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

[humber]

You want me to refute your moral judgment of the cart's motion?

A quick tour of the dictionary will reveal your error, but if you like, both cases.
I would add that four-vectors may look silly if you don't.

No.

Why not?

 

[sol invictus]

A quick tour of the dictionary will reveal your error, but if you like, both cases.
I would add that four-vectors may look silly if you don't.

No idea what you're blabbering about.

Why not?

Because the question made no sense.

 

[humber]

Gosh, I'm intruiged as to what Spacediver's answer might have been. Mine will be forthcoming if you can phrase the question in a scientific manner, or just a manner that is a lot less meaningless, assuming I'm still around by then.

That is the question John, You do hold to the view that the observer is the important matter, and not the external environment? That is the point of the box car, I expect?

Those are questions about that observer's knowledge. How else can I phrase them?

I offer you the alternative to please explain the consequences of zero relative velocity at waterspeed; that which I cheekily refer to as "bullet time" or "ducks in a row". I find that this to be an inevitable consequence. Do you?

 

[spacediver]

I put this to Spacediver.
-----
You are driving in your car, and you put your hand out of the window and feel the air. The speedometer says 50kph. You now arrange a fan or some other device to slow the wind passing over your window. If you now put your hand out and "feel" 10kph, do you ignore your speedometer and the car ahead as evidence to the contrary?
If you now shut out that information, do you believe the wind? Perhaps if you knew of the fan, no, but if it were to be done without you "knowing" it, would you then believe it, and of what use would that be?

the reason i didn't answer this was because I have no clue what the question is. Please rephrase the question in a manner appropriate for a physics exam.

 

[humber]

No idea what you're blabbering about.

OK, then I will be more specific, as you so often ask that I should be !

I would like you to please explain how it seems that the cart is not going in the expected direction of along with the belt, but against the belt.

It seems to me that the the translation by the beltspeed vector should see the cart go along with the belt. I have mentioned this before, but it remains unresolved.

If the cart moves with the belt, then as it's velocity increases, it gains KE, and consumes power; in fact exactly like the frame it is said to represent. All measurements are the same from any reference I choose.

I also noted that the current cart has a lot of seemingly odd 'backwards' things about it, like the KE and power problem, yet they are not consistent within each frame, or at least it seems quite difficult to confirm that.

However, it would seem that all of these effects are a result of going against the belt. Turning it around does the trick, but now I have no tailwind to drive the cart. I suspect that this is due to the lack of any real wind.

The belt laminar flow seems to be there, but I wonder how? There is certainly no wind except of course for that generated when traveling with the belt, but this is a common experience when simply walking in room, so I can't see a new "frame" as being a necessary condition.

This contradiction cannot be right, because surely equivalence says that it must work equally well in both directions, certainly as far as relative velocities go.
The oddest thing is that the belt-laminar flow seems to be the same in each case; with the belt. I think this is because the laminar flow is certainly attached to the belt, and would seem to indicate that going with the belt is the correct interpretation of that beltspeed translation, rather than that currently adopted.

The problem of the orange bothers me. When I move it either with the belt, or against the belt, it seems to gain KE w.r.t. the belt and ground by equal amounts. This too seems to be inconsistent with the operation of the current treadmill.

 

[humber]

the reason i didn't answer this was because I have no clue what the question is. Please rephrase the question in a manner appropriate for a physics exam.

OK, spacediver I did not know that.

The question is clear enough, I think. It's not about physics, but what the observer can besaid to know. A lot of emphasis is put on what the observer senses, like putting a hands in the breeze and seeing the road this way and that, but I don't seem to be able to connect this to the hobo, who senses nothing except for the internal environment.
So I wonder how this information, or lack of can be any use.

Now, of course I am being ironic in the above, but believe me, I do not understand how you can see this as relevant. I do understand the principle of the hobo idea, it's not that hard, is it? So why?
How can you simply ignore the consequences of the bullet time matter?
It is a consequence, I think.

This are a genuine questions. If you don't want to answer them, then I accept that, so there is no need to respond otherwise.

 

[humber]

I have claimed that the cart is just sitting on the belt, spinning its propeller.
A few weeks ago, I found in a book of Russian physics problems, a very similar example. If the first issue date is correct, this problem is at least 27 years old!

Note that is supports my contention that the cart is dependent upon friction, and that it is unstable! ("system Q!"). It also is uses "hovering".

 

[spacediver]

OK, spacediver I did not know that.

apologies. I should have said something instead of ignoring it.

The question is clear enough, I think. It's not about physics, but what the observer can besaid to know. A lot of emphasis is put on what the observer senses, like putting a hands in the breeze and seeing the road this way and that, but I don't seem to be able to connect this to the hobo, who senses nothing except for the internal environment.
So I wonder how this information, or lack of can be any use.

I still have no idea what you're asking. Go over some of the questions I've asked you. You'll see I've outlined the conditions clearly and phrased my questions concisely. Please do the same so I can give your question due diligence.

Now, of course I am being ironic in the above, but believe me, I do not understand how you can see this as relevant. I do understand the principle of the hobo idea, it's not that hard, is it? So why?
How can you simply ignore the consequences of the bullet time matter?
It is a consequence, I think.

I have no idea what bullet time matter means. Please just ask me the question normally, using established physics terminology.

Also, please do not bring treadmills into this as I'm not interested in treadmills.

I am, however, interested in your claim that a balloon tossed up in a moving and enclosed airplane will experience dissipation - something which nobody here except you believes. I'm assuming your fan and car question has something to do with this, but until you phrase it clearly I cannot answer.

 

[Clive]

I have claimed that the cart is just sitting on the belt, spinning its propeller.

I doubt it. Observe. Think!

A few weeks ago, I found in a book of Russian physics problems, a very similar example. If the first issue date is correct, this problem is at least 27 years old!

Note that is supports my contention that the cart is dependent upon friction, and that it is unstable! ("system Q!"). It also is uses "hovering".

This is ringing a bell for me. Don't tell me the author is one "Ivana B. Trolski"?

By the way, it also seems that you've tried to include an image of some kind in that post humber, maybe a page from the mystery Russian textbook? In any case the link (http://www.internationalskeptics.com/forums/attachment.php?attachmentid=12679&stc=1&d=1231817583) is also invalid!

 

[Brian-M]

WINDSPEED is not a defined word. If you insist on using words that have no standard definition, you must supply a definition.

Here's a few definitions to choose from.

(′win ′spēd)
(meteorology) The rate of motion of air.

WEATHER&METEOROLOGY


The rate at which air is moving horizontally past a given point: It may be a 2-minute average speed (reported as wind speed) or an instantaneous speed (reported as a peak wind speed, or gust):

Wind speed is the speed of wind, the movement of air or other gases in an atmosphere. It is a scalar quantity, the magnitude of the vector of motion.

Wind speed has always meant the movement of air in an outside environment, but the speed of air movement inside is important in many areas, including weather forecasting, aircraft and maritime operations, building and civil engineering. High wind speeds can cause unpleasant side effects, and strong winds often have special names, including gales, hurricanes, and typhoons. See the Beaufort scale.

 

[humber]

It was about the relationship between the hobo idea, and its relation to the treadmill, but I am not interested in the hobo itself, so I imagine we are at cross-purposes, spacediver.

I am, however, interested in your claim that a balloon tossed up in a moving and enclosed airplane will experience dissipation - something which nobody here except you believes. I'm assuming your fan and car question has something to do with this, but until you phrase it clearly I cannot answer.

Well, like you I am not sure what you are asking, but a balloon traveling in the air as it is tossed up, will dissipate energy against friction. This cannot be avoided, as the motion of the molecules is considered to be random and indelibly so.

As for jumping up and down in a van with air, where there is gravity, landing in the same spot, the solutions are numerous. I only need redirect some of the kinetic energy gained from the jump to generate a thrust.
An aerofoil section would do. More friction one side than the other.

Unless the hobo is to freeze, then the air may be at 300degrees Kelvin, so there is energy there too, meaning the hobo's position could be changed even if there were no gravity. The interesting thing is that the hobo can simply assert what his velocity is, and you cannot deny it, if for no other reason than you can't communicate that .That won't bother him, because it makes no difference too him?

I was taken to task for not considering the Moon, so I will. I'll use it to calculate my velocity. Perhaps my earlier point was; If you remove everything, what have you got?

 

[sol invictus]

I would like you to please explain how it seems that the cart is not going in the expected direction of along with the belt, but against the belt.

That's what the last 3,000 posts are about. It goes against the belt because it's designed to go DDWFFTW, and it works.

It seems to me that the the translation by the beltspeed vector should see the cart go along with the belt.

That sentence doesn't make sense. Perhaps you mean that if it weren't for the prop, it would eventually move along with the belt? That's true.

If the cart moves with the belt, then as it's velocity increases, it gains KE, and consumes power;

I don't know what "consumes power" means. Do you mean losses due to friction?

in fact exactly like the frame it is said to represent.

No - outside in the wind the cart moves DWFFTW, which means moving up-belt (as it does), not with the belt.

However, it would seem that all of these effects are a result of going against the belt. Turning it around does the trick, but now I have no tailwind to drive the cart. I suspect that this is due to the lack of any real wind.

Turning what around - the cart? That will make it less efficient.

The belt laminar flow seems to be there, but I wonder how? There is certainly no wind except of course for that generated when traveling with the belt, but this is a common experience when simply walking in room, so I can't see a new "frame" as being a necessary condition.

There's nothing "necessary" about frames. The fact is that the laws of physics are identical in all inertial frames. That means that the cart on the belt identically to a cart outside in a "real" wind, modulo a few insignificant finite size effects. Therefore if the cart moves upbelt, the cart outside will move DDWFFTW. It's that simple.

This contradiction cannot be right, because surely equivalence says that it must work equally well in both directions, certainly as far as relative velocities go.

No idea what "contradiction" you're talking about.

The problem of the orange bothers me. When I move it either with the belt, or against the belt, it seems to gain KE w.r.t. the belt and ground by equal amounts. This too seems to be inconsistent with the operation of the current treadmill.

Again, incomprehensible. An orange rolling on a belt will gradually start to move downbelt. It will not accelerate upbelt - for that you need something like the propeller.

 

[spacediver]

Well, like you I am not sure what you are asking, but a balloon traveling in the air as it is tossed up, will dissipate energy against friction. This cannot be avoided, as the motion of the molecules is considered to be random and indelibly so.

Do you agree with the following:

A plane is moving at a constant velocity. A person inside the plane tosses up a beachball towards the ceiling. The beachball will land directly where it started from, give or take a small margin due to random fluctuations of air molecules, but the beachball will not experience any air resistance in the direction opposite to the movement of the plane.

 

[Brian-M]

That's F'ING brilliant logic even for humber!!! Yo' humber, please show me how I cannot teletransport.

I second that motion!

Humber, while you're at it, please show me how I cannot levitate.

ETA:

Do it now.

BTW: I am doing it now. It's fun to levitate while typing.

 

[humber]

Do you agree with the following:

A plane is moving at a constant velocity. A person inside the plane tosses up a beachball towards the ceiling. The beachball will land directly where it started from, give or take a small margin due to random fluctuations of air molecules, but the beachball will not experience any air resistance in the direction opposite to the movement of the plane.

I any remotely realistic situation, the ballons position would be limited, but indeterminate.

 

[humber]

That's what the last 3,000 posts are about. It goes against the belt <snip>

You flatter yourself when you think this had anything to do with you.

 

[humber]

BTW: I am doing it now. It's fun to levitate while typing.

You fail to recognize the failure of your argument. No, you are not levitating.

 

[Brian-M]

You may argue, as you have, that the ground does not matter, but when the policeman with his doppler radar gives you a ticket, the clerk-magistrate is not going to care about your assertions of "equivalence"... [SNIP]

I actually read all the way to the last sentence before I realized it wasn't Humber.

Good work, Humb!

 

[sol invictus]

You flatter yourself when you think this had anything to do with you.

What had to do with me? And why would it be flattering? You're not making sense, as usual.

 

[spacediver]

I any remotely realistic situation, the ballons position would be limited, but indeterminate.

that's not an answer. I've provided a situation, and I'm asking you if the beachball's motion in the air is at all affected by the movement of the plane, even though it's going at a constant velocity. Importantly, the beachball is thrown AFTER the plane has accelerated to the constant velocity.