Author Topic: Newton's third law problem.  (Read 26692 times)

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Offline electrodacusTopic starter

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Re: Newton's third law problem.
« Reply #100 on: November 24, 2022, 04:03:56 pm »
Harsh dude 8)

Maybe these wikis will help OP:

https://en.m.wikipedia.org/wiki/Fluid_dynamics

https://en.m.wikipedia.org/wiki/Radiation_pressure

https://en.m.wikipedia.org/wiki/Yarkovsky_effect

Quote from your first link:
"Fluids are composed of molecules that collide with one another and solid objects."

Online PlainName

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Re: Newton's third law problem.
« Reply #101 on: November 24, 2022, 04:40:08 pm »
Quote
The only way the vehicle is powered by wind is by air particles colliding and providing their kinetic energy to vehicle.

Wrong. You'll never get how it works whilst you persist on thinking this.

Please enlighten me.
How do air particle transfer energy to vehicle if not through collision ?

And as you claim to know how it works please also provide the equation describing the amount of wind power available to vehicle.

In the previous threads I tried stepping you though it very simply (and it was tough keeping you ontrack and not racing ahead down distraction rabbit holes), but once you saw where it was going you disappeared. Why would this time be any different?

Nevertheless, your problem is starting with the wind power first and then trying to apply that to obvious stuff. Forget where the power comes from for the moment and look at how it's actually working, then figure how to power it.

First, you have a propeller which is pushing the vehicle along. We know that works because jets take off - if the prop is turning then it is pushing the vehicle even if ever so slightly. It's pushing against the prevalent wind, and you even agreed earlier in this thread that this kind of thing is additive. If the prop can push a 5m/s and the wind is 10m/s then the vehicle will go at 15m/s.

That's uncontestable physics and fact, but feel free to disagree if you dare.

So, what we're stuck for is the power that drives the prop. We know it is coming from the wheels (that is, the wheels drive the prop and not vice versa), and the wheels get it from the vehicle being pushed by the wind. But... the vehicle is going faster than the wind so what does the wind push on? It is the backwash from the propeller - remember the 5m/s plus whatever the prevalent wind is, which is this case is maybe -2m/s, so a small forward movement for a larger backwards jet.

Hang on, isn't this free energy or something? No, because of drag, which will require more power to overcome, and loss of power as more is extracted. Just think about it for a moment: the wind is pushing the vehicle (yes, due to air bouncing off it) at almost wind speed and there is no drag. All that's required is for the prop to turn however, slowly, and produce a minute amount of thrust which will increase the vehicle speed a tiny amount and it's game on, but go a bit faster and you need more power to overcome the drag and similar losses. But if you have drag you are going faster than the wind. Can the wheels extra that tiny amount of power without slowing the vehicle? That's where leverage, size of prop and angle of blades come in.

Equations? Dunno. I'm not clever enough to work one out that you would reject or ignore anyway, and I doubt there is one on t'web to copy like you do. But I can point to video of the actual vehicle and many models working continuously and without any energy storage facilities.

Edit: forgot to point out that the wind power increases as the vehicle slows. There is far more power available than is consumed to push the vehicle forward - it's just that there is nothing to suck it up normally so the vehicle accelerates. At wind speed, there is 0 power pushing the car forward, but all the power of the wind is still available if you can work out how to access it. That's where the wheels are getting apparently free power from.
« Last Edit: November 24, 2022, 04:43:58 pm by PlainName »
 

Online Nominal Animal

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Re: Newton's third law problem.
« Reply #102 on: November 24, 2022, 05:16:14 pm »
How do air particle transfer energy to vehicle if not through collision ?
Modeling the macro-scale properties of compressible fluids as colliding solid particles is just not tenable.  I know, because my proper field is molecular dynamics simulations.

In particular, a molecule does not have a well-determined surface at all; there is just a "shroud" of delocalized outermost electrons, and we assign an arbitrary electron density as the "surface".

Molecule interactions can be split into four categories: Pauli exclusion principle, electrostatic interactions between permanent charges (ions and multipoles), induction/polarization ("Debye force"), and London dispersion.  "Collision" does not even begin to describe all these.  At the molecular scale, even defining "a collision" is difficult, as there is no strict distance at which interactions start or stop: they interact, exchanging energy.  Not just "kinetic" energy –– as in the movement of the center of mass of the molecule ––, but also energy related to internal excitation states (often part of the "thermal" energy of that molecule).

When we are dealing with air, the key physics field to consider is aerodynamics.  In particular, most useful effects are related to changes in pressure, not "collisions".  However, the case where the vehicle is in connection to ground, differs a lot from aeroplanes, because the key velocity is not airspeed, i.e vehicle velocity with respect to surrounding air, but groundspeed, because the vehicle uses the contact with ground for acceleration.

And as you claim to know how it works please also provide the equation describing the amount of wind power available to vehicle.
It depends on the vehicle.  For a ground vehicle, what matters is that it depends not on the vehicle airspeed (speed of vehicle relative to the surrounding air), but on the velocity and pressure of air with respect to ground.  This is because the vehicle spends its energy in an effort to accelerate with respect to ground, not with respect to wind; to compensate for the drag and friction (i.e., losses) the vehicle experiences.

Yes, aeroplanes and ground vehicles differ significantly in this.

An easy to understand vehicle that can extract energy from air when their relative speeds are the same, is a cart with a vertical axis airfoil wind turbine.  The airfoils do not "catch" wind, they act like aeroplane wings, generating torque from the pressure differential on different sides of the blade.  During any motion of the vehicle, the VAAWT is rotating.  When the vehicle travels downwind at the same speed as the wind, the blades of the VAAWT can still extract energy from the wind in all phases except when the blade is in its extremum position with respect to the travel direction.  It is obvious, since the blade is moving wirth respect to air surrounding it.  Because of the pressure differential principle, the direction of the wind is easily compensated by changing the blade orientation/attack angle.  The only limiting factor is how efficient you can make your vehicle, how small you can make the losses in its mechanisms.
 

Offline electrodacusTopic starter

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Re: Newton's third law problem.
« Reply #103 on: November 24, 2022, 05:22:32 pm »
Thanks for taking the time to replay.
I also need to mention for others that below discussion is about direct downwind since this thread was about the upwind mainly.


In the previous threads I tried stepping you though it very simply (and it was tough keeping you ontrack and not racing ahead down distraction rabbit holes), but once you saw where it was going you disappeared. Why would this time be any different?

Nevertheless, your problem is starting with the wind power first and then trying to apply that to obvious stuff. Forget where the power comes from for the moment and look at how it's actually working, then figure how to power it.

I think that is the logical place to start from figuring out the amount of wind power available then decide what you can do with that.
If you forget about that you will think that you can do anything.



First, you have a propeller which is pushing the vehicle along. We know that works because jets take off - if the prop is turning then it is pushing the vehicle even if ever so slightly. It's pushing against the prevalent wind, and you even agreed earlier in this thread that this kind of thing is additive. If the prop can push a 5m/s and the wind is 10m/s then the vehicle will go at 15m/s.

That's uncontestable physics and fact, but feel free to disagree if you dare.

If by pushing you mean accelerating then you need to apply power to the propeller.
So if the starting point is that vehicle is at 15m/s driving in the same direction as wind witch is at just 10m/s and there is zero friction so ideal case the vehicle will be able to maintain that speed but will be unable to accelerate if there is no stored energy other than the vehicle kinetic energy.
   


So, what we're stuck for is the power that drives the prop. We know it is coming from the wheels (that is, the wheels drive the prop and not vice versa), and the wheels get it from the vehicle being pushed by the wind. But... the vehicle is going faster than the wind so what does the wind push on? It is the backwash from the propeller - remember the 5m/s plus whatever the prevalent wind is, which is this case is maybe -2m/s, so a small forward movement for a larger backwards jet.

Getting 100W as an example from the wheels means you are decelerating the vehicle by that exact amount and so if you provide that to an 100% efficient propeller you will get back 100W worth of acceleration thus you end up with nothing.
In a real vehicle doing such a thing will result in deceleration as for 100W taken at the wheel you will be able at most to say provide 80W worth of thrust thus you are decelerating at a 20W rate (slowing down).
 

Hang on, isn't this free energy or something? No, because of drag, which will require more power to overcome, and loss of power as more is extracted. Just think about it for a moment: the wind is pushing the vehicle (yes, due to air bouncing off it) at almost wind speed and there is no drag. All that's required is for the prop to turn however, slowly, and produce a minute amount of thrust which will increase the vehicle speed a tiny amount and it's game on, but go a bit faster and you need more power to overcome the drag and similar losses. But if you have drag you are going faster than the wind. Can the wheels extra that tiny amount of power without slowing the vehicle? That's where leverage, size of prop and angle of blades come in.

Too much nonsense to be able to provide a constructive replay.

Equations? Dunno. I'm not clever enough to work one out that you would reject or ignore anyway, and I doubt there is one on t'web to copy like you do. But I can point to video of the actual vehicle and many models working continuously and without any energy storage facilities.

Edit: forgot to point out that the wind power increases as the vehicle slows. There is far more power available than is consumed to push the vehicle forward - it's just that there is nothing to suck it up normally so the vehicle accelerates. At wind speed, there is 0 power pushing the car forward, but all the power of the wind is still available if you can work out how to access it. That's where the wheels are getting apparently free power from.

There is no problem copying an equation from either the web or your mind if it is the right one for the subject.
There is no video showing a direct downwind vehicle driving continuously. As far as I know large scale model is just one the Blackbird  and all the treadmill models have a very limited space before they fall out on the other side.
But what you can do is take a video from the side on one of the treadmill models and you will see the rate of acceleration decreasing meaning it at some point get to zero and start decelerating.

"Free power"  :) There is no such thing.

Online Nominal Animal

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Re: Newton's third law problem.
« Reply #104 on: November 24, 2022, 05:33:35 pm »
Direct upwind is trivial to demonstrate: just put an efficient horizontal turbine on a cart, and use a very low gearing to the wheels (i.e. turbine turns many tens of times per one rotation of the wheels).  Make it a VAWT and the cart will move regardless of the wind direction.

This matches my Lego trike I demonstrated earlier, and whose exact behaviour I described mathematically (in terms of velocities or displacements, and gear ratio); instead of wind, it used a spool of thread, or a Lego chain/track.

If one were to build a model where the ground wheel is actually a pulley with a wire looped around it and fixed to ground at both ends, it shows that no slip is required at all for it to function as described.  Indeed, if the wire is looped many times around the pulley, and fixed to the pulley at the midpoint, then no slip is even possible if one uses e.g. thin steel cable.
 

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electrodacus' problem with Physics.
« Reply #105 on: November 24, 2022, 05:45:46 pm »
Fixed the topic for you.
 

Offline electrodacusTopic starter

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Re: Newton's third law problem.
« Reply #106 on: November 24, 2022, 05:50:43 pm »
Modeling the macro-scale properties of compressible fluids as colliding solid particles is just not tenable.  I know, because my proper field is molecular dynamics simulations.

That is because of our limited compute capability. That will not change the fact that air molecules collide with the vehicle body and that is how energy is transferred.
The equation we have and I provided many times is doing a great approximation of the wind power available without calculating energy provided by each air molecule.  We just select an air density typical 1.2kg/m3 and the area and coefficient of drag of the solid surface it interacts with.


It depends on the vehicle.  For a ground vehicle, what matters is that it depends not on the vehicle airspeed (speed of vehicle relative to the surrounding air), but on the velocity and pressure of air with respect to ground.  This is because the vehicle spends its energy in an effort to accelerate with respect to ground, not with respect to wind; to compensate for the drag and friction (i.e., losses) the vehicle experiences.

Yes, aeroplanes and ground vehicles differ significantly in this.

An easy to understand vehicle that can extract energy from air when their relative speeds are the same, is a cart with a vertical axis airfoil wind turbine.  The airfoils do not "catch" wind, they act like aeroplane wings, generating torque from the pressure differential on different sides of the blade.  During any motion of the vehicle, the VAAWT is rotating.  When the vehicle travels downwind at the same speed as the wind, the blades of the VAAWT can still extract energy from the wind in all phases except when the blade is in its extremum position with respect to the travel direction.  It is obvious, since the blade is moving wirth respect to air surrounding it.  Because of the pressure differential principle, the direction of the wind is easily compensated by changing the blade orientation/attack angle.  The only limiting factor is how efficient you can make your vehicle, how small you can make the losses in its mechanisms.

A lot of words and no equations.
I demonstrated that I can predict exactly what happens using very few simple and well known equations.
While all I get from you is "It depends on the vehicle".

Facts:
- Yes a vehicle with no energy storage like a simple sail vehicle can drive only using available wind power thus up to wind speed in wind direction and no speed directly upwind.
- A vehicle that uses some form of energy storage can drive both upwind and for a limited amount of time proportional with amount of stored energy directly downwind.

Understanding the difference between power and energy may be critical in understanding the above two facts.

So all you need to now are this:

a) P = 0.5 * air density * area * coefficient of drag * (wind speed - vehicle speed)3  to get ideal so best case scenario for wind power available.
b) KE = 0.5 * mass * (vehicle speed)2
c) details about the vehicle energy storage if it has any.

Knowing the above 3 things you can predict exactly what happens and so understand how all this vehicle work.

Offline electrodacusTopic starter

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Re: Newton's third law problem.
« Reply #107 on: November 24, 2022, 06:02:47 pm »
Direct upwind is trivial to demonstrate: just put an efficient horizontal turbine on a cart, and use a very low gearing to the wheels (i.e. turbine turns many tens of times per one rotation of the wheels).  Make it a VAWT and the cart will move regardless of the wind direction.

This matches my Lego trike I demonstrated earlier, and whose exact behaviour I described mathematically (in terms of velocities or displacements, and gear ratio); instead of wind, it used a spool of thread, or a Lego chain/track.

If one were to build a model where the ground wheel is actually a pulley with a wire looped around it and fixed to ground at both ends, it shows that no slip is required at all for it to function as described.  Indeed, if the wire is looped many times around the pulley, and fixed to the pulley at the midpoint, then no slip is even possible if one uses e.g. thin steel cable.

I will assume you have basic electricity knowledge.

Vehicle has a wind turbine connected to an electric generator.
The electric generator is connected to an electric motor that drives the wheels.
Based on wind speed and wind turbine swept area 1000W are available from the wind.
That means wind pushes against the vehicle with 1000W so if all 1000W output from the wind turbine are applied to an ideal 100% efficient electric motor the best that the vehicle can do is stay in the same place it is.

So the problem of you not understanding can come from
a) Not understanding that wind wants to accelerate the vehicle in the direction of the wind and so if your wind turbine output 1000W electrical of mechanical power you need 1001W at the wheels in order to begin to accelerate the vehicle mass against wind direction with 1W
b) Not understanding what power is and that if you include time you deal with energy
So you can wait for 2 seconds and store (in some energy storage device) 2000Ws worth of energy then you can use that stored energy to accelerate for say 1 second at 2000W or for 200ms at 10kW.
No energy storage means you can not accelerate the vehicle directly upwind. 

Offline electrodacusTopic starter

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Re: electrodacus' problem with Physics.
« Reply #108 on: November 24, 2022, 06:04:19 pm »

Online Nominal Animal

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Re: Newton's third law problem.
« Reply #109 on: November 24, 2022, 07:43:56 pm »
A lot of words and no equations.
Well, it is better than unphysical nonsense and equations unrelated to the physical phenomena at hand.  You seem to believe that if an equation applies in some specific situation, it must apply always, and that just isn't so.

Like I explained, if a vehicle uses the fixed ground instead of surrounding air in its propulsion mechanism, the amount of energy it can obtain from wind is not relative to the vehicle speed, it is relative to the ground.  So no subtracting vehicle speed from the wind speed relative to ground.
Extracting the energy is only an engineering problem.

Because of the Venturi effect, the exact wind speed just isn't an issue wrt. harvesting energy from it.

You insist on using static surfaces, ignoring all pressure-related effects, as if the vehicle is and has to be a simple rectangular box, with no internal mechanisms and only interacting with its environment via elastic collisions.  It is silly, and quite annoying.

You need to move past your preconceptions.  For example, you could start gently, and consider a vehicle with a very aerodynamic shape, say saucer-shape with a sharp edge, with upper and lower curvatures different (to balance out any vertical forces, including lift, due to the pressure differential), and with a Gorlov helical turbine poking up on top.  It has minimal drag, and the turbine efficiency is about 35%.  It typically operates at tip speed ratio over 1, which means that the induced flow rate due to rotation of the turbine is greater than the flow rate with respect to the axis.  Go read Gorlov's 2001 paper on it, but do recall that it only considers the properties of a stationary turbine.

And before you assert it, no, a moving turbine is not the same thing as stationary turbine in zero-wind situation.  It only matches if we assume the turbine is not moving in either case, and that's not going to happen with a moving turbine.  Because of the tip speed ratio being over 1, even when the wind speed approaches zero relative to the turbine axis, the turbine isn't going to stop (unless it has bad bearings or other significant losses).  Because it can keep accelerating the vehicle all the way, it will be less efficient at that particular point compared to speeds immediately above and below, but it isn't zero even there.

What makes that seemingly simple construction interesting, is the fact that airflow speed varies as a distance from static surfaces like the ground, below the boundary layer.  This means that along the vertical turbine axis, there is always a range of wind speeds relative to the axis, and because the wind direction does not affect the turbine, it can extract energy from the wind even when the vehicle is traveling downwind at the nominal wind speed.  This applies even to wind tunnels (and in those, it is most noticeable, because they have laminar flow patterns by design; in nature, wind tends to be a bit turbulent).  That sort of a vehicle does not even need wheels, it can even use a propeller for the propulsion, as long as it keeps close to a static surface (ground), and still achieve faster than nominal wind speed downwind or upwind.

When you wrap your mind around that, go look at aerodynamics, propulsion, and so on, and expand your understanding from there.  Reconsider the models and practical examples I've shown earlier in this thread. Don't get stuck in your preconceived notions just because you're emotionally heavily invested in them.  Learn to entertain ideas and theories and models that you do not believe are true, and learn how to rationally examine why your beliefs and the idea/theory/model do not agree.
« Last Edit: November 24, 2022, 07:47:13 pm by Nominal Animal »
 

Online PlainName

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Re: Newton's third law problem.
« Reply #110 on: November 24, 2022, 07:50:19 pm »
Quote
If by pushing you mean accelerating then you need to apply power to the propeller.

I stopped reading there since it's obvious you're already predetermined to go off on a distractions again. Recall:

"Forget where the power comes from for the moment and look at how it's actually working"

You even quoted that, yet the first second thing you say is "you need to apply power to the propeller".

And, to round it off, if you're pushing along at 5m/s or 10m/s or <any>m/s you are NOT accelerating. If it were accelerating I would say "it's accelerating".
 

Offline electrodacusTopic starter

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Re: Newton's third law problem.
« Reply #111 on: November 24, 2022, 08:41:14 pm »
Well, it is better than unphysical nonsense and equations unrelated to the physical phenomena at hand.  You seem to believe that if an equation applies in some specific situation, it must apply always, and that just isn't so.

Like I explained, if a vehicle uses the fixed ground instead of surrounding air in its propulsion mechanism, the amount of energy it can obtain from wind is not relative to the vehicle speed, it is relative to the ground.  So no subtracting vehicle speed from the wind speed relative to ground.
Extracting the energy is only an engineering problem.


There is no such thing as ground energy. There is only wind energy.
But more importantly we are only talking about Power

You can get as much energy from the wind as long as direct downwind vehicle is below wind speed.
You can do anything you want with that energy like:
Wasting it as heat (maybe apply brakes).
Increase vehicle kinetic energy and thus speed.
Storing it for later use
Or a combination of the above.


You insist on using static surfaces, ignoring all pressure-related effects, as if the vehicle is and has to be a simple rectangular box, with no internal mechanisms and only interacting with its environment via elastic collisions.  It is silly, and quite annoying.

Surfaces can be static or dynamic like a propeller they will act as a sail and vehicle can gain kinetic energy if air particle hit the static or moving part of the vehicle and will lose kinetic energy if say propeller hits a air particle that has the same speed as the vehicle or it moves in the opposite direction before being hit by the propeller blade.   

You need to move past your preconceptions.  For example, you could start gently, and consider a vehicle with a very aerodynamic shape, say saucer-shape with a sharp edge, with upper and lower curvatures different (to balance out any vertical forces, including lift, due to the pressure differential), and with a Gorlov helical turbine poking up on top.  It has minimal drag, and the turbine efficiency is about 35%.  It typically operates at tip speed ratio over 1, which means that the induced flow rate due to rotation of the turbine is greater than the flow rate with respect to the axis.  Go read Gorlov's 2001 paper on it, but do recall that it only considers the properties of a stationary turbine.

And before you assert it, no, a moving turbine is not the same thing as stationary turbine in zero-wind situation.  It only matches if we assume the turbine is not moving in either case, and that's not going to happen with a moving turbine.  Because of the tip speed ratio being over 1, even when the wind speed approaches zero relative to the turbine axis, the turbine isn't going to stop (unless it has bad bearings or other significant losses).  Because it can keep accelerating the vehicle all the way, it will be less efficient at that particular point compared to speeds immediately above and below, but it isn't zero even there.

What makes that seemingly simple construction interesting, is the fact that airflow speed varies as a distance from static surfaces like the ground, below the boundary layer.  This means that along the vertical turbine axis, there is always a range of wind speeds relative to the axis, and because the wind direction does not affect the turbine, it can extract energy from the wind even when the vehicle is traveling downwind at the nominal wind speed.  This applies even to wind tunnels (and in those, it is most noticeable, because they have laminar flow patterns by design; in nature, wind tends to be a bit turbulent).  That sort of a vehicle does not even need wheels, it can even use a propeller for the propulsion, as long as it keeps close to a static surface (ground), and still achieve faster than nominal wind speed downwind or upwind.

When you wrap your mind around that, go look at aerodynamics, propulsion, and so on, and expand your understanding from there.  Reconsider the models and practical examples I've shown earlier in this thread. Don't get stuck in your preconceived notions just because you're emotionally heavily invested in them.  Learn to entertain ideas and theories and models that you do not believe are true, and learn how to rationally examine why your beliefs and the idea/theory/model do not agree.


OK I will give you a concrete example with numbers that you can verify in a real world test.

35% efficient wind turbine installed on top of a vehicle. Wind turbine swept area say for simplicity 1m2


a) vehicle drives at +10m/s in a day with no wind so wind speed 0m/s
b) vehicle is stationary 0m/s and head wind speed is -10m/s
c) vehicle speed is +10m/s and head wind speed is -20m/s
d) vehicle speed is +10m/s and tail wind is +10m/s
e) vehicle speed is +10m/s and tail wind is +6m/s

For all this cases you use this equation to find what the wind turbine power output will be.

Pw = 0.5 * 1.2 * 1 * 0.35 * (wind speed - vehicle speed)3

If you can prove that this equation will not provide the correct result for any of the a) to e) cases or any other case you can think of then you can say you proved me wrong.

The mistake you make is to think there is not always an equal and opposite reaction to any action basically the title of this thread.

Offline electrodacusTopic starter

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Re: Newton's third law problem.
« Reply #112 on: November 24, 2022, 08:45:26 pm »

And, to round it off, if you're pushing along at 5m/s or 10m/s or <any>m/s you are NOT accelerating. If it were accelerating I would say "it's accelerating".

You can not get there (above wind speed directly downwind) unless you push the vehicle or stored energy pushes vehicle.

So from that point you mentioned 50% above wind speed without any stored energy your vehicle can only decelerate due to frictional losses and there is no way to accelerate as wind power available there is zero and there is no such thing as ground power.

Offline fourfathom

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Re: Newton's third law problem.
« Reply #113 on: November 24, 2022, 09:27:03 pm »
Nominal, what did I tell you???
We'll search out every place a sick, twisted, solitary misfit might run to! -- I'll start with Radio Shack.
 

Online Nominal Animal

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Re: Newton's third law problem.
« Reply #114 on: November 24, 2022, 09:33:29 pm »
Nominal, what did I tell you???
I'm an easily socially manipulated sucker, I know.  :-[

But the demand to "prove them wrong" just goes over the top.  As if the physical Lego model that behaves as I described and contrary to their description was not proof enough.

Time to use the Ignore list, I guess.
 

Offline james_s

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Re: Newton's third law problem.
« Reply #115 on: November 24, 2022, 09:42:10 pm »
 :palm:  :horse:
 

Offline electrodacusTopic starter

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Re: Newton's third law problem.
« Reply #116 on: November 24, 2022, 09:44:08 pm »
I'm an easily socially manipulated sucker, I know.  :-[

But the demand to "prove them wrong" just goes over the top.  As if the physical Lego model that behaves as I described and contrary to their description was not proof enough.

Time to use the Ignore list, I guess.

You do not have the explanation of how the Lego model works.
I do and the equations exactly predict what the Lego model shows in real world.

a) The input power to the Lego is the force and speed you apply to the string.
b) The output power can not be higher so vehicle could not move away from the direction the string is pulled without including energy storage.
 
So while you pull the string if you do that slow enough you will notice that you apply both a force and there is a speed for the string but the vehicle is not moving meaning the input energy was stored unless you can see that radiated as heat to the outside world (part of it will be radiated but a small percentage).
Then when enough energy was stored to allow the vehicle to move against the direction the sting moves it will do so but then it will need to again stop accelerating to charge and then accelerate again.
This pause to charge then accelerate cycles are fast enough that your brain will not be able to detect same as you can not detect that a video is made out of individual still frames so for a few ms the image is unchanged but your brain (and mine and anyone else's) will think that motion is continues.
« Last Edit: November 24, 2022, 09:46:14 pm by electrodacus »
 

Online PlainName

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Re: Newton's third law problem.
« Reply #117 on: November 24, 2022, 09:47:39 pm »

And, to round it off, if you're pushing along at 5m/s or 10m/s or <any>m/s you are NOT accelerating. If it were accelerating I would say "it's accelerating".

You can not get there (above wind speed directly downwind) unless you push the vehicle or stored energy pushes vehicle.

So from that point you mentioned 50% above wind speed without any stored energy your vehicle can only decelerate due to frictional losses and there is no way to accelerate as wind power available there is zero and there is no such thing as ground power.

"Forget where the power comes from for the moment and look at how it's actually working"

See, I told you it was utterly pointless and useless to try explaining to you. You simply cannot get your mind out of the groove it's worn, and you will drop in any distraction going in order to wear that groove deeper.
 

Offline electrodacusTopic starter

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Re: Newton's third law problem.
« Reply #118 on: November 24, 2022, 09:54:56 pm »
"Forget where the power comes from for the moment and look at how it's actually working"

See, I told you it was utterly pointless and useless to try explaining to you. You simply cannot get your mind out of the groove it's worn, and you will drop in any distraction going in order to wear that groove deeper.

So are you saying that is irrelevant to know the input power available for this wind only powered vehicle ?

Without knowing the answer to that question you will not be able to predict anything about the motion of that vehicle.
So either post the equation describing the wind power available to vehicle or you are just wasting my time and others that read this.

Online PlainName

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Re: Newton's third law problem.
« Reply #119 on: November 24, 2022, 10:01:37 pm »
Quote
So are you saying that is irrelevant to know the input power available for this wind only powered vehicle ?

At this point, yes. Later we will figure out what power we need and where it comes from, but right now we don't even know what use it would be! Well, obviously, we do but you don't.

Edit: rhetorical. I have no intention of spending another 2 months battling your mental illness or whatever it is that causes you to stick in your rut.
 

Offline electrodacusTopic starter

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Re: Newton's third law problem.
« Reply #120 on: November 24, 2022, 10:16:22 pm »
Quote
So are you saying that is irrelevant to know the input power available for this wind only powered vehicle ?

At this point, yes. Later we will figure out what power we need and where it comes from, but right now we don't even know what use it would be! Well, obviously, we do but you don't.

Edit: rhetorical. I have no intention of spending another 2 months battling your mental illness or whatever it is that causes you to stick in your rut.

The first thing you need to predict anything is the input wind power available to vehicle.
If there is no input wind power available then vehicle will not be able to move so there is nothing you can say or predict about.

After you know that you can look at design to figure if it has or not an energy storage device.
If it exceeds wind speed directly downwind or it drives at any speed directly upwind you know for sure energy storage is involved as else it can not work based on currently agreed laws of physics.
Then if you do the test correctly and look close enough at the data you will see that yes energy storage is involved in all of this cases.

I showed both the equations and the experimental data (for upwind variant) and both the equations and the experimental data fully agree.

Online IanB

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Re: Newton's third law problem.
« Reply #121 on: November 24, 2022, 10:42:53 pm »
The first thing you need to predict anything is the input wind power available to vehicle.
This is not true. We don't need to know how much power is available, it is not relevant. If the vehicle has any power available at all it is able to move in any chosen direction.

Quote
If there is no input wind power available then vehicle will not be able to move so there is nothing you can say or predict about.
Yes, of course. See above.

Quote
After you know that you can look at design to figure if it has or not an energy storage device.
There is no reason to do this, since it is not relevant.

Quote
If it exceeds wind speed directly downwind or it drives at any speed directly upwind you know for sure energy storage is involved as else it can not work based on currently agreed laws of physics.
This is not true.

Quote
Then if you do the test correctly and look close enough at the data you will see that yes energy storage is involved in all of this cases.
This is not true. If the mathematical models do not include energy storage, then there cannot be any energy storage.

Quote
I showed both the equations and the experimental data (for upwind variant) and both the equations and the experimental data fully agree.
You have never shown any such thing.
 

Offline electrodacusTopic starter

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Re: Newton's third law problem.
« Reply #122 on: November 24, 2022, 11:02:02 pm »
This is not true.
This is not true.
This is not true.

That is all that you said  "This is not true" .  No equation or proof for any of those not true claims.
This is a physics not a math question.
As mentioned with math you can also say a locked 1:1 gear ratio can drive upwind.

Online IanB

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Re: Newton's third law problem.
« Reply #123 on: November 24, 2022, 11:18:29 pm »
As mentioned with math you can also say a locked 1:1 gear ratio can drive upwind.

This is not true either. If you think it is true, demonstrate it.
 

Offline electrodacusTopic starter

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Re: Newton's third law problem.
« Reply #124 on: November 24, 2022, 11:43:29 pm »

This is not true either. If you think it is true, demonstrate it.

You did that yourself with your gif animation.

You had a 3:2 gear ratio
Showed a wheel traveling 3 squares and the other 2 squares while vehicle also moved one square.
I mentioned to fix one of the moving surfaces to represent the earth and your answer was

"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 asked if you observe such a thing in reality meaning treadmill moves one square relative to ground while vehicle moves two squares also relative to ground.

I obviously got no answer from you.
In the same way you can claim that with a 1:1 gear ratio the vehicle moves 2 squares while treadmill does not move at all.


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