Split Thread The validity of classical physics (split from: DWFTTW)

[humber]

A BRIEF INTERMISSION...

I think that you can answer the questions, John, without once saying "frame of reference". Heresy, again.

Speaking of simplifying things, I was just thinking how unecessarily complicated it was to say that in orbit the gravitational force is balanced by the centrifugal force, to explain the weightlessness felt. I said that that was problematic because there is not usually thought to be such a beast as centrifugal force.

Yes, another notional force.

There is the simpler description, which is that there is only the gravitational force, which is the centripetal force required to cause the acceleration, changing the velocity by changing the vector. When you take a turn in a car, similarly, in the horizontal direction, there is just the centripetal force applied via the seatbelt, door, etc. making your body follow that curve, and via the road on the wheels to turn the car.

When you turn the steering wheel, that changes the position of the contact patch of the tyre. The car reacts against that frictional force, so changing direction. You will feel those forces upon you via the seat, perhaps.
If as a result, you are accelerated forward, then your velocity will change and you will gain some KE until restrained by the belt. Your KE will be dissipated through various means, within your body for example, while the seat belt will be stretched according to the applied force, so retraining any further motion.

Forces come in pairs though, so doesn't this description break Newton's Third? Oh no, of course, there is a gravitational force on the planet, equal to the force on the orbiting body. So, is there a centrifugal force, too, of a person against their seatbelt? Isn't that what you feel at the end of the string when you whirl something round? The mass may 'experience' an inward force, but you definitely feel an outward pull.

There is the force of gravity that is met by an equal force from the ground.
That does not make the force upon you zero, but your velocity zero.
The force is real, it is the reaction due to the 'elasticity' of the supporting mass. While in free-fall in a vacuum, that opposing force is missing. Newton works from there, so you gain velocity and KE.

As Clive said, centrifugal force on the siring is an illusion. You pull on the string to make the object change its course from a straight line; a tangent to the string. That requires acceleration, and so the force from you. It feels like it is pulling, but that is just a sensory illusion. If you close your eyes and concentrate, you can correct for that.

Is that better, according to Newton? There are always pairs of forces, but the body to which they apply are different, so each can feel a net unbalanced force. In the usual situation where your weight is resisted by the normal force, it's easy to think of those as the pair of forces that Newton's Third refers to, but are there actually four forces - your weight, the "weight" of the earth (it's gravitational response up towards you), the normal force, i.e. the physical resistance of the earth's surface, and your physical resistance to that, its pair?

...OK. Ding ding, round 83

There are two 'static' forces. Gravity and the normal reactive force of the ground. One is a reaction to the other.

 

[mender]

The amount of energy needed for the cart to travel at windspeed has already been measured, nothing arbitrary about it. The method of getting that energy from the wind while at wind speed is pretty standard physics.

Humber, you have some of the basics needed to understand how the cart works but you'll never get any farther than you are if you continue with your present debating style. Spend less time trying to push buttons and more time trying to learn.

Ask and ye shall receive. Be an ignoramus and get ignored.

 

[spork]

That strikes #8 off the list.

I think you're way too quick to strike items from the list. Even a broken clock is right twice a day. Just as you require people to second items to put them on the list, you should require humber to demonstrate he can at a bare minimum repeat the comment that causes you to think he understands something.

Under those circumstances I doubt very much you'll ever get to cross an item off the list.

 

[mender]

That means power is proportional to V^3.
That cannot apply to balloons or parachutes, because they would then be able to produce more power than the wind.

Exactly, spork. Like here where he repeats the statement then demonstrates that he doesn't understand it.

 

[humber]

The amount of energy needed for the cart to travel at windspeed has already been measured, nothing arbitrary about it. The method of getting that energy from the wind while at wind speed is pretty standard physics.

The measurements have not been correctly taken, nor the motor power monitored. Nor has the cart been demonstrated to develop any of the force or power indicated by Drela's paper. It cannot actually climb up the belt, unless already at "windspeed".
The treadmill is in no way connected to a cart in real wind

Humber, you have some of the basics needed to understand how the cart works but you'll never get any farther than you are if you continue with your present debating style. Spend less time trying to push buttons and more time trying to learn.

I do not agree that you are correct. There are numerous inconsistencies, and what "claims" there are, can be explained by other means.

Ask and ye shall receive. Be an ignoramus and get ignored.

I am not inclined to religious belief, Mender.

 

[Christoph]

Interesting discussion! There are two things I find curious:
1) Directly downwind, faster than the wind, powered by the wind, seems to me to be impossible for many reasons. Yet, the one person on this forum who opposes the idea finds himself the object of attack and ridicule! I would have expected things to be the other way around. I would have expected that the ones making this claim, which is unsubstantiated by either experiment or theory, to be under attack.
2) I see talk of comparing reference frames on the earth and on the moon. However, I see no relevance between that and the discussion at hand. It seems to me the talk should be about comparing reference frames between a treadmill and the earth. The treadmill is clearly a non-inertial rotating frame and the earth is (very nearly) an inertial frame. I think that is extremely important to take into consideration! How can anyone say there is relativity between the non-inertial frame of the treadmill and the inertial frame of the earth?

 

[Dan O.]

I wouldn't strike #8 off until he states that he has changed his mind and is able to demonstrate that.

Aw, I so wanted to scratch one off

I should have looked closer, the formula was right but there was no discussion of what that particular formula was applying to. Number 8 stands with a reference to our folly.

• "The force is approximately linearly proportional to the relative velocity of chute and wind." #2951 #3259 #3263

 

[humber]

I think you're way too quick to strike items from the list. Even a broken clock is right twice a day.

A clock with no hands.

Just as you require people to second items to put them on the list, you should require humber to demonstrate he can at a bare minimum repeat the comment that causes you to think he understands something.

humber. Accept no substitutes.

Under those circumstances I doubt very much you'll ever get to cross an item off the list.

I imagine that is true.

 

[humber]

Aw, I so wanted to scratch one off

I should have looked closer, the formula was right but there was no discussion of what that particular formula was applying to. Number 8 stands with a reference to our folly.

• "The force is approximately linearly proportional to the relative velocity of chute and wind." #2951 #3259 #3263

Too bad. Neutered.

 

[RossFW]

Interesting discussion! There are two things I find curious:
1) Directly downwind, faster than the wind, powered by the wind, seems to me to be impossible for many reasons. Yet, the one person on this forum who opposes the idea finds himself the object of attack and ridicule! I would have expected things to be the other way around. I would have expected that the ones making this claim, which is unsubstantiated by either experiment or theory, to be under attack.
2) I see talk of comparing reference frames on the earth and on the moon. However, I see no relevance between that and the discussion at hand. It seems to me the talk should be about comparing reference frames between a treadmill and the earth. The treadmill is clearly a non-inertial rotating frame and the earth is (very nearly) an inertial frame. I think that is extremely important to take into consideration! How can anyone say there is relativity between the non-inertial frame of the treadmill and the inertial frame of the earth?

Humbers twin Brother!!

Christoph,

If you care to look, you will find this thread in and offshoot of "Down-wind faster than the wind" wjich includes several videos, diagrams and detailed explanations of how it is possible to make a cart do just that, and has been going on for months with thousands of posts.

The surface of the treadmill is NOT rotating, it is linear motion.An inertial frame of reference exists traveling in the same direction and at the same speed as the top surface of the belt. A cart on the treadmill is in an equivelent state of motion to a cart traveling downwind at the speed of the wind. If the cart is then able to travel faster than the belt, it is demonstrating an ability to go faster than wind-speed.
One person, by the name of Humber, has refused to accept this. In subsequent discusstions we have found out he also believes-

-Hot air balloons do not move at the speed of the wind and can be propelled laterally using their burner alone.

-Boats travelling at the speed of the water around them leave bow waves.

-Kites can fly without a string.

-Something can have "No kinetic energy in any frame."

-Something can have no movement in a particular direction in any frame.

And the list goes on....

Still want to defend this guys physics?

Do a little reasearch before butting in....

 

[humber]

Humbers twin Brother!!

Christoph,

If you care to look, you will find this thread in and offshoot of "Down-wind faster than the wind" wjich includes several videos, diagrams and detailed explanations of how it is possible to make a cart do just that, and has been going on for months with thousands of posts.

The surface of the treadmill is NOT rotating, it is linear motion.An inertial frame of reference exists traveling in the same direction and at the same speed as the top surface of the belt. A cart on the treadmill is in an equivelent state of motion to a cart traveling downwind at the speed of the wind. If the cart is then able to travel faster than the belt, it is demonstrating an ability to go faster than wind-speed.
One person, by the name of Humber, has refused to accept this. In subsequent discusstions we have found out he also believes-

-Hot air balloons do not move at the speed of the wind and can be propelled laterally using their burner alone.

-Boats travelling at the speed of the water around them leave bow waves.

-Kites can fly without a string.

-Something can have "No kinetic energy in any frame."

-Something can have no movement in a particular direction in any frame.

And the list goes on....

Still want to defend this guys physics?

Do a little reasearch before butting in....

Most of those, within context and missing components restored, are correct and the remainder, sheer misrepresentation.
This is from a pilot who equates slower with backwards and free-fall to the Earth with zero G. No need to run out of fuel, then, Captain.

 

[mender]

It cannot actually climb up the belt, unless already at "windspeed".

Almost right. It cannot climb up the belt unless it goes faster than windspeed. Since it does climb up the belt even when the treadmill is inclined as clearly seen in the videos and proven here in my home, the cart goes faster than windspeed.

Thank goodness. I was beginning to think you'd never get it, humber.

Now we have to work on humberest (the new guy).

 

[Christoph]

Humbers twin Brother!!

Christoph,

If you care to look, you will find this thread in and offshoot of "Down-wind faster than the wind" wjich includes several videos, diagrams and detailed explanations of how it is possible to make a cart do just that, and has been going on for months with thousands of posts.

The surface of the treadmill is NOT rotating, it is linear motion.An inertial frame of reference exists traveling in the same direction and at the same speed as the top surface of the belt. A cart on the treadmill is in an equivelent state of motion to a cart traveling downwind at the speed of the wind. If the cart is then able to travel faster than the belt, it is demonstrating an ability to go faster than wind-speed.

Still want to defend this guys physics?

Do a little reasearch before butting in....

I see. So, according to you, posting an opinion on a topic is “butting in”? What is this forum good for then? Only people who share the same opinion should be posting here?
I am not defending Humber’s physics in general, as I have no idea about his qualifications. I simply find it curious that the one person who is skeptical of the DDW claim is under such attack. I do not agree that the claim is proven by any means. Certainly, there is no evidence of a cart actually moving directly downwind, faster than the wind, whilst being powered by the wind, and I have done some research on this. To say the “surface of the treadmill is in linear motion” is false. Pick a point on any rotating wheel and you can call it a surface but it is not in linear motion. Just because the treadmill surface has been created flat for convenience, does not change the fact that it is part of a rotating belt. It is clearly a rotating frame and in no way relatively equivalent to the inertial frame of the earth. Whatever is happening on the treadmill may very well be faster than the treadmill, but it may also be attributed only to the fact that the surface is rotating at the same time the wheels are rotating. If that is the case, then there is no reason to believe that what happens on the treadmill can, or will, happen on the road.

 

[Dan O.]

Interesting discussion! There are two things I find curious:

High Chris, welcome to our little thread where we ridicule arguments that contradict what's been known about classical physics for over 300 years.

1) Directly downwind, faster than the wind, powered by the wind, seems to me to be impossible for many reasons. Yet, the one person on this forum who opposes the idea finds himself the object of attack and ridicule! I would have expected things to be the other way around. I would have expected that the ones making this claim, which is unsubstantiated by either experiment or theory, to be under attack.

If you want to discuss the curious little cart, we have a whole other thread for that which isn't distracted by misunderstandings of the laws of classical physics. You are welcome to present your reasoning for why the cart can't work over there as long as you are using real physics to support your claim. But keep in mind, almost everyone participating here has either built one of these carts or solved the math that proves that the cart works.

2) I see talk of comparing reference frames on the earth and on the moon. However, I see no relevance between that and the discussion at hand.

The parameters for this thread were listed in the initial post that created the split. There has been little talk of the treadmill or cart here.

It seems to me the talk should be about comparing reference frames between a treadmill and the earth. The treadmill is clearly a non-inertial rotating frame and the earth is (very nearly) an inertial frame. I think that is extremely important to take into consideration! How can anyone say there is relativity between the non-inertial frame of the treadmill and the inertial frame of the earth?

The rotating parts of the treadmill are usually covered to prevent liability issues. They are of little importance to us since our primary interest in a treadmill is the mostly flat surface on top with a constant linear velocity that creates a suitable platform for studying a little cart traveling at or near a fixed speed equal to the speed of the wind.

 

[sol invictus]

It is clearly a rotating frame and in no way relatively equivalent to the inertial frame of the earth.

I don't follow you. The frame we're interested in is one that moves at the same constant speed and in the same constant direction as the top surface of the treadmill belt. That's an inertial frame, by definition. Of course the remainder of the treadmill belt is not at rest in that frame, but that isn't relevant for the cart.

If you had some other frame in mind, please enlighten us as to what it is.

 

[spork]

The treadmill is in no way connected to a cart in real wind

I got nothing. I just really enjoy the pure wrongness of this.

Directly downwind, faster than the wind, powered by the wind, seems to me to be impossible for many reasons.

Yes, it's supposed to SEEM wrong. That's what makes it such a good brainteaser.

Yet, the one person on this forum who opposes the idea finds himself the object of attack and ridicule!

His "ideas" are under attack because they are absolutely ludicrous.

I would have expected that the ones making this claim, which is unsubstantiated by either experiment or theory, to be under attack.

I might expect that as well. However, our cart has been fully substantiated by experiment and theory.

The treadmill is clearly a non-inertial rotating frame and the earth is (very nearly) an inertial frame.

The cart only ever touches the flat upper surface of the belt. This surface which moves at a constant velocity can be used to define an inertial frame. If the cart followed the belt all the way around like George Jetson I'd be inclined to agree there's a problem with our inertial frame. Do you honestly think the cart sees the top surface of this belt any differently than it would any other flat level surface moving at constant velocity? How do it know the surface is dissappearing behind it only to reappear in front?

How can anyone say there is relativity between the non-inertial frame of the treadmill and the inertial frame of the earth?

No one does.

I am not defending Humber’s physics in general, as I have no idea about his qualifications.

What do his "qualifications" have to do with anything. If he were to have a PhD in physics would that make the nonsense he spews more correct!?

I do not agree that the claim is proven by any means.

Perhaps you don't understand what "proof" means. There are a great many things considered proved even though you personally might not be able to follow the proofs. Is it only proved once we produce a proof simple enough for you to follow, or is is sufficient once proved to a great many people skilled in the art?

Certainly, there is no evidence of a cart actually moving directly downwind, faster than the wind, whilst being powered by the wind

Absolute statements rarely work out as you wish - more so when they're entirely wrong.

...and I have done some research on this.

And I have built, tested, and analyzed these carts. Your research is lacking.

Just because the treadmill surface has been created flat for convenience, does not change the fact that it is part of a rotating belt.

Now you're just messing with us - right? humberer?

 

[fredriks]

I am not defending Humber’s physics in general, as I have no idea about his qualifications. I simply find it curious that the one person who is skeptical of the DDW claim is under such attack.

Have you read a single one of humbers posts? I can't understand that someone that understands some physics don't see through humber after at most a couple of posts.

Do you know it is more than 3000 posts in the thread, probably over 1000 by humber. It is a possibility that people have learned something about humber while reading those posts.

 

[humber]

Almost right. It cannot climb up the belt unless it goes faster than windspeed. Since it does climb up the belt even when the treadmill is inclined as clearly seen in the videos and proven here in my home, the cart goes faster than windspeed.

Thank goodness. I was beginning to think you'd never get it, humber.

Now we have to work on humberest (the new guy).

That means that it moves just a little faster than zero. It does not climb the incline in a way that means anything more than gravity adding a bias to the cart's balance mechanism, in the same way that a small mass will tilt a set of scales one way or the other.
The videos also demonstrate that there is very little power produced, and the cart can be dynamically controlled with the slightest puch of a fork.

 

[humber]

I don't follow you. The frame we're interested in is one that moves at the same constant speed and in the same constant direction as the top surface of the treadmill belt. That's an inertial frame, by definition. Of course the remainder of the treadmill belt is not at rest in that frame, but that isn't relevant for the cart.

If you had some other frame in mind, please enlighten us as to what it is.

I can explain that because I have made a similar point much earlier. The belt is simply a moving surface with harmonic motion. As far as the cart is concerned, it is a single point of physical contact with treadmill motor, that could easily be a roller, as a belt. It does no imply motion for the cart.

 

[humber]

I got nothing. I just really enjoy the pure wrongness of this.

Right first time!

Yes, it's supposed to SEEM wrong. That's what makes it such a good brainteaser.

It's a no-brainer.

His "ideas" are under attack because they are absolutely ludicrous.

Not as ludicrous as forcing all observers to be at windspeed, while they watch a cart stay still on a belt. Park the jumbo, and fly the airport. Same thing.

I might expect that as well. However, our cart has been fully substantiated by experiment and theory.

Where all those words have their own frame of reference, or simply framed.

The cart only ever touches the flat upper surface of the belt. This surface which moves at a constant velocity can be used to define an inertial frame.

If the belt is a constant velocity, and increased velocity is moving up the belt, how is displacement represented?

If the cart followed the belt all the way around like George Jetson I'd be inclined to agree there's a problem with our inertial frame.

George Jetson is a cartoon character. An easy mistake to make.

Do you honestly think the cart sees the top surface of this belt any differently than it would any other flat level surface moving at constant velocity? How do it know the surface is dissappearing behind it only to reappear in front?

No more than it "thinks" its traveling.

No one does.

What do his "qualifications" have to do with anything. If he were to have a PhD in physics would that make the nonsense he spews more correct!?

That's why I don't tell you.

Perhaps you don't understand what "proof" means. There are a great many things considered proved even though you personally might not be able to follow the proofs. Is it only proved once we produce a proof simple enough for you to follow, or is is sufficient once proved to a great many people skilled in the art?

For more of the same:
http://en.wikiquote.org/wiki/Donald_Rumsfeld

Absolute statements rarely work out as you wish - more so when they're entirely wrong.
And I have built, tested, and analyzed these carts. Your research is lacking
Now you're just messing with us - right? humberer?

One more time now...