Author Topic: Force multiplier  (Read 33974 times)

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Offline electrodacusTopic starter

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Re: Force multiplier
« Reply #200 on: February 10, 2023, 04:42:57 pm »
Hear Hear  :clap:

My curiosity was triggered such that I decided to build my own vehicles to test the premises. Mind you it is just observational and not actual measurement to proof what is going on. I can't say much about the forces, because I do not have the equipment to measure them. And there in would lie the actual proof.

Glad to hear you where interested enough to decide and do your own experiments. Thanks.

But to me my experiment gave enough proof to believe that what Nominal Animal states is correct.

The attached picture shows the 3 vehicles I build. All have the same base structure, but different size sprockets.
The first one has a 1:1 ratio based on 20 teeth sprockets at both ends.
The second one has a 2:1 or 1:2 ratio (depending on how you look at it) based on a 10 teeth sprocket and a 20 teeth sprocket.
The third one has a 3:1 or 1:3 ratio based on a 10 teeth sprocket and a 30 teeth sprocket.

The gear ratio makes no difference on how the vehicle performs.

For 1:1 there is no longer a define input as both size can be considered input or output so stored energy storage while charged has no way to discharge on just one of the sides thus vehicle can not have a net move in any direction as randomly one set of wheels will slip.
But it is still useful to show that the way belt/chain is connected makes this a locked gear and that is true for all other possible gear ratios.

Correct definitions are 2:1 and 3:1 since when looking at a gear box you need to know which one is input and which one is output and in this application the input is always the small sprocket. 1:2 will mean the large sprocket is the input and a gear ratio of 1/2 = 0.5 
While definition is not so relevant knowing what is the input on a system is important else you will think overunity is possible.

Using manual force on the frame with both set of wheels on the table surface it is easy to move the 1:1 ratio based vehicle, but basically impossible to move the other ones without slipping wheels or sprockets on the axles.

Using a piece of paper like shown in the video of IanB it is impossible to move the vehicle with the 1:1 ratio without either the wheels on the table to slip or the ones on the paper. In this case I call it just dragging things along.

Of course that makes perfect sense because at 1:1 wheels rotate at same speed and forces are the same (no force multiplication)
When using any other gear ratio the wheels will want to spin at different rate and if they can not slip the vehicle is locked.
 

With the other two vehicles it shows the vehicle moving against the direction of the paper with different speeds between the wheels. This can easily be proven by the different distances traveled by the two axles. For this to work the wheels on the paper have the 10 teeth sprockets.

Yes vehicle will move against the direction of input force / paper but the only reason that is possible is energy storage and stick slip hysteresis.
To verify this even with a high speed camera (it will be much easier with a camera at least 120fps if you have one to slow down the video).
But just try to move the paper super slow to see what happens and how force you apply to the paper needs to be so large that the wheels on the paper will need to slip before the vehicle can move powered by the stored energy against the direction of the paper. 


Reversing the vehicle such that the 20 teeth or the 30 teeth sprocket is on the paper, the movement reverses. The vehicle will start to move forward when the paper is dragged forward. There is again a difference in speed of the wheels, which is needed to make it work.

None of this shows any energy storage or slip stick hysteresis to me. With the bigger gear ratio the movement is very smooth.

All it needs is an initial force to overcome the friction and then movement starts. This force is supplied by my hand pushing or pulling the paper.

Here is one of the other main problems and that is considering what is the input and output of the vehicle.
The fact that you put the large sprocket on the moving paper does not mean that vehicle is not the same so all you did was move the input on the table and output on the paper.
So the input in this case is the table and you need to look at the movement of the table surface relative to vehicle then see how vehicle moves relative to that.
You will also be able to see in slow motion that the first wheel that moves is the input so the one with 10 tooth sprocket on the table.

You have a more rigid belt/chain it has both flexibility and a bit of gravitational energy storage as the chain will be lifted when charged but the elastic is likely still the largest contributor.

That initial force is to make the wheel slide so is not about internal forces as it is about dragging the wheel until it slips.
If wheels are all equal the input wheel the one with small sprocket will always be the first to slip and if you can eliminate the slip at input wheel you will see that vehicle no longer moves against the direction of the input force but in the same direction as input force.

It is like saying that a incandescent lamp does not flicker because your brain can not see the fast changes in light intensity and so claiming that lamp works on DC instead of actual AC where light intensity fluctuates 100 or 120 times per second way to fast for our brain to notice.
My claims cannot be disproved with a fast motion of the vehicle and no way to slow down the video to see the charge discharge effect and stick slip hysteresis.
 

But anyone truly understanding Newton's 3'rd law will understand that an object can not move against the direction of the only force applied.
So please if you have a phone or camera that can do some god slow down video take the 2:1 vehicle and do some video in good lighting from the side so that the movement of the wheels can be seen. 

Offline pcprogrammer

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Re: Force multiplier
« Reply #201 on: February 10, 2023, 05:01:14 pm »
I don't have a good camera to do this, and I don't need to be convinced about what is going on. I guess we have to involve the "slow mo guys" to make a proper video about it, but I don't think they will be interested in something like this.

But Nominal Animal was right, there is no convincing you. I just did the experiment to see for myself what happens and I have seen it with my own eyes and don't buy into the energy storage belloni you are trying to sell.

If you really want to proof you are correct, I challenge you to setup a verifiable experiment with measurement equipment and proof that way that there is happening what you claim there is. I don't have equipment for it so I can't do it myself.

Offline electrodacusTopic starter

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Re: Force multiplier
« Reply #202 on: February 10, 2023, 05:15:49 pm »
It's not about internal friction, it is about traction in the wheels.  How about you actually try a 4:1 or higher gear ratio, instead of baseless assertions?

It will make no difference (as I mentioned I used 3:1) and had the same result. The higher the gear ratio the less the vehicle moves with every charge/discharge cycle. At some point is also possible for the belt connecting the wheels to slip wasting the stored energy.
According to your explanation F2 = F1 * 2:1 so F2 = 2*F1 thus why will you need more than this if it was true and at all times?

In reality F2=F1 that increases the F3 = F4 (belt energy storage) and only when input wheel slips the force form the energy stored in the belt adds to F2 and drops very fast as it is converted to vehicle kinetic energy then when it is used up the input wheel sticks again tho this time vehicle is in motion so stick slip happens much faster than first time as I showed in this graph except you can consider the time in ms (not sure what the graph was used for is from google search).

So unless you are superhuman you will not be able to observe stick slip hysteresis and energy storage without a slow moving vehicle and high speed camera.

And I can show you the exact kinematics of why there are no such discharge cycles when the vehicle does not flex.  Yours flexes and behaves badly, because it has such a poor gear ratio, that's all.

My vehicle is not flexing most of the storage is in the rubber belt but even if you make the rubber belt much stiffer all you do is increase the cycle of charge discharge with less energy for each cycle making it harder to see without even higher speed camera and at some point if you reduce the energy storage to much you need to increase the gear ratio significantly else will no longer work/move
Thus your need for larger and larger gear ratios as you reduce the amount of energy storage (elasticity of the elements involved).


If you start your examination from the contact point between the driver wheel and the belt, you have four forces at that point, with the net result a clockwise torque on the axle (assuming belt surface moves left).  If we ignore friction losses in the gearbox, the gear ratio is also the torque ratio.  If your driver wheel turns twice for each driven wheel turn, then the torque at the driver wheel axis is twice the torque on the driven wheel axis.  (See e.g. here.)

The higher the ratio, not only is there more torque, but also the angular and thus linear velocity at which the driver wheel tries to move the vehicle is lower.  That is, with higher gear ratios (using your definition), there is more torque available to move the vehicle forwards.

With lower gear ratios, there is less torque available, and the velocity needed is higher.  When the gear ratio is insufficient, you will see jerkiness, because the wheels –– driven and/or driver –– will slip.  With higher gear ratios (or with wheels with better traction, or with heavier vehicle), there is less and less of wheel slippage, with sufficiently high gear ratios and/or heavy vehicles, the motion is absolutely smooth.

If you change the gearbox so that the driven and driver wheels turn in opposite directions, you just change the sign of \$\lambda\$ as described in my reply #97, noting that \$\lambda\$ is the inverse of the gear ratio as electrodacus prefers it to be defined.

Can you please make a diagram and put the forces on that so we know what net force you are talking about ?
Also we may need to confirm what you consider the driver wheel ?
If this was a proper gearbox with 3 points of contact there will be no slip anywhere and smooth motion even when seen in a slow motion video and even with less than 2:1 gear ratio witch it is plenty and even with a 1:1 gear ratio.

It seems to me you start to admit that this vehicle can not move without wheel slip ?  If so I will consider this progress.

So, you ignored my kinematics equations in reply #97, which shows that there are stable solutions for both same direction and opposite direction, whenever the gear ratio is outside the bad zone?

That with a straight belt, with treadmill surface moving left, the vehicle can move right at basically any speed except at the same speed that the treadmill surface moves left; but the vehicle can only move left faster than the treadmill surface?
That with a twisted belt, with treadmill surface moving left, the vehicle can move right only faster than the threadmill surface moves left; but left at basically any speed except at the same speed the treadmill surface is moving?

Everything I've told you and described to you is mathematically valid and verifiable in both theory and practice.  What you have done, is made assertions and shown one video that fails to perform as I've described, which you have taken as proof that no vehicle can perform as I've described.  Hell, I've even described exactly why your vehicle failed to perform, and instead of verifying it for yourself, you just assert that your vehicle is proof because you don't want to admit you're wrong here.

Are you sure you're not just playing word games and trolling here?  Are you here just to try and convince others that you are right, or are you willing to admit you're wrong and learn?

Testability is a primary aspect in science, and even more so in Physics.  You present one video of one non-performing device as proof, and ignore all examples of devices that are proven to perform.  You even assert that you don't need to modify your device, because the modifications do not matter!  In short, you are refusing to test your understanding.  That is not science, it is religion.

No matter if belt is straight or twisted a vehicle/gearbox with only two points of contact can not do force multiplication. You need 3 points for a gearbox to be called a functional gearbox and be able to do force multiplication.
So the only configuration that will work with two points is twisted belt and 1:1 gear ratio none of the other vehicons can move without slip in the direction of applied force or stick slip hysteresis and energy storage in the opposite direction.

So if you want to prove my theory wrong you will need to show that your vehicle can move with no slip at any of the wheels. (not a little bit of slip or no visible slip but no slip).
If there was no slip allowed the belt or chain will be stretched until it breaks and nothing will move.

Offline fourfathom

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Re: Force multiplier
« Reply #203 on: February 10, 2023, 05:24:01 pm »
I have seen it with my own eyes and don't buy into the energy storage belloni you are trying to sell.

What puzzles me is how this "energy storage" is even supposed to work.  If there is energy to be stored, then there is energy.  This energy can be accumulated and released in bursts (the stick-slip).  Sure, that can happen, we see it all the time.  But this energy can also be used in a continuous mode, without storage and release.  The amount of energy will be unchanged (ignoring losses in both cases), and stick-slip will not increase this energy.

Electronics analogy: PWM vs DC.

The models work with or without stick-slip.  Stick-slip does not increase the available energy.  Stick-slip is an irrelevant distraction.
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Offline PlainName

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Re: Force multiplier
« Reply #204 on: February 10, 2023, 05:26:20 pm »
Quote
I showed in this graph except you can consider the time in ms (not sure what the graph was used for is from google search)

Hey, that's useful. Pick a random graph of something unknown on Google and then it proves whatever you want it to prove. If only other people knew that they could solve no end of problems!
 

Offline electrodacusTopic starter

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Re: Force multiplier
« Reply #205 on: February 10, 2023, 05:30:49 pm »
I don't have a good camera to do this, and I don't need to be convinced about what is going on. I guess we have to involve the "slow mo guys" to make a proper video about it, but I don't think they will be interested in something like this.

But Nominal Animal was right, there is no convincing you. I just did the experiment to see for myself what happens and I have seen it with my own eyes and don't buy into the energy storage belloni you are trying to sell.

If you really want to proof you are correct, I challenge you to setup a verifiable experiment with measurement equipment and proof that way that there is happening what you claim there is. I don't have equipment for it so I can't do it myself.

But what is wrong with my slow motion video ?
Please take say the 2:1 vehicle and while moving the paper as slow as you can watch from the side what happens with the system. It is a way to slow time without access to a slow motion camera.

What will be a good proof for you ?  I can buy two Force newton meter and show forces are equal F1 and F2 ?
You can do that even without the force meters just pull on the paper and you already applied a force and you do not need to know the value of the force but you will see that unless that force is large enough for one of the wheels to slip the vehicle will not move.
To disprove my theory you will need to be able to show that the vehicle can move without any wheel slip. Else it just shows that F1=F2 unless a wheel slips and of course when it starts to slip the force at the wheel starting to slip drops significantly allowing whatever stored energy is available to be converted to kinetic energy.

I can also show that if I restrict the vehicle body by connecting it to ground the force F2 will be 2 * F1 assuming 2:1 gear ratio and there is no slip involved.
There is no such thing as functional gear box without 3 points. No force amplification can happen with 2 points.
After you stretch the belt (energy storage) and input wheel slips you have a system with 3 points as you have now another input energy source (the energy stored in the belt).

To make this even slower motion you can have a generator at the input wheel a battery and a motor at the output wheel.
If you connect generator wires directly to motor it can not work as motor output power can not be larger than input generator power.
But if you connect the generator to battery the battery can be charged then you can connect the battery to motor to move the vehicle forward as you have now an internal energy source not just the external one so you can apply a force between the vehicle body and output wheel.

Offline electrodacusTopic starter

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Re: Force multiplier
« Reply #206 on: February 10, 2023, 05:34:32 pm »
I have seen it with my own eyes and don't buy into the energy storage belloni you are trying to sell.

What puzzles me is how this "energy storage" is even supposed to work.  If there is energy to be stored, then there is energy.  This energy can be accumulated and released in bursts (the stick-slip).  Sure, that can happen, we see it all the time.  But this energy can also be used in a continuous mode, without storage and release.  The amount of energy will be unchanged (ignoring losses in both cases), and stick-slip will not increase this energy.

Electronics analogy: PWM vs DC.

The models work with or without stick-slip.  Stick-slip does not increase the available energy.  Stick-slip is an irrelevant distraction.

Look at example (c) and let me know if that DC-DC boost converter can work.
If you can show me that circuit can boost the V2 to 2*V1 then you won the argument.


Offline pcprogrammer

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Re: Force multiplier
« Reply #207 on: February 10, 2023, 05:35:46 pm »
What puzzles me is how this "energy storage" is even supposed to work.  If there is energy to be stored, then there is energy.  This energy can be accumulated and released in bursts (the stick-slip).  Sure, that can happen, we see it all the time.  But this energy can also be used in a continuous mode, without storage and release.  The amount of energy will be unchanged (ignoring losses in both cases), and stick-slip will not increase this energy.

I don't know. First it was the rubber belt that was doing it, and when replaced with a fairly ridgid chain, it is the chain, and for sure, when I replace it with a bunch of sprockets or a drive shaft it will be the sprockets or the driveshaft having flexibility or what.

The only energy in the experiment is what I put in to it with my hand, and if there is some erratic movement it is also because of my hand. I did make a video with my cell phone, yet it is not very good, but it does show that the 3:1 runs smoother then the 2:1. Has to do with speed I guess.

Offline electrodacusTopic starter

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Re: Force multiplier
« Reply #208 on: February 10, 2023, 05:42:21 pm »
Quote
I showed in this graph except you can consider the time in ms (not sure what the graph was used for is from google search)

Hey, that's useful. Pick a random graph of something unknown on Google and then it proves whatever you want it to prove. If only other people knew that they could solve no end of problems!

It is not something unknown is a graph showing the difference between force needed to overcome static friction and kinetic friction.  Basically the stick slip hysteresis.
Do make a google image search for "stick-slip" and you will find plenty of example relevant as without stick-slip hysteresis there will be no trigger to charge and discharge the energy.

Offline electrodacusTopic starter

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Re: Force multiplier
« Reply #209 on: February 10, 2023, 05:47:21 pm »
I don't know. First it was the rubber belt that was doing it, and when replaced with a fairly ridgid chain, it is the chain, and for sure, when I replace it with a bunch of sprockets or a drive shaft it will be the sprockets or the driveshaft having flexibility or what.

The only energy in the experiment is what I put in to it with my hand, and if there is some erratic movement it is also because of my hand. I did make a video with my cell phone, yet it is not very good, but it does show that the 3:1 runs smoother then the 2:1. Has to do with speed I guess.

There are no materials that have zero elasticity in real world.
Yes the only energy is what you put in with your hand but that energy is first stored (no vehicle motion) then when input wheel slips stored energy is converted to kinetic energy.
Without this combination of storage and then discharge of the storage no vehicle can move against the applied force.

The 3:1 needs to move less so it requires less energy that is why it seems smoother as you put less effort in and also the charge discharge cycles are 50% faster than for 2:1 so even harder to see the non uniform motion due to charge discharge is like it is harder to see a image flicker at 30Hz than at 20Hz

Offline electrodacusTopic starter

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Re: Force multiplier
« Reply #210 on: February 10, 2023, 06:02:20 pm »
Another example of static vs kinetic / sliding friction
Sorry for the low resolution



You can see that applied force F1 equals friction force F2 same as it happens in case (a) and so no different from a solid box like in this above example.
As soon as slip happens the frictional force drops so here is when the stored energy in the belt can now be used inside the vehicle applied between the vehicle body and output wheel to move the vehicle.
If you either remove the slip or energy storage the vehicle can no longer move. But removing energy storage is next to impossible. It can be reduced to the point it no longer works but then you will just select a larger gear ratio and blame the low gear ratio for not working.
Changing the gear ratio will not result in a completely different vehicle you just change the force acting on the belt or chain thus influences the amount of stored energy.
You can have low force on the belt and large displacement or large force and low displacement (stretch) and you can store the same amount of energy by playing with the ratio of force and displacement.
« Last Edit: February 10, 2023, 06:08:48 pm by electrodacus »
 

Offline fourfathom

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Re: Force multiplier
« Reply #211 on: February 10, 2023, 06:35:34 pm »
If you either remove the slip or energy storage the vehicle can no longer move.

Interesting, but false, assertion.  You constantly return to this claim, but you have provided no plausible proof or demonstration.  Others have shown (in many ways) that energy storage is not necessary.

Again, explain why this energy cannot be used without storage.  Friction / stiction / stretch are minor factors in a properly designed "vehicle", and irrelevant to this discussion.  They affect the efficiency, but not the fundamental principle.
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Offline electrodacusTopic starter

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Re: Force multiplier
« Reply #212 on: February 10, 2023, 06:50:47 pm »
If you either remove the slip or energy storage the vehicle can no longer move.

Interesting, but false, assertion.  You constantly return to this claim, but you have provided no plausible proof or demonstration.  Others have shown (in many ways) that energy storage is not necessary.

Again, explain why this energy cannot be used without storage.  Friction / stiction / stretch are minor factors in a properly designed "vehicle", and irrelevant to this discussion.  They affect the efficiency, but not the fundamental principle.

A "vehicle" has an internal motor/engine and energy source.
While we call this a "vehicle" it is a very special case an nothing more than a locked gearbox.
Due to energy storage and stick slip hysteresis it has a very particular and no intuitive behaviour and that is the ability to move against the direction of external applied force.

In a "normal vehicle" with an internal engine or motor the force is applied between the vehicle body and output wheel  so if a flexible belt is used there you have the stretch of the belt during initial acceleration but then stretch remains constant is not fluctuating between stretch and unstretch multiple times per second as it happens in this vehicle where belt is used as an energy storage device to accelerate the vehicle athens or even hundreds of times per second.

There are a few facts that you do not understand:

1) Every action has an equal and opposite reaction.
2) A device (gearbox) can not do force multiplication with only two points of contact for that 3 points are needed.
3) An externally only powered device can not move against the direction of applied force.  (when have you ever pushed a box and the box pushed you back further than you pushed the box). And if that ever happened to you it was likely a very elastic box and you were thrown back when you lost traction by the elastic energy that you stored in pushing the super elastic box.

Offline cbutlera

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Re: Force multiplier
« Reply #213 on: February 10, 2023, 07:07:10 pm »
...
The video/video's is not an explanation is a proof that my explanation is correct.
It shows the vehicle in case (a) being dragged. That means a large F1 force is applied so large that it can drag the vehicle in the direction F1 is pointing and there is no wheel rotation so basically it acts as a solid object.
Relation between F1 and F2 is that F2 = F1 except for the short duration when vehicle is accelerate from zero to a constant speed when F1 = F2 + (m*a)
I will love you try and find an alternative explanation that is consistent with what is observed in that video first 15 seconds with the last few seconds showing that vehicle is not faked and that wheels can rotate if the input wheels (the ones on the right) are allowed to slip.
...

I think that I may be making some progress here, but rather than this specific example, I’m trying to understand the analytical method that you are advocating.  For me that is much more useful.  I have made a list of the key points that I have picked up from what you have written. Am I on the right track here?  If you do see any errors, could you correct the text as necessary.

1) Intuition plays a key role in classical mechanics.

2) Before making any calculations, it is vital that the analyst chooses the correct frame of reference in which to perform those calculations.  This can only be done through intuition, built up from years of experience.  Inexperienced analysts can easily get this step wrong and choose the wrong frame of reference.  In which case any conclusions that they draw from subsequent mathematical analysis will be invalid.

3) There are two classes of frames of reference, which are the accelerating and non-accelerating frames of reference.

4) In an accelerating frame of reference, objects within that frame obey Newton’s second law of motion.

5) In a non-accelerating frame of reference, Newton’s second law is not relevant, because nothing is accelerating.  In this case, Newton’s third law will apply to every object in that system, so every object in the system will be subject to a net zero balance of forces.  In the case of two forces acting on an object they must necessarily be equal and opposite.  This is what Newton meant by stating "To every action, there is always opposed an equal reaction”.

6) Some mechanical systems can alternate between being in accelerating and non-accelerating frames of reference.  The analyst needs to take great care here to allocate the correct frame of reference to each moment in time.  Inexperienced and even many experienced analysts can get this wrong, and is one of the most difficult skills to master.
 

Offline PlainName

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Re: Force multiplier
« Reply #214 on: February 10, 2023, 07:33:41 pm »
What will be a good proof for you ?  I can buy two Force newton meter and show forces are equal F1 and F2 ?

Yes, get those meters and show that F1 and F2 are equal.
« Last Edit: February 10, 2023, 07:36:15 pm by PlainName »
 

Offline electrodacusTopic starter

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Re: Force multiplier
« Reply #215 on: February 10, 2023, 11:54:19 pm »
I think that I may be making some progress here, but rather than this specific example, I’m trying to understand the analytical method that you are advocating.  For me that is much more useful.  I have made a list of the key points that I have picked up from what you have written. Am I on the right track here?  If you do see any errors, could you correct the text as necessary.

1) Intuition plays a key role in classical mechanics.

I do not know if I will agree with that. There is not much if anything that was not studied in classical mechanics. Sometimes "intuition" seems to be wrong.
For example using kinematics only and not considering forces will not provide the correct answer.
To me it seems that people always imagine that the force is applied between vehicle body and input wheel not as it is the case between the input wheel and the ground.
The only time the force is applied between the vehicle body and output wheel is when stored energy is discharged in that case the vehicle is powered from inside and not form the exterior.


2) Before making any calculations, it is vital that the analyst chooses the correct frame of reference in which to perform those calculations.  This can only be done through intuition, built up from years of experience.  Inexperienced analysts can easily get this step wrong and choose the wrong frame of reference.  In which case any conclusions that they draw from subsequent mathematical analysis will be invalid.

Again not sure we have the same definition for intuition.
Result will be the same independent of the reference frame chosen.


3) There are two classes of frames of reference, which are the accelerating and non-accelerating frames of reference.

For this particular example you can only have acceleration if either input or output wheels slip so unless that happens there will be no acceleration.
The applied force F1 needs to be large enough for slip to happen else if that is less nothing will happen other than belt will be stretched the input wheel will rotate correspondingly with the amount of stretch but vehicle body will not move relative to ground.

If output wheel (left one) slips first then vehicle will be accelerated to the left and F1 the applied force will be F1 = F2 + m*a so sum of 3'rd and 2'nd law.
If input wheel slips (right one) (this is what happens if you have the same type of wheels and and material since the input wheel already rotates and it will slip more easy) the you have F2 = F1 + m*a and F2 can be larger due to belt applying a force inside the vehicle between the vehicle body and output wheel and this force is possible because of stored energy.
As you see from this equations the gear ratio is not involved unless you look at the amount of stored energy as that will depend on the gear ratio.   
   

4) In an accelerating frame of reference, objects within that frame obey Newton’s second law of motion.

As I mentioned 2'nd law is involved only if you allow wheel slip. And the direction the vehicle is accelerated depends on which wheel slips.
If the vehicle worked the way you think it works there will be no wheel slip but that is not the case in any experimental test where vehicle moves.

5) In a non-accelerating frame of reference, Newton’s second law is not relevant, because nothing is accelerating.  In this case, Newton’s third law will apply to every object in that system, so every object in the system will be subject to a net zero balance of forces.  In the case of two forces acting on an object they must necessarily be equal and opposite.  This is what Newton meant by stating "To every action, there is always opposed an equal reaction”.

That is not quite true.  It is true that net forces for this particular problem is zero in an non accelerating reference frame.
But if you have a proper (working) gearbox that means 3 points of contact so vehicle body connected to ground. Then the applied F1 will be between vehicle body and input wheel and the F2 will be between vehicle body and output wheel and at 2:1 gear ratio the F2 = 2*F1 and that will be the case in an non accelerating frame of reference.
If not convinced by this think about a balance with fulcrum the third point offset as in image below.
Nothing will need to move for the input force to be smaller than output force and Newton's 3'rd law works here as two separate loops with F1 input force having a pair at the fulcrum and the other pair F2 output also relative to fulcrum.
But example a has no 3'rd point the fulcrum equivalent so with that missing input and output force can only be equal.


6) Some mechanical systems can alternate between being in accelerating and non-accelerating frames of reference.  The analyst needs to take great care here to allocate the correct frame of reference to each moment in time.  Inexperienced and even many experienced analysts can get this wrong, and is one of the most difficult skills to master.

Yes that is the case here when vehicle moves to the right against the applied force as the vehicle will accelerate in burst many times per second so fast that it looks like smooth motion to the slow human brain.
Maybe it is a difficult skill but as soon as you see a device moving in the opposite direction of applied force you will know that some other energy source is present like in this case a small energy storage device.
Because you know from experience and Newton's 3'rd law that for every action there is an equal and opposite reaction so you can not have an unpowered item like this vehicle pushing with higher force F2 against the applied F1 as that will also violate the energy conservation.
The energy conservation is not violated in this case only because energy is stored so treadmill moves say 1cm while vehicle is not moving at all but this 1cm and the F1 was stored as elastic energy in the rubber band then in the next moment this stored energy could be converted in kinetic energy in the opposite direction and if there was no friction with just this initial energy the vehicle can maintain forever the gained kinetic energy but since there is friction the cycle of charge discharge needs to repeat all the time to maintain an average speed. Speed of this vehicle is not constant but it is not possible for humans to detect that without faster more sensitive measurement equipment.

Offline fourfathom

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Re: Force multiplier
« Reply #216 on: February 11, 2023, 12:30:52 am »
some other energy source is present like in this case a small energy storage device.

This is *NOT* an energy source.
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Offline electrodacusTopic starter

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Re: Force multiplier
« Reply #217 on: February 11, 2023, 12:35:37 am »
some other energy source is present like in this case a small energy storage device.

This is *NOT* an energy source.

It is a charged energy storage device. How will you call that if not an energy source ?

Offline cbutlera

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Re: Force multiplier
« Reply #218 on: February 11, 2023, 01:53:24 am »
Thanks for that detailed response, I think I am getting closer to understanding your method of analysis. I was trying to make generalised statements that could be applied to any mechanical system rather than just to this specific example.

I think that I may be making some progress here, but rather than this specific example, I’m trying to understand the analytical method that you are advocating.  For me that is much more useful.  I have made a list of the key points that I have picked up from what you have written. Am I on the right track here?  If you do see any errors, could you correct the text as necessary.

1) Intuition plays a key role in classical mechanics.

I do not know if I will agree with that. There is not much if anything that was not studied in classical mechanics. Sometimes "intuition" seems to be wrong.
For example using kinematics only and not considering forces will not provide the correct answer.
To me it seems that people always imagine that the force is applied between vehicle body and input wheel not as it is the case between the input wheel and the ground.
The only time the force is applied between the vehicle body and output wheel is when stored energy is discharged in that case the vehicle is powered from inside and not form the exterior.


2) Before making any calculations, it is vital that the analyst chooses the correct frame of reference in which to perform those calculations.  This can only be done through intuition, built up from years of experience.  Inexperienced analysts can easily get this step wrong and choose the wrong frame of reference.  In which case any conclusions that they draw from subsequent mathematical analysis will be invalid.

Again not sure we have the same definition for intuition.
Result will be the same independent of the reference frame chosen.

Perhaps I should have written that it is vital to choose the correct class of reference frame.  In other words, for an unspecified mechanical system, not one of the examples we have been considering, is the analyst free to choose an accelerating or a non-accelerating frame of reference in which to perform his analysis.  With the same result being obtained either way?

For instance would it be appropriate to analyse an accelerating car using a non-accelerating frame of reference?

Quote
3) There are two classes of frames of reference, which are the accelerating and non-accelerating frames of reference.

For this particular example you can only have acceleration if either input or output wheels slip so unless that happens there will be no acceleration.
The applied force F1 needs to be large enough for slip to happen else if that is less nothing will happen other than belt will be stretched the input wheel will rotate correspondingly with the amount of stretch but vehicle body will not move relative to ground.

If output wheel (left one) slips first then vehicle will be accelerated to the left and F1 the applied force will be F1 = F2 + m*a so sum of 3'rd and 2'nd law.
If input wheel slips (right one) (this is what happens if you have the same type of wheels and and material since the input wheel already rotates and it will slip more easy) the you have F2 = F1 + m*a and F2 can be larger due to belt applying a force inside the vehicle between the vehicle body and output wheel and this force is possible because of stored energy.
As you see from this equations the gear ratio is not involved unless you look at the amount of stored energy as that will depend on the gear ratio.   
   

4) In an accelerating frame of reference, objects within that frame obey Newton’s second law of motion.

As I mentioned 2'nd law is involved only if you allow wheel slip. And the direction the vehicle is accelerated depends on which wheel slips.
If the vehicle worked the way you think it works there will be no wheel slip but that is not the case in any experimental test where vehicle moves.


As a general statement, but not with reference to the current examples, is my statement 4) correct in your view?

So using the accelerating car example, would you agree that an accelerating frame of reference must be used, so that Newton’s second law can be applied?

Quote
5) In a non-accelerating frame of reference, Newton’s second law is not relevant, because nothing is accelerating.  In this case, Newton’s third law will apply to every object in that system, so every object in the system will be subject to a net zero balance of forces.  In the case of two forces acting on an object they must necessarily be equal and opposite.  This is what Newton meant by stating "To every action, there is always opposed an equal reaction”.

That is not quite true.  It is true that net forces for this particular problem is zero in an non accelerating reference frame.
But if you have a proper (working) gearbox that means 3 points of contact so vehicle body connected to ground. Then the applied F1 will be between vehicle body and input wheel and the F2 will be between vehicle body and output wheel and at 2:1 gear ratio the F2 = 2*F1 and that will be the case in an non accelerating frame of reference.
If not convinced by this think about a balance with fulcrum the third point offset as in image below.
Nothing will need to move for the input force to be smaller than output force and Newton's 3'rd law works here as two separate loops with F1 input force having a pair at the fulcrum and the other pair F2 output also relative to fulcrum.
But example a has no 3'rd point the fulcrum equivalent so with that missing input and output force can only be equal.


I can see that now.  Your lever and fulcum example clarifies your understanding of Newton's third law to me quite well.

Would you agree that my statement 5) is always true in a non-accelerating frame of reference? Again, as a general statement about non-accelerating frames of reference, not just with regard to this specific example.

Quote
6) Some mechanical systems can alternate between being in accelerating and non-accelerating frames of reference.  The analyst needs to take great care here to allocate the correct frame of reference to each moment in time.  Inexperienced and even many experienced analysts can get this wrong, and is one of the most difficult skills to master.

Yes that is the case here when vehicle moves to the right against the applied force as the vehicle will accelerate in burst many times per second so fast that it looks like smooth motion to the slow human brain.
Maybe it is a difficult skill but as soon as you see a device moving in the opposite direction of applied force you will know that some other energy source is present like in this case a small energy storage device.
Because you know from experience and Newton's 3'rd law that for every action there is an equal and opposite reaction so you can not have an unpowered item like this vehicle pushing with higher force F2 against the applied F1 as that will also violate the energy conservation.
The energy conservation is not violated in this case only because energy is stored so treadmill moves say 1cm while vehicle is not moving at all but this 1cm and the F1 was stored as elastic energy in the rubber band then in the next moment this stored energy could be converted in kinetic energy in the opposite direction and if there was no friction with just this initial energy the vehicle can maintain forever the gained kinetic energy but since there is friction the cycle of charge discharge needs to repeat all the time to maintain an average speed. Speed of this vehicle is not constant but it is not possible for humans to detect that without faster more sensitive measurement equipment.
 

Offline Nominal Animal

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Re: Force multiplier
« Reply #219 on: February 11, 2023, 02:49:14 am »
The gear ratio makes no difference on how the vehicle performs.
I showed you in reply #97 in clear math that it does.  Others have tested it, and agree it does.  Yet, you insist on asserting that it does not, without any explanation –– except that your single video with an extremely bad choice of a gear ratio somehow proves to you it doesn't.

That is bullshit.  We have shown you a number of vehicles that prove the gear ratio makes a major difference in how the vehicle performs.  I've shown the exact math, derived from kinematics, which is the simplest form of mechanical analysis, showing it does.  Yet, you insist on claiming it doesn't matter, why?  Is it because you know it does matter, and that demolishes your argument, and you're not interested in learning, and are here just to try and "win" some kind of word or trolling game?

Gearing ratio 1:1 is a singular point in the math (leads to division by zero) – the vehicle will not work in the cases we're examining here at all then –, and all ratios close to 1:1 are extremely sensitive to wheel-surface friction, inducing all kinds of flexing in the mechanism (because the induced velocities are large compared to the torque available, leading to parts twisting and flexing), leading to incorrect interpretation of what is happening.  Ratios far away provide more torque with smaller steady-state velocities, which does not stress the mechanism as much (so no flexing or twisting even with lightweight plastic parts), and show the movement is smooth.

Is the reason you refuse to admit this, that you know it proves your belief and assertions incorrect, and you just don't want to admit that –– because it would stop this language game you like to play here at EEVblog forums?

I don't care about your games one way or another, but I do care about the fact that other people, especially youngsters lacking the education yet, can find these threads by doing a web search using suitable search terms, and may be swayed by your convincing-sounding writing, even though there is no logic, science, or rational thought behind your language.  It's exactly the same mechanism charismatic movements and cult leaders gather following, by manipulating others.  And I hate that, because it wastes those peoples' time and honest efforts; those youngsters doing the web searches are really trying to learn, and you're deliberately fucking that up for them.  I despise your behaviour here for that reason, just like I despise people who smear human excrement on the walls, even if they do it to a building I myself will never visit.

All my efforts in this thread are not for you, electrodacus, even though I don't consider you an enemy, and only want you too to learn.  My efforts have been to minimise the long-term negative efforts your language games here are making to others' efforts to learn.  Regardless of what do you here to "win" or bolster your ego, you need to remember we're spending our time and effort in this thread, only to minimize the negative effects of your illogical and irrational babble has on others reading these texts.  It is quite sad, really.
 

Offline electrodacusTopic starter

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Re: Force multiplier
« Reply #220 on: February 11, 2023, 02:51:31 am »

I can see that now.  Your lever and fulcum example clarifies your understanding of Newton's third law to me quite well.

Would you agree that my statement 5) is always true in a non-accelerating frame of reference? Again, as a general statement about non-accelerating frames of reference, not just with regard to this specific example.

Can you clarify where your think understanding of Newton's third law differs from mine ?

Do you understand that example (a) (actually all but I'm most interested in example (a)) will be equivalent with the above diagram if the fulcrum was not in contact with ground so could not transfer any force to ground (floating fulcrum) ?
To make the case (a) equivalent with the above the vehicle body (blue color part) will need to be connected rigidly to ground.

There is no good analogy to make because gravity is involved here and fulcrum not touching the ground (floating fulcrum) will be ridiculous but that is what device in case (a) is a gearbox with floating body thus is incapable of force multiplication same as this with floating fulcrum can not do force multiplication.


Regarding accelerating vs non accelerating reference frames.
For case (a) it is irrelevant as you have a locked gearbox that can not move so for any force F1 the F2 will be equal and opposite.
There is no specification of wheel friction or material elasticity in case (a)
But if you consider a real case instead of the theoretical case then there is both elasticity (no material is perfectly rigid) and there is also friction.
The other important aspect in a real setup is the fact that there is a stationary friction coefficient and a kinetic one and they are different.

Because of elasticity when treadmill is started / turn ON there will be movement but because the mechanism (vehicle/gearbox) acts as a solid object unless the treadmill can provide a force large enough to exceed the stationary friction the input wheel will rotate a bit stretching the belt and then stop in that condition will net force on vehicle always zero.
The instant the force F1 exceeds stationary friction the net force will no longer be zero but the direction of this net force and the source will depend on which wheel slips.
If is the output wheel that slips then net force will point to the left and be provided by treadmill and if the input wheel slips the net force will point to the right and be provided by the stored elastic energy.

I think this is as good and complete example of what happens and also demonstrated in real experiments.

It seems to me that your explanation for vehicle moving to the right is force multiplication from a functional gearbox.  In order for this to be the explanation you will need to prove me that a gearbox with only two points of contact can do force multiplication.
There is to my knowledge no force multiplication device that can work with just two points of contact (the input and the output) and no third point the "body/case" against which it can reference the input and output.

Offline electrodacusTopic starter

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Re: Force multiplier
« Reply #221 on: February 11, 2023, 03:00:29 am »
I don't care about your games one way or another, but I do care about the fact that other people, especially youngsters lacking the education yet, can find these threads by doing a web search using suitable search terms, and may be swayed by your convincing-sounding writing, even though there is no logic, science, or rational thought behind your language.  It's exactly the same mechanism charismatic movements and cult leaders gather following, by manipulating others.  And I hate that, because it wastes those peoples' time and honest efforts; those youngsters doing the web searches are really trying to learn, and you're deliberately fucking that up for them.  I despise your behaviour here for that reason, just like I despise people who smear human excrement on the walls, even if they do it to a building I myself will never visit.

All my efforts in this thread are not for you, electrodacus, even though I don't consider you an enemy, and only want you too to learn.  My efforts have been to minimise the long-term negative efforts your language games here are making to others' efforts to learn.  Regardless of what do you here to "win" or bolster your ego, you need to remember we're spending our time and effort in this thread, only to minimize the negative effects of your illogical and irrational babble has on others reading these texts.  It is quite sad, really.

I can echo exactly what you have mentioned here except for the part about cults and human excrements.
I just think there is some brain limitation that makes you unable to understand the correct explanation of how this sort of vehicle works.

The title of this thread is force multiplier as that is your explanation of how this vehicle could move to the right.
My simplest debunk is that you can not have force multiplication while having just two points of contact and that will require 3 points.

So you either disagree that 3 points are needed and then provide a real world device that I can buy that will do that (like a force multiplier wrench) or you specify what is the third point since I do not see one in diagram (a).

Offline IanB

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Re: Force multiplier
« Reply #222 on: February 11, 2023, 03:10:13 am »
I just think there is some brain limitation that makes you unable to understand the correct explanation of how this sort of vehicle works.

Anyone reading this thread now or in the future needs to understand that the "you" highlighted in the above sentence refers to the whole world of physicists and engineers other than electrodacus. That somehow electrodacus has a unique understanding that the whole rest of the world lacks, and that the whole rest of the world has some kind of brain limitation that prevents them understanding what only electrodacus can see.

Anyone reading this thread then has to consider how likely is it that the above situation is true?
 

Offline electrodacusTopic starter

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Re: Force multiplier
« Reply #223 on: February 11, 2023, 03:19:20 am »
I just think there is some brain limitation that makes you unable to understand the correct explanation of how this sort of vehicle works.

Anyone reading this thread now or in the future needs to understand that the "you" highlighted in the above sentence refers to the whole world of physicists and engineers other than electrodacus. That somehow electrodacus has a unique understanding that the whole rest of the world lacks, and that the whole rest of the world has some kind of brain limitation that prevents them understanding what only electrodacus can see.

Anyone reading this thread then has to consider how likely is it that the above situation is true?

No not the whole world just a very limited number that I interacted with.
Keep in mind that we (all humans) have a lot of quite significant brain limitations and we see thing that are not there or do not see things that are there.

Here is a good example of what I'm saying.
A and B squares (the background) are the exact same shade on gray



Drawing a line makes it evident
« Last Edit: February 11, 2023, 03:26:18 am by electrodacus »
 

Offline fourfathom

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Re: Force multiplier
« Reply #224 on: February 11, 2023, 03:57:47 am »
some other energy source is present like in this case a small energy storage device.

This is *NOT* an energy source.

It is a charged energy storage device. How will you call that if not an energy source ?

And what is the source of this stored energy?  Please explain why this source cannot be used directly, without the intermediate energy storage / discharge (stick / slip).  This is a critical point which you persist in ignoring.  This sounds like a religious axiom for you: unprovable and must be accepted on faith.
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