same logic, there will be some point during the drop in which the center of mass of the chain/weight system will move above the weight itself. By the time the weight hits the ground the system's center of mass will be well above the weight. And it's safe to say that if this CoM never reaches the ground, it couldn't possibly beat the CoM of the lone weight. Keep thinking. The answer is already in the comments.
Actually this is not true. The falling system's mass is changing with each passing second. The chains which are fully in tension (not falling) are no longer part of the system since they don't fall with the rest of the mass at all. Therefore the CoM is also moving lower with each passing second until it IS on the ground. Feel free to prove me wrong but this is my explanation.
I prefer the energy explanation, it seems more simple to me. The weight attached to the chain arrives first because the potential energy of the chain is higher when it’s curved up than when it’s straight down. So the energy must go somewhere, which leads to the logic conclusion the the weight must arrive at a higher speed to the ground.
The reason why feathers and bowling balls drop at different rates on Earth is because of atmospheric effects. Bowling balls are better at pushing the air out of the way than feathers, so feathers have much slower terminal velocities and don't fall as quickly.
I was thinking about the centre of gravity of the chain and weight being lower than the c.o.g of the lone weight, and that the free-falling chain's untethered length would be getting shorter and lighter as it fell. That made me pick the correct answer, but I don't know if I chose for the right reasons.
@Steve Mould surely this explains “the Mould effect”. It’s the Mould effect in reverse. As the chain goes into tension it applies an added acceleration to the chain pulling it higher out of the container.
I think Veritasium is the best at explaining the things in his videos. Minute Physics is great as well but I feel like you have to already know a bit of what he's talking about to really understand. Veritasium is good at explaining new ideas to me.
Obviously he didn't drop the weights at exactly the same time. But....we can use the horizontal lines in the stone block wall as a basis of comparison. The weight on the left (his right hand) had a head start and was ahead until the halfway point...afterward the other weight accelerated passed it. I'm no physics major, so here's my guess as to why this happens. The mass of the weight on the left is constantly decreasing as it falls. Think of about it....the mass is the combined weight of the dumbbell plus the weight of the chain above the "slack point" (Or whatever term is correct.) This mass is decreased as the length of the chain above the "slack point" decreases. Since it requires more force to move something that's heavier, can't we assume that gravity has to pull harder on the heavier weight? And since the mass of the object is constantly decreasing, wouldn't that suggest gravity is pulling "harder" than it needs to...thus causing the object to fall faster? I guess we need to try chains of different weights and see what happens. Any input?
That's a good point, gravity's acceleration is proportional so mass doesn't efect the acceleration due to gravity but the chain that is accelerating up is alway the same amount of mass were as it has less less mass to accelerate the farther it falls. Thanks for this point.
AmazingGryphon In a vacuum. In any medium, objects of different mass and density will not fall at the same time. The lack of a medium is what lets objects of different mass and density fall at the same rate.
I have my doubts about upward acceleration and downward accelation being conserved. Another physics experiment with falling chain explains the increased acceleration is due to the rotational acceleration as each link enter the curve at the bottom. I.E. the whipping effect.
Can you do the bungee jumping with another person side by side, but isn't connected with a cord? That would make me believe your theory
underrated
That would prove it
It's all about the scientific method
I volunteer as tribute.
@@victor9 Where you will be connected to the rope and someone else jumps without the rope?
i love how this awnser video has only half the views
James Mitchell people likely had to watch the first one twice to try to figure it out.
Well, there are two other answer videos that probably have views.
I picked the chain but for the wrong reason :(
James Mitchell more than half
the chain falling add the speed of the weight.. while the other weight without chain, has not that factor.
PS it should be different color weight, so it is easy to write down, the red , the blue, but he would have to spend more money buying 2 sets of pair weights.
Its so weird to watch Veritasium without the beard.
His name is Dirk
In this video he looked like ben affleck
@@_adela no
He look so young
I still have mine
"It felt fast. A great increase in speed". What is he comparing this experience to... the time he jumped off the bridge without a bungee cord?
Well... Duhhh!
Anything for science!
nine point eight meaterspersecondsquared
Didn't he skydive at some point? Also if he was falling faster than g then he'd feel the rope pulling him downwards
He was describing the acceleration, which is of course an increase in speed. No comparison there.
"the railing cannot possibly have an effect on the weight until the chain is fully stretched" - I disagree. Consider a whip - the tip goes faster than the speed of sound by first throwing the whip out and then pulling back. This pulling back accelerates the tip before the the whip is fully extended.
@@aalhadsawane3515
You could think of it as two separate tension forces
One from the railing to the bend, one from the bend to the weight
@@aalhadsawane3515 or think of it as conservation of momentum - as some of the chain stops, other parts have to accelerate
@@aalhadsawane3515 If you pull on a chain fast it will move entirely, without it necessarily being fully stretched. The force still propagates through the links.
@@aalhadsawane3515 You could think of it simply as the tension between each set of links, another way of thinking about it is that the chain's energy will be forwarded along the chain to the weight as it comes to a stop.
@@aalhadsawane3515 The chain is fully stretched - just not in one direction. Initially, before he drops the dumbbell, each half of the chain is under tension because the top part of each chain is being held and is supporting the weight of the links hanging downwards. In the following explanation, I'll call the part of the chain hanging from the railing Part 1 and the part of the chain hanging (pulling) on the dumbbell Part 2.
When he releases the dumbbell, the railing continues to pull upwards on Part 1 of the chain. This applies tension to the chain that is transferred link-by-link to the bottom of Part 1 of the chain. This tension pulls downwards on Part 2 of the chain and the attached dumbbell, keeping Part 2 of the chain under tension as it falls. This tension causes Part 2 of the chain and the attached dumbbell to fall with a slightly greater acceleration than they would have if gravity was the only force acting on them. The tension is acting on both Part 2 of the chain and the dumbbell as if they are a single mass. So, the acceleration is only a tiny bit larger than freefall (Newton's 2nd law).
As the dumbbell continues to fall, Part 1 of the chain gets longer and, therefore, heavier. This increases the tension force applied by the railing to the chain. At the same time, Part 2 of the chain is getting shorter and, therefore, lighter. So, a larger tension is now pulling downwards on a lighter combination of Part 2 of the chain with its attached dumbbell. This causes the dumbbell's acceleration to increase as it falls. You can see this in the video where the two dumbbells have very similar accelerations near the top. But then the chained dumbbell rapidly pulls away from the other dumbbell when it gets close to the ground.
We meet again, fellow traveler.
I have received the answer I was searching for, now I must continue my journey through the long forgotten depths of youtube.
We'll cross paths again, if the good algorithm will decide that is our destiny.
Farewell, fellow traveler, hope you will find the answers you seek.
my gratitude, ponyboy
No, please. Don't leave me.
I can't be without you again Mr. Nax FM! DON'T LEAVE ME!
Farewell
Nax FM farewell
Godspeed, my friend. I'll see you on the other side
Are we not gonna talk about how Derek’s Australian accent has basically disappeared compared to when this video was recorded?
Oh my god I didn’t notice at first but it really is there!
@@gradyking4739 Ik and it’s only certain words, so it’s subtle and you just don’t even realize it
I only just realized he was Australian because of his Sydney Uni hoodie
I am Australian so I can barely detect it anyway
As an Australian, I can hear a bit of both accents
or another option would be to drop the chained weight with the other end of the chain on the ground. This means the chained weight still has the 'path' but not the whip effect. I would expect the weights to land together in this case. Kicking myself for not doing it while I had the gear.
this comment has 1 like, zamn
lemme change dat
Nobody:
TH-cam: Let's recommend this video 9 years later...
Hi
It's Young Derek!
we are on the same feed apparently lol
@NilsO78 same here :-)
@@grexursorum6006 Haha :-) Grüße ins Erzgebirge!
These sound like good experiments - you should do them!! (and report what happens)
Noone replied so I did
@@user-lw5oc1tt8k me too
@@nou4898 nice
@@user-lw5oc1tt8k here before it been an hour before the first reply (its 51 minutes ago)
@@user-lw5oc1tt8k what happened :p
You can also explain it as follows: The center of mass for the falling part of the chained mass moves up the chain as the bottom part of the chain becomes stationary. So the chained mass' center of mass starts off closer to the ground and thus the travel distance to the ground is smaller.
Then, as objects in gravity accelerate equally, the mass with less travel distance lands sooner.
Not air resistance?
I can't fault that off the top of my head. See you in a couple of days, maybe :)
This makes the most sense
If he dropped the weight without the chain being attached to the railing then there would be no effect.
Aaawww... stop making me picking the wrong answer. I wanna be right.
+SysGhost then think before you answer
+SysGhost You were right?!?! If you picked this video!
I'm glad my IQ isnt measured on guessework. Even tho i was CORRECT!!
Why? What will you learn?
You can’t learn anything if you never pick the wrong answer
I just noticed if he grows a moustache he would look like Freddie Mercury
Saw it in the exact same moment, that I read your comment
Somewhat... 🤔
2:00 actually... yep... somewhat
No
@@joshuhigashikata9201 I like your name
@@ultralinguistics3083 thank you :)
You can think of it as a change in center of mass. The center of mass accelerates at g, but the weight is some changing length above the center of mass. This length decreases as the chain falls, forcing the weight to accelerate faster.
Thanks. Your explanation helped me conceptualize this better.
He was so scared his inner aussie came out for a few seconds 🤣
He an Ozzy, hell we should have forgotten to tie him on! 😱
Yeah nah.....that would cause water pollution. 😳
Bugger 😳👍😂
(This is standard Ausie vs. NZ banter. It is neither malicious nor threatening)
The whip acceleration comes from the link at the bottom of the chain as it is doing a 180 degree spin. One end of this spinning link is held at a pivot point by the taut chain above. The center of mass of the link falls at g, but the free end whips at a>g. This puts a force on the free falling link attached to the whipping link, pulling the weight down.
you explained that better than the video. thanks for clarifying :-)
The rotation of the chain links is the key to what is happening to the chain, Muller's talk about tension is just plain wrong. When each link is stopped by the looped chain it pivots as Stephen describes. This moment increases the downward acceleration of the falling chain and transfers kinetic energy from the links which are stopped to the links which are still falling and the dumbbell.
The bungee drop is different because the greater elasticity of the bungee cord. This case is more like the falling slinky, the stretched cord (only on the downward leg) provides the additional downward acceleration.
I agree with you. It is the problem I saw before, and what I thought is same with yours
. And, I don't think it happens to bungee jump because the rope is light and flexible.
@@HN-nf8yl I think as long as the rope has some weight and some resistance to bending, you can still get this effect. Even with a chain, each link is not perfectly rigid and there is some friction between links. Looking at it this way, it seems like a perfectly flexible whip would be impossible to crack. True?
When you learn video editing from a former bollywood editor
Considering no mass attached, length l(=l/2+l/2), one end fixed on ceiling, the other in free fall, total mass M, distance from the ceiling x(t), energy conservation gives velocity x’^2 =gx(2l-x)/(l-x) and via Laplacian, acceleration of the free end x”(t)=g(x^2+2l^2-2lx)/(2(l-x)^2) which is greater than g. For x=l x” becomes infinite- whiplash effect !
Amasingly he didnt change in 9 years. He could upload this video today and a lot of people wouldnt even notice
I didn't really notice.
I clicked on the video not knowing how old it was, and to me he looked much different than in new videos.
It looks simpler though, difference in production quality. Or maybe the newer videos cover concepts that take more time to explain - like the logistic equation
@@iamthinking2252_ yeah im not trying to say he didnt improve but his face and acting didnt change much, he was jsut very good at making videos back then, unlike most youtubers
Newer derek probably wouldn't split the demonstration and answer into two videos
That moment when you lack the fundamental physics needed to understand that they should be the same speed so you say the chain b/c it's heavier...whoops. Learned something today!
You just taught me why do ropes/ chains whip in a minute, You legend
oh this guy has been on youtube for over a decade , nice . Thats where the confidence in front of the camera coms from
I don't think this explanation is accurate. The centre of mass only accelerates down at 9.8 m/s^2 if gravity is the only force acting. In this case, there is an upward force where the chain is attached to the railing, resulting in the whip effect discussed in the video.
Great video! Great demonstration. Also can be applied to show how the end of a whip breaks the sound barrier while the force initially applied has a much lower velocity at the handle.
It's a whip effect. If you did the experiment with the chain in free fall there would be no extra acceleration.
Consider what happens when a falling chain link is arrested by the chain. It's momentum has to go somewhere. Some goes into friction, some into stretching the chain, most (I think) into accelerating the weight.
This is very good quality for almost 10 years ago
The chain has an advantage at the end because the short part of the chain acts like a long whip.
The tip of a real whip has a speed above sound.
Well here we are 10 years later with over a million views and counting. Congrats on all the success Veritasium!
"the chain accelerates the object like a whip would"
that may be true, but i thought like, the chain is divided into 3 parts: the part that's fixed in place, the bend, and the end that's tied to the object. And i thought that part one weighs like it would normally, part #2 aka the bend is weightless, since in this case its moving along the chain which leads it down, and part #3 aka the end w/ the object which weighs as much as the object + the chain combined. So if you have a chain tied to an object, of course its gonna fall faster than the normal one!
weight has no bearing on the rate that objects fall
weight doesn't affect gravitational acceleration at this scale
@@user-vk2cd9qw7i how? The chain still weighs at least 2kg, that has to accelerate the object!
Makes perfect sense. The chain is accelerating toward the Earth's surface pulling on the attached weight making it accelerate faster than the free weight.
No, that's not what's happening. If that were the cause, then gluing the entire chain to the weight would also make it accelerate faster. The difference is caused by the tension in the chain, which is already there before the weights are dropped.
"OH MY GAHHHHHHHHD!" That's hilarious, dude.
Another 2020 viewer here. It seems that the potential energy of the chain is converted to kinetic energy of the weight (where else would the extra energy come from?). Since kinetic energy is E=0.5*m*v^2, then lowering the mass of the weight at the end of the chain (but keeping the same chain) would increase the final velocity of the weight. So, it would follow that the chain with no weight would fall even faster than the chain with the weight at the end. If that is correct, then increasing the mass of the weight at the end of the chain makes then end of the chain (and the weight) fall slower, but increasing the mass of the chain makes the end of the chain fall faster. That's worth another test. It would also follow that a tapered chain with the same mass would fall faster than the homogeneous chain (because the mass at the end of the chain is less), which could explain why whips are tapered to a thin end.
Not what I thought was going to happen, awesome
For anyone that’s still confused like I was : What he means by accelerating up - as the chain links becomes stationary-is this: the chain below the weight gains momentum so that force is what creates it: imagine a chain link as a ball falling into a u shaped pipe, it will accelerate up out the other side , pushing up on the rest of the chain and since it’s free to move- creates the wobble we see, thus shortening it/pulling it up at the bend- pulling the weight,and chain, down quicker. Your welcome:)
My theory is if you could hold the chain perfectly still as it goes down it will fall at the same speed
its so sad that 200k people who watched the first video didnt watched this
You are the man. I hope I get on the "who wants to be a millionaire" show and get this question and I just surprise the whole audience by making the quickest decision ever. While looking like a complete genius by my explanation.
“When I went bungee jumping”, that’s a sentence that I will never utter 😬
All bungee jumpers have said what you said at some point.
@@ErikNilsen1337 Yeah, I guess. But I intend to strictly adhere to that rule.
@@rickpontificates3406 So did they.
yay. got it right. also, the chain overcomes the air resistance that slows the lighter mass of the free one, maintaining acceleration, so if you dropped the chain without having it moored you'd see it hitting ground first. Things with different densities / surface area/ mass only hit the ground at the same time ... in a vacuum. Interesting to learn the second part of the picture
greetings peoples who came here from 2020 recommendation
Here. Looking for song name
Hi
Hello fellow travellers
Nearly 2021
yes and no
This "whipping" concept blowed my mind... and triggers a couple of questions:
-As the chain link comes to the "unfolding" point, the force that accelerates it comes from the link that pulls it from the handrail. Why is this force transferred to the next link, doing the pull force to the weight?
-Acceleration under free fall depends on many factors, and the relationship between mass and shape is important. As an example try to do the same experiment with two objects equal in shape and different in mass or with two arrows, one released pointing down and the other pointing sideways. So then... May be the difference in the video is just caused by aerodynamic drag?
To check this, I will try to repeat the experiment with just a piece of chain hanging from the weight. (when the pandemic lockdown ends...)
Thank you for making our brains to sweat!
Great channel!!
Hi, I'm youtube, let's recommend this now, 9 years later!
You're not youtube, you're only Alex and nothing more
When you said the tension caused by accelerating the rope upwards (stopping it's downward fall) caused the weight to fall faster I nearly had my mind blown. Never would have thought of that.
That retaining wall oddly reminds me of Tom Scott's crash and cymbal drop video.
Center of mass, regardless of whether or not it is losing mass. Thus, as it falls, the center of mass becomes just the weight when it hits the ground because it is the length of the fall itself. Were you to have a longer chain, the bottom of the U would hit the ground first, but the weight itself would hit the ground as though it was placed at the center of mass, rather than the initial height because the U is now supported by the ground.
Me watching him change so much from 2011 to 2019 🤩
2:12 put a smile on my face especially with the audio 😂
So if the chain was attached to the ground (or just laying on the ground), the speeds would be equal? Wish you would have shown this.
Yes they would
I don't think so
He said in the video, "the chain is falling becomes stationary"
So the chain has to be falling attached to the top, this way each little section becomes stationary and the whip effect occurs on the next section.
If the chain was on the ground, the links will not become stationary one after another, they will all fall together with the weight all at the same time.
Yes because the whole chain would act as a falling body and there'd be no tension in the chain pulling it down faster
@@marcelo55869 It will actually have a higher speed, although not as much as with the chain attached to the wall (I tested this irl).
Because the Speed difference I measured was small, I suspect that this whip effect doesn't have a big effect here (but it certainly also accellerates the Chain. Its a Similar as the law of the lever, just applied for every chain element.) .
Instead, the tension in the chain may have a higher effect on accellerating it:
Every material stretches a bit when a pulling force is applied to it, so when the chain is dropped, it contracts a bit and therefore additionally accellerates the top of it. That doesnt cause a big speed difference, but the distance between the chain and the other object gets amplified more and more the longer it falls.
After all, the material and structure of such a chain strongly affects the outcome of those experiments.
0:07 love how he sounds American with hard Rs but then has the most Aussie countdown ever 😂
He grew up and went to university in Canada, so sounds more Canadian than American to me.
I actually got this one right this time. I knew tension was to blame.
TH-cam
2012: no wait
2015: nah
2018: not yet
2021: NOW!!
Back when he still conveyed some of that Australian accent!
I am a great fan of the channel not because of the physics but because of the choice of experiment to demonstrating the physics and the way of explanation. For example, this could easily be explained by making a free-body diagrams of both the weights but that won't go through a common man's mind and your explanation is like perfect for them.
Keep doing such videos.
I like how he has just a hint of an Australian accent. lol
Getting this reccomended to me 9 years later brings back some memories.
ayeee
And we’re still throwing people off this bridge in Queenstown, New Zealand! 👍
This channel has come such a long way.
Your scream is hilarious xD in the name of science!
I wanted to post a reply and i saw that this comment is 4 years ago then i decided not to post but i am gonna do it anyway.
The reply " Ikr 😂😂😂😂
@@abdulmuse1507 Ikr
because the chain and weight are connected, it doesnt matter where the centre of gravity is--all moving parts accelerate at the same rate due to gravity. now if one end of the chain is fixed at the top, like in the video, then you have additional downward acceleration caused by tension on that chain when parts of the chain suddenly decelerate at the bend. the key ingredient is that one end of the chain is fixed so that any tension spikes along the chain will pull the weight at the other end..
2019 --> 2011
Looks like I will go backward in the time since I have seen all the new stuff...
At what speed rate should I watch if I want to see all the videos like in 1 week and return back to my time flow?
Pls help :(
Number of videos left÷ 7=videos to watch per day
This is 2020 here to tell you to buy toilet paper, invest in Zoom, and cancel your travel plans. Why? Don't ask, just do it.
you and the physic amazed me once again
I was right! I felt the pressure.
These videos are very interesting, you do a much better job than my actual Physics teacher.
so now the question is this a liner growth pattern of acceleration or is it exponential growth pattern or I.E. if the chains/rope was longer wound the acceleration continue or would it hit a terminal speed I.E. like a unchained object falling at terminal velocity is there a terminal velocity for the added mass/length of with more length will the speed grow greater and greater?
so we can say simply that a slight impulse is given by the chain due to tension and hence the object tied with the chain gets fall with slightly more acceleration
The center of mass of the system with the chain is lower than that of the system without the chain. If the chain had no mass then the two objects would hit the ground simultaneously. Isn't this an other way to predict the result of the experiment?
You can also see why this happens by considering the centre of mass of the chain. When he drops it, the weight is above the centre of mass of the system (weight and chain), when it lands it is below the centre of mass of the system. Since the centre of mass accelerates due to gravity, you can then deduce that the weight has to have accelerated faster than gravity, if it were to go from above to below the centre of mass
I thought that was because chain was applying weight on the object.
I think it's more or less the same thing but you just had to go all nerdy. (I'm talking to the uploader by the way.)
TheDoctor2374 Additional weight doesn't increase the acceleration of a falling object due to the fact that additional weight = additional inertia, and the increased inertia always cancels out the increased acceleration due to the weight, you can see him explain this in the video "misconceptions about falling objects". However if that is not what you meant by your statement, you can just ignore this comment (though it shows why "go(ing) all nerdy" is useful, since it allows people to understand you better as you go into specifics)
Kevin Heng Yes, that was what I meant with my statement. And also, I do know some of the words you used in your comment.
MMedic No, you're wrong. Applying weight to an object doesn't make it fall faster. The chain was applying a tension force--that's what made it fall faster.
Tzadeck Why wouldn't applying weight make it fall faster? The chain applies force and the force pulls it down, is that completely wrong? Well it's explained in the video but, I think I'm making _some_ sense
Great video. Conservation of momentum could also be used to explain this. Let's assume half the chain and weight are in motion after a short interval of time, T1. At a later interval when more of the chain is stationary the momentum would have been transferred to the weight and chain still in motion, leading to increased velocity. Basically the momentum of the falling chain is being transferred to the falling weight. Interesting physics.
omg i went there to bungee jump last year! IT WAS AWESOME
My intuitive reasoning was that the centre of gravity for the system was lower for the chained weight, and that it still fell at 9.8m/s/s even as it moved toward the weight. Therefore, the weight-chain system didn't have as far to fall. For this reason, I suspect the chained weight would still land first if the loose end of the chain were on the ground.
F you think about it this way... the MASS of the chain/weight combo accelerates, but mass is removed as the acceleration gets going, letting potential energy transfer into the falling chain gaining speed from the process.
Also thought of this. You lose mass but keep the momentum.
the chain has a weight downwards and the object tied to it has also a weight downwards . so the resultant velocity of the object tied to the chain increases.
TH-cam
2011: no
2012: nah
2013: not yet
jk, I’m not doing this silly joke.
k
THANK YOU
If he wanted to test out his theory, he could've jumped from the bridge without the bungee jump to compare.
I was wrong... I said the free weight, because I thought the friction from the chain unraveling would slow it down...
The free weight starts faster, bc the chain adds to the drag, but around the midway point, it starts pulling and the speed increases super fast.
Same
Not only is it a whip effect but the chain is displacing air in front of the weight. Just like when a skydiver flies beneath another skydiver the top one will drop super fast onto the bottom jumpers' back.
I surely would not have understood this 9 years ago.
Thank Y o u T u b e.
Except that the center of gravity of the ball and chain never hits the ground because the chain is tied to the top of the railing and most of the mass is in the chain. So the chain/ball center of gravity stays well above the ground the entire time and thus the lone weight's center "reaches" the ground first (within the width of the weight)
Now I know one more reason why the write massless string at the end of questions.
+Adarsh Singpuri Unfortunately, because of that I can't figure out the FBD for the chained mass. I messed up the answer.
@@supreetsahu1964 if the chain is massive then it becomes more of a rotational motion question!
I thought the chined weight would fall faster because aerodynamics. When a chain link is at the bottom it hits air which slows it down. It then is pulled to the side by the rest of the chin and another link takes it's place. This means that the chined weight will accelerate faster
Wow this was so long ago
Way to go, man. Instead of explaining the physics to him, you just insulted him. Fantastic work.
Your left hand is covered in chocolate......Let me just finish my calculations...Yes, yes! That is why it hit the ground first.
I think what you really need is a free body diagram of an individual chain link as it reaches the point where it stops falling. That would show you how the tension force from the hanging chain propagates to the falling part of the chain. If the chain was just hanging and not attached to the wall, the mass would fall at 9.8 m/s2 like everything else. We have to show how addition tension force gets into the falling chain to increase the acceleration of the weight.
I know it’s been 10 years but hopefully you still read feedback as I have a question..
Would a LONG chain of this size exhibit the ‘bead siphon’ (mould) effect???
Anyway, your videos are timeless. 👍
It got me wondering about the exact same thing
It must be frustrating having all these people correct you... It's amazing. They must have there phd as well. Thank you for teaching us new concepts. Also, doing it free to me.
Fascinating. Now, I crapped myself when doing a bungee jump. How does _that_ affect my acceleration?
Depends. Crapping with head upright will slow u down. Crapping with head down legs pointing up will speed u up!
@@mercuryman9142 Actually no. Unless you ejected the poop completely(ie not inside your clothing), your velocity doesn't change because your mass is the same. Now farting is another thing because you are pushing matter away and matter, in turn, pushes you down.
What a young man this is.
Veritasium I think I have a better answer for this, here it goes
the weight tied to the chain and the weight without chain does not he their centre of mass at the same height. The weight tied with the chain have it's centre of mass a slightly lower in space due to the weight of chain. Hence it reached earlier.
i was searching such a comment. i also have this explanation.n it's better
Karan Agarwal With this same logic, there will be some point during the drop in which the center of mass of the chain/weight system will move above the weight itself. By the time the weight hits the ground the system's center of mass will be well above the weight. And it's safe to say that if this CoM never reaches the ground, it couldn't possibly beat the CoM of the lone weight. Keep thinking. The answer is already in the comments.
Actually this is not true. The falling system's mass is changing with each passing second. The chains which are fully in tension (not falling) are no longer part of the system since they don't fall with the rest of the mass at all. Therefore the CoM is also moving lower with each passing second until it IS on the ground. Feel free to prove me wrong but this is my explanation.
I prefer the energy explanation, it seems more simple to me. The weight attached to the chain arrives first because the potential energy of the chain is higher when it’s curved up than when it’s straight down. So the energy must go somewhere, which leads to the logic conclusion the the weight must arrive at a higher speed to the ground.
Hey, I know where that bunging place is in, it's in New Zealand! I've been there.
Kawarau? I've jumped from there!
The reason why feathers and bowling balls drop at different rates on Earth is because of atmospheric effects. Bowling balls are better at pushing the air out of the way than feathers, so feathers have much slower terminal velocities and don't fall as quickly.
@ASTROTZUR you can find a lot of good explanations on the web, just google 'acceleration of a bungy jumper'
I replied to a 9 year old Comment
I replied to a 11 year old comment , someone please keep this chain alive.
@@BruhGamer05 I replied to an 11.42 year old comment.
I was thinking about the centre of gravity of the chain and weight being lower than the c.o.g of the lone weight, and that the free-falling chain's untethered length would be getting shorter and lighter as it fell.
That made me pick the correct answer, but I don't know if I chose for the right reasons.
The answer video got recommended before the question video
BTW this is a me from 2020 (for those watching 20 years after 2020
@Steve Mould surely this explains “the Mould effect”. It’s the Mould effect in reverse. As the chain goes into tension it applies an added acceleration to the chain pulling it higher out of the container.
He sounds so dopey at 0.5x speed
sooo true
its actually really funny, watching him jump and fall in slow motion, he sounds really funny and his body is flailing slowly too
funny stuff
I think Veritasium is the best at explaining the things in his videos. Minute Physics is great as well but I feel like you have to already know a bit of what he's talking about to really understand. Veritasium is good at explaining new ideas to me.
Obviously he didn't drop the weights at exactly the same time. But....we can use the horizontal lines in the stone block wall as a basis of comparison. The weight on the left (his right hand) had a head start and was ahead until the halfway point...afterward the other weight accelerated passed it. I'm no physics major, so here's my guess as to why this happens.
The mass of the weight on the left is constantly decreasing as it falls. Think of about it....the mass is the combined weight of the dumbbell plus the weight of the chain above the "slack point" (Or whatever term is correct.) This mass is decreased as the length of the chain above the "slack point" decreases. Since it requires more force to move something that's heavier, can't we assume that gravity has to pull harder on the heavier weight? And since the mass of the object is constantly decreasing, wouldn't that suggest gravity is pulling "harder" than it needs to...thus causing the object to fall faster?
I guess we need to try chains of different weights and see what happens. Any input?
LOL, didnt read!
joestl314 Wrong. It doesn't matter how much mass it has, as gravity pulls down on it at the same rate. He explained why it happened in this video.
That's a good point, gravity's acceleration is proportional so mass doesn't efect the acceleration due to gravity but the chain that is accelerating up is alway the same amount of mass were as it has less less mass to accelerate the farther it falls.
Thanks for this point.
AmazingGryphon True but he also let them go at didferent times as u see in slowmotion
AmazingGryphon In a vacuum. In any medium, objects of different mass and density will not fall at the same time. The lack of a medium is what lets objects of different mass and density fall at the same rate.
I have my doubts about upward acceleration and downward accelation being conserved. Another physics experiment with falling chain explains the increased acceleration is due to the rotational acceleration as each link enter the curve at the bottom. I.E. the whipping effect.