Newton's third law problem.

[electrodacus]

The vehicle will move to the right, obviously.

Until you can see that, your reasoning is defective, and many things you try to deduce with your defective reasoning will be wrong.

The reason nobody will debate with you is not because it is boring, but because it is pointless. Since you cannot, or will not, understand, there is no point trying to explain anything to you.

Have you looked at the lever version? See attachment if not.
Do you still think it will move to the right ? If so explain how F2 can be different from F1.

[IanB]

The vehicle will move to the right, obviously.

Until you can see that, your reasoning is defective, and many things you try to deduce with your defective reasoning will be wrong.

The reason nobody will debate with you is not because it is boring, but because it is pointless. Since you cannot, or will not, understand, there is no point trying to explain anything to you.

Have you looked at the lever version? See attachment if not.
Do you still think it will move to the right ? If so explain how F2 can be different from F1.

The green bar will move to the right, obviously (again).

I do not care about the value of F2 (or indeed F1). They are irrelevant to the outcome.

See the attached animation for the wheeled cart example. The cart moves to the left when the belts under the wheels move to the right. This is a pure mathematical model. There is no slip, no energy storage, no hysteresis, no anything of that. The observed outcome is a simple mathematical fact arising from the configuration of belts, wheels and axles.

[electrodacus]

The green bar will move to the right, obviously (again).

I do not care about the value of F2 (or indeed F1). They are irrelevant to the outcome.

See the attached animation for the wheeled cart example. The cart moves to the left when the belts under the wheels move to the right. This is a pure mathematical model. There is no slip, no energy storage, no hysteresis, no anything of that. The observed outcome is a simple mathematical fact arising from the configuration of belts, wheels and axles.

(Well, it seems the forum strips the animation. I'll have to try another way.)

Yes there is no animation but I think I saw that some time ago if I'm not mistaken.

You need a physical not mathematical model. Even the lever can move if you apply an external force other than F1 but there is nothing other than F1 in this setup.
It seems you ignore the lever model. You do care what F1 is in relation to F2 if you want to understand how this vehicle can move. Because is clear it can not move if you remove the stick slip and or energy storage.

[PlainName]

the vehicle works the same way with charging and stick slip hysteresis as there is no other way for the vehicle to work

That, there, illustrates why you will never get this. You start out 'knowing' it won't work, so therefore nothing anyone can do or suggest will show it working because, well, you know it can't.

Just for once, try NA's suggestion without a preconceived idea and see what happens. Once you have uncontaminated experimental data you can argue about how it came about and what it means, and refine the experiment for more data if necessary.

[IanB]

It seems you ignore the lever model. You do care what F1 is in relation to F2 if you want to understand how this vehicle can move. Because is clear it can not move if you remove the stick slip and or energy storage.

And yet the green bar moves to the right with no stick slip or energy storage needed. How do you explain that?

[electrodacus]

And yet the green bar moves to the right with no stick slip or energy storage needed. How do you explain that?

The green bar will not move to the right without both stick slip and and energy storage.

I also saw your animation, and you need to keep one of two surfaces fixed (ground reference).  Then see if your math still works.

[IanB]

I also saw your animation, and you need to keep one of two surfaces fixed (ground reference).

Why? You think it is less likely for the cart to move with one belt stationary than with both belts moving?

If you want the left belt to be stationary, just make that the frame of reference and follow it along with your eye. It is exactly the same equations.

[electrodacus]

That, there, illustrates why you will never get this. You start out 'knowing' it won't work, so therefore nothing anyone can do or suggest will show it working because, well, you know it can't.

Just for once, try NA's suggestion without a preconceived idea and see what happens. Once you have uncontaminated experimental data you can argue about how it came about and what it means, and refine the experiment for more data if necessary.

I made the experiment's and all show exactly what I'm saying.
Not sure you saw the video where I remove the slip at the front wheel and vehicle as expected was dragged in the direction of the treadmill as it is as I say a locked mechanism.
It should be easy to see that the mechanism is locked if you look at the lever version of the same mechanism.

[IanB]

It should be easy to see that the mechanism is locked if you look at the lever version of the same mechanism.

Is the orange line a rope? And are the yellow circles hinges? And if so, how can it be locked with so many movable elements present?

[electrodacus]

Why? You think it is less likely for the cart to move with one belt stationary than with both belts moving?

If you want the left belt to be stationary, just make that the frame of reference and follow it along with your eye. It is exactly the same equations.

I guess you can not do what you are asking me to do.
Fortunately I can imagine what happens if you have the left belt stationary.   I guess you need to do the math to know that.

[electrodacus]

Is the orange line a rope? And are the yellow circles hinges? And if so, how can it be locked with so many movable elements present?

Yes and yes.
There are movable elements but treadmill can apply F1 to the left so the mechanism as it is, is no different from a solid rock.
And I could add the other rope below the green beam but it makes no sense for the forces in this direction as that plays no role here.

[IanB]

Fortunately I can imagine what happens if you have the left belt stationary.

No need to imagine, we know that the cart moves to the left.

I guess you need to do the math to know that.

Yes, it is the math that gives us that result.

There are movable elements but treadmill can apply F1 to the left so the mechanism as it is, is no different from a solid rock.
And I could add the other rope below the green beam but it makes no sense for the forces in this direction as that plays no role here.

Why are you bringing forces into the analysis? This is just a misdirection to send the discussion in the wrong direction.

This is a simple problem of mechanics. The only important variables are the (x, y) coordinates of the pivot points in the mechanism and the connections between them. If you write down the linking equations you will see that the mechanism is not at all fixed and is quite free to move.

[electrodacus]

No need to imagine, we know that the cart moves to the left.

Yes, it is the math that gives us that result.

So you have the fixed ground on the left and the treadmill that moves to the right 3 squares.
How many squares does the vehicle move to the left ?
I think you need to make that animation to see the problem.

Why are you bringing forces into the analysis? This is just a misdirection to send the discussion in the wrong direction.

This is a simple problem of mechanics. The only important variables are the (x, y) coordinates of the pivot points in the mechanism and the connections between them. If you write down the linking equations you will see that the mechanism is not at all fixed and is quite free to move.

So asking to prove by showing how F2 can be larger than F1 is a misdirection ?
"free to move" how ? the only two places you can interact with that are at F1 and F2
Since you can not have F1 without F2 and F2 is opposite and equal it means it can not move.
Just build that mechanism have the leg with F1 in one in right hand and the leg with F2 in the left hand.
Keep the left hand stationary and push with the right hand towards the left hand and see if anything moves.
Whatever force F1 you apply with the right hand will be equal and opposite to the force you will feel against the left hand.

[IanB]

So you have the fixed ground on the left and the treadmill that moves to the right 3 squares.
How many squares does the vehicle move to the left ?
I think you need to make that animation to see the problem.

The animation is already made, it is posted above.

With the fixed ground on the left the treadmill moves to the right one square. When this happens the vehicle moves two squares to the left.

Just build that mechanism have the leg with F1 in one in right hand and the leg with F2 in the left hand.
Keep the left hand stationary and push with the right hand towards the left hand and see if anything moves.
Whatever force F1 you apply with the right hand will be equal and opposite to the force you will feel against the left hand.

You have the question, you build it. This one is simple to make, you can construct it out of cardboard, paper fasteners, sticky tape and string.

[electrodacus]

The animation is already made, it is posted above.

With the fixed ground on the left the treadmill moves to the right one square. When this happens the vehicle moves two squares to the left.

I guess you can not see the problem as you concentrate only on the math with zero connection to physics.
It is OK for you that an invisible hand pushes the vehicle and is not actually powered by the treadmill. 
Also do you observe that in reality ? The vehicle with this gear ratio moves at 2x the speed relative to ground vs the treadmill 1x relative to ground ?

You have the question, you build it. This one is simple to make, you can construct it out of cardboard, paper fasteners, sticky tape and string.

Why will I need to build that ? I already had the vehicle which is the same thing.
You just seems to not understand what the problem is.

F1 is the only force acting on the vehicle there is no other magical force or energy source.
The direction of F1 is towards the left in my diagram so the vehicle no matter what it will move to the left if at all without involving energy storage.

I drawn all forces in that mechanism 6 of them in total each group of two equal according to Newton's 3'rd law.
F1=F2 F3=F4 and F5=F6
You need to show how F1 different from F2 if you want to claim the vehicle can move.

And I already showed how F2 becomes larger for short bursts due to energy storage released by slip at the front wheel.
There is no alternative explanation and I showed in the video that is exactly what happens. What more can I do ?

Is the same reason a vehicle driving at 30m/s with no wind experiences the same drag as if it drives at 10m/s in a 20m/s head wind again something that to many people get wrong.
As far as I can see is from not understanding that every action has an equal and opposite reaction. I can only imagine what Newton had to deal with.

[IanB]

Notice how there is no-one else responding to your posts?

It is because they are all tired of how you keep advancing nonsensical arguments that are not supported by mathematics, physics or logic, and then you keep asking people to do work to disprove your fallacies.

We don't care that you demonstrate an improper understanding of science, engineering or mathematics. It is not our problem, and it doesn't affect us that you are wrong.

Please stop dragging up the same tired old rubbish, go away, and keep it to yourself.

[electrodacus]

Notice how there is no-one else responding to your posts?

It is because they are all tired of how you keep advancing nonsensical arguments that are not supported by mathematics, physics or logic, and then you keep asking people to do work to disprove your fallacies.

We don't care that you demonstrate an improper understanding of science, engineering or mathematics. It is not our problem, and it doesn't affect us that you are wrong.

Please stop dragging up the same tired old rubbish, go away, and keep it to yourself.

Maybe they starting to question their understanding about the subject.
As mentioned earlier your math doesn't add up. According to you 1x treadmill speed relative to ground equals 2x vehicle speed also relative to ground in the opposite direction.
That is not what is observed in reality.
In fact with just math you can show a 1:1 gear ratio where vehicle moves 2 squares while treadmill is not moving at all. Will that represent reality ? A non moving treadmill powers a 1:1 geared vehicle ? How will that work.



If your theory was adding up and was able to predict what happens I will happy to change my mind and admit I was wrong and also apologize for all the wasted time.
But as of now what I think happens perfectly describes what is observed and is according to accepted physics like Newton's laws and conservation of energy.

[Brumby]

Maybe they starting to question their understanding about the subject.

Absolutely not.

IanB is spot on with this analysis:

Notice how there is no-one else responding to your posts?

It is because they are all tired of how you keep advancing nonsensical arguments that are not supported by mathematics, physics or logic, and then you keep asking people to do work to disprove your fallacies.

We don't care that you demonstrate an improper understanding of science, engineering or mathematics. It is not our problem, and it doesn't affect us that you are wrong.

Please stop dragging up the same tired old rubbish, go away, and keep it to yourself.

[Brumby]

The reason why you have such a significant problem is because you are stubborn, close-minded and have preconceived ideas which prevents you from being open to learning.

Here is a perfect example:

..... as there is no other way for the vehicle to work.

* sigh *

[electrodacus]

The reason why you have such a significant problem is because you are stubborn, close-minded and have preconceived ideas which prevents you from being open to learning.

Here is a perfect example:

..... as there is no other way for the vehicle to work.

* sigh *

Maybe I do not express myself correctly and that should read "there is no other way I can see or was presented that could work"

And main point IanB makes was debunked.
Hes mathematical model can output anything and while consistent with math is not consistent with physics.

As I mentioned earlier his own model can predict the vehicle will move say a random 2 squares to the left with a vehicle that has a 1:1 gear ratio while treadmill will not move at all.
I hope you agree that it will be absurd to claim that vehicle that moved (work was done) was powered by a treadmill that did not move at all.
So yes vehicle can move if you push it but it can not be powered by the treadmill without involving energy storage and stick slip hysteresis.
It is not only that energy storage and stick slip histeresis perfectly explains what happens but it can also be seen happening in the video I provided.

[Nominal Animal]

Electrodacus, I have proven your assertion wrong, and proven a vehicle constructed as I described, works.

I constructed a simple vehicle with a thread spool and a worm gear on a vertical axis, and a pinion gear and driving wheels on a horizontal axis.  I also created a LeoCAD model of the vehicle, so that anyone with Windows, Linux, or Mac, can examine the vehicle in 3D, and build one or a similar one with whatever parts they may have handy.  Just save the attached trike.txt as trike.ldr, and it will open in LeoCAD.  It only uses parts that are available in LeoCAD by default, I believe.

When the spool turns clockwise, the single wheel is the rear wheel.
When the spool turns counterclockwise, the single wheel is the front wheel.

Using strong, non-springy polyester thread (that I normally use for sewing buttons back on), configured either way, pulling the thread off from the spool makes the vehicle move; even when you are pulling the thread in the opposite direction.

Specifically, if the two wheels point left and one wheel right, and the thread comes off the spool counterclockwise and through a hole in the black holder, pulling the thread right makes the vehicle travel left.

Conversely, if the thread comes off the spool clockwise and through a hole in the gray holder, pulling the thread left makes the vehicle travel right.  In other words, this works –– so that pulling the thread makes the vehicle travel in the other direction –– in both directions and configurations; all you need to do is swap the direction the spool turns when you pull the thread off it.

Because this is a worm gear drive, there is absolutely no energy storage.  When you stop pulling the thread, the vehicle stops, because the wheels cannot turn the spool (as a pinion cannot drive a worm, only the worm can drive the pinion).  The spool axis has minimal inertia, too; when you stop pulling the thread, the spool does not unwind on its own.

I can take video of it tomorrow if you insist –– I need to make some kind of a holder for my phone and get better lighting, because my hand-held video was horrible ––, but I'd prefer you yourself build and test a similar vehicle.  It does not need to be exact same, just make the gearing ratio small enough so that there is sufficient stiction for the wheels to drive the vehicle forward.  Note that I had to use a worm gear because I didn't have pinions of different sizes in this set, and because the driving wheels are so much larger than the spool, I'd have needed a large reduction anyway to get the surface speed ratio below 1:1.

I seem to have misplaced my Lego tubs, but I did have one unopened set, Lego Technic 9395 "Pick-up tow truck", that I got as a present from a friend.  This limited the types of gears I had available.  As the set has no chain elements, the best I could do was a thread spool and a single worm-pinion reduction.  I would have used spur gear reduction gearbox if I had suitable gears; alas, this set does not have sufficient gears to do that.  But it does have the worm and pinion.

To turn this into the original treadmill model I described, I would need a Lego chain, two sprockets for it, and replace the spool with a sprocket at the bottom of the trike.  Two idlers for the chain on the trike, so that the chain makes an Ω-shaped loop around the sprocket, would help ensure the chain does not slip.  If you don't want to run the chain vertically, you need to replace the worm and pinion with spur gear reduction instead.  Remember, the reduction has to get *surface speed ratio* below 1:1 for stable running to be possible, but that does *not* limit the ratio of how fast the vehicle travels compared to the thread or treadmill speed (see \$v_c\$ and \$v_t\$ in my earlier post, and how they relate via \$\lambda\$, the surface speed ratio.)
The smaller the ratio, the easier it is to get movement without losing traction.  Remember, *any* movement of the driving wheels moves the vehicle away from the direction you're pulling the thread or the treadmill surface travels, so something like a 1:10 reduction just makes sure you're not tripping on insufficient traction/stiction and such issues.

I do not think anyone should trust my word for it if they truly doubt this is possible (and nothing out of the ordinary, just a trivial mechanism).

This is why I show the CAD model of the exact vehicle I built and verified works as I described –– and Electrodacus claims is impossible ––: so that you can examine it and build it or your own version of it, and prove it yourself.  There is absolutely no trickery here.

[IanB]

Nominal Animal, you have fallen into the trap laid by Electrodacus. He is not interested in truth, he is only interested in persuading other people to spend (waste) their time making things or constructing things in an attempt to prove him wrong. If you spend your time on such fruitless endeavors, you are simply encouraging him. He is a sociopath, whose only interest is in manipulating others. He feels a sense of power and control when he gets other people to do what he wants.

[electrodacus]

Nominal Animal, you have fallen into the trap laid by Electrodacus. He is not interested in truth, he is only interested in persuading other people to spend (waste) their time making things or constructing things in an attempt to prove him wrong. If you spend your time on such fruitless endeavors, you are simply encouraging him. He is a sociopath, whose only interest is in manipulating others. He feels a sense of power and control when he gets other people to do what he wants.

You have not answered me to the last few comments.
I asked if your model can show a vehicle with a 1:1 gear ratio moving 2 squares to the left while the treadmill is not moving at all.
If you agree with that let me know how a non moving treadmill can power the vehicle ?
If you disagree let me know how ?

[Nominal Animal]

Trap or not, we have physical proof now.

Besides, the subject is something that others may wonder about.
It is one thing to argue with math and diagrams and even animations, but a completely different thing to show a model one can build and examine, and build the proof with their own hands.

I hate the idea of others stubling on this thread, and not having any way to determine the truth.  I want to provide a way they can verify for themselves.
Plus, I like to show that when I provide some math, I can also provide physical examples to back it up.  You don't need to trust me, but ignore me at your own peril.

As of right now, it seems that the cheapest way to obtain sufficient parts would be one 42133 set, and one or two 42132 sets.  The first one has the worm and structural parts, the second has drivable wheels (but alas only one of each size) and even a chain (but alas a short one), so two sets of the second are needed for a robust trike model similar to mine, but using a chain.  The sets cost 10€ apiece here right now, so 30€ total.

I won't be spending more effort on this, unless someone wants me to build the treadmill/chain model with build instructions using one 42133 and two 42132 sets (LeoCAD can be used to make Lego build instructions), and is willing to cover the price of the three sets for me, though.  It might be an interesting hands-on device and experiment on why intuition might fail here (thinking that it would be impossible for the vehicle to travel in the opposite direction of the treadmill surface or chain or pulled thread), so might have some educational value.

[IanB]

It is one thing to argue with math and diagrams and even animations, but a completely different thing to show a model one can build and examine, and build the proof with their own hands.

Someone built a model before, but Electrodacus simply rejected it and said it couldn't possibly work without including energy storage in the explanation.