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

[humber]

Actually, the more I think about it, Humber is arguing that it is impossible to take 120 volts and convert it into 240 volts.

No, you just made that up.

The difference in velocity between wind and ground translates somewhat metaphorically to the difference in voltages between the positive terminal and electrical ground. It is the difference that lets you extract power.

No, electrons flow from -ve to +ve. You also need a current path of appropriate impedance.

Because the wind is moving at 10 mph over ground, humber argues that the cart cannot go faster than 10 mph over the ground. But in the electrical equivalent version, that means that if the source of your power is 10 volts, humber would be arguing that the output can never exceed 10 volts.

Seems he may be right. How do you get AC wind? How do you pass DC through a transformer?

But more importantly, arguing about the cart in electrical metaphors is only going to be one hell of a source of confusion to try and find the corresponding units for mechanical equivalents. We can talk about the cart in purely mechanical terms and understand how it works. We don't need to invent some electircal equivalent version of physical reality just so Humber can argue that his invocation fo the "maximum power theorem" had some relavence to teh conversation.

No, it's very good. Clear and direct notation. Works well with Matlab and notepad alike.

Switching to electrical metaphors is more a smokescreen for humber to hide that he doesn't understand it mechanically. The best way to understand the cart is to look at it for what it is, mechanically, rather than metaphorically.

The only smoke I see is being blown up someone's rear.
I can do the mechanical version too. Perhaps, first generate the equations of motion using calculus, and then do a Laplace to algebra.
I was thinking of a meta-mecha-techno hybrid. Any thoughts?

 

[jjcote]

The profile is 'A' no matter what the observer is doing. The boundary layer is viscously attached to the belt. Difficult for the observer to change that.

Does the observed belt speed change depending on what the observer is doing? In other words, doesn't an observer on the floor see it moving at 10 m/s, but an observer moving with the belt sees it as stationary (0 m/s)?

 

[humber]

And yet, somehow, every piece of electronic equipment in your house that uses a 5 volt power plane somehow connects into your wall outlet that has a 120 volt source.

Yes, it may do. The still transformer gets warm. The transformers are often part of a SMPS, though.

If I pull on a block and tackle with 10 pounds of force, I can lift 20 pounds of weight. Or I could pull on the rope at 15 meters per second and lift a weight at 30 meters per second.

If you insist on the electrical metaphor, then either force is voltage and velocity is current or force is current and velocity is voltage.

Not really. I insist on not allowing BS.

Either way, you can put your electrical power through a transformer and take an input "velocity" of 10 and have an output velocity of 20.

No power gain, but some loss, Dude.

Just like a block and tackle. Just like a lever.
Push the short end of a lever down an inch, adn the long end could move 2 inches. Push it down at 1 meter per second and teh long end could move at 2 m/s.

See-saws may go at the speed of sound because of this remarkable phenomenon. Children are in peril

Maximum power theorem doesn't say anything about transforming the power you have into different voltages or speeds. conservation of energy doesn't say anything about transforming your power ro energy ito other forms, possibly using simple machines to change your velocity but maintain the same amount of power or energy.

No, it assumes that you won't use it as a straw man. Conservation of energy doesn't say a lot, just rules.
Maximum Repetition Theorem is your game.

Even IF we accept electrical metaphors to look at the cart, Maximum power theorem has nothing to do with how the cart actually works.

Neither do you.

 

[humber]

Does the observed belt speed change depending on what the observer is doing? In other words, doesn't an observer on the floor see it moving at 10 m/s, but an observer moving with the belt sees it as stationary (0 m/s)?

Don't see how. Both observers see the belt going at the same speed, so it would be odd that the viscously attached layer would not be seen doing the same thing.

 

[humber]

Humber, I see a lot of foolish people have been distracting us from finishing our conversation. Forgive them, for they know not what they do. I'm just having difficulty understanding correctly how the BL reverses on the treadmill. I'm sure you're right, and just want your help in clearing up my obvious mistakes. Could you tell me, in the scenario we were discussing, based on your drawings:

Is the land-based 8 m/s to the right above or below the 6 m/s? (above/below)

Does it go at 8 m/s right to left above the treadmill, w.r.t. the still air/room/earth? (Y/N...it goes at).

Thanks again again.
John

Is it not clear now, John? I mean after the subsequent posts and drawings?

 

[fredriks]

1694 posts and still no clue about observers/reference frames etc....

 

[humber]

1694 posts and still no clue about observers/reference frames etc....

From your post count Fredriks, I would say that is the 68th time you've said that.

 

[GregLondon]

No power gain, but some loss, Dude.

power loss is irrelevant to the cart going faster than the wind.

If the cart is 60% efficient and the max power it can get from the prop/wheel combination is 10 watts, it still has 6 watts to work with, and it can use those 6 watts to go faster than the wind.

Nothing prevents power from being lost but still transform the power that's left into something faster than the wind.

Conservation of energy doesn't say a lot, just rules.

Like a swinging pendulum changes velocity, but maintains total energy.

Conservation of power doesn't require conservation of velocity.

The entire basis of your argument that teh cart can't go faster than teh wind appears to be based off of nothing more than you confusing power for velocity.

Power out cannot exceed power in. But velocity out CAN exceed velocity in, if you're willing to trade off the force available.

Maximum Repetition Theorem is your game.

You brought up an irrelevant theorem and can't acknowledge it. Not me.

 

[fredriks]

I have actually written a couple of serious constructive posts also but it has been clear from the start that serious constructive posts is completely useless in a "conversation" with you.

1694 posts and you are either so dense that you don't understand relative motion and other concepts in physics or are you are just playing.

By the way, I am still waiting for the answer for all my question I have asked you. Some questions.

What is a reference frame?

How can a treadmill be false?

 

[GregLondon]

(duplicate post deleted)

 

[humber]

power loss is irrelevant to the cart going faster than the wind.
If the cart is 60% efficient and the max power it can get from the prop/wheel combination is 10 watts, it still has 6 watts to work with, and it can use those 6 watts to go faster than the wind.

Then the cart will not get to windspeed because that requires a conservation-busting transfer of 100%

Nothing prevents power from being lost but still transform the power that's left into something faster than the wind.

I am afraid that Nature is a Mother.

Like a swinging pendulum changes velocity, but maintains total energy.

Or swinging a cat, or a dick

Conservation of power doesn't require conservation of velocity.

No, but that is a problem for 'relative' ideas based solely upon velocities.

The entire basis of your argument that teh cart can't go faster than teh wind appears to be based off of nothing more than you confusing power for velocity.

Good, eh?

Power out cannot exceed power in. But velocity out CAN exceed velocity in, if you're willing to trade off the force available.

True.

You brought up an irrelevant theorem and can't acknowledge it. Not me.

Yes, I am lost for words.

 

[humber]

(duplicate post deleted)

Shame. More Maximum Repetition Theorem gone to waste.

 

[GregLondon]

A diagram, and the effort to draw it may simplfy your experiment, and allow you to better see your own errors.

I write up a bunch of numbers for boundary layer stuff at 2390
http://www.internationalskeptics.com/forums/showpost.php?p=4373696&postcount=2390

humber disputes in #2394
http://www.internationalskeptics.com/forums/showpost.php?p=4373751&postcount=2394


I show drawing in #2411
http://www.internationalskeptics.com/forums/showpost.php?p=4373908&postcount=2411

You still haven't explained how the bottom two drawings in 2411, as described in text in 2390 are wrong, humber.

 

[humber]

I have actually written a couple of serious constructive posts also but it has been clear from the start that serious constructive posts is completely useless in a "conversation" with you.

I tried, I am sure of that.

1694 posts and you are either so dense that you don't understand relative motion and other concepts in physics or are you are just playing.

Not mutually exclusive.

By the way, I am still waiting for the answer for all my question I have asked you. Some questions.

What is a reference frame?

How can a treadmill be false?

Why a duck?

 

[humber]

I write up a bunch of numbers for boundary layer stuff at 2390
http://www.internationalskeptics.com/forums/showpost.php?p=4373696&postcount=2390
humber disputes in #2394
http://www.internationalskeptics.com/forums/showpost.php?p=4373751&postcount=2394
I show drawing in #2411
http://www.internationalskeptics.com/forums/showpost.php?p=4373908&postcount=2411
You still haven't explained how the bottom two drawings in 2411, as described in text in 2390 are wrong, humber.

#2411 has nothing to do with the boundary of the belt.
I have explained that the two generators may be much the same, but so what?
An palpable truth. An object dragged through the air, sees moving air much like the wind. That of itself, does not validate the method, or accuracy of that model.

 

[GregLondon]

Greg:

If the cart is 60% efficient and the max power it can get from the prop/wheel combination is 10 watts, it still has 6 watts to work with, and it can use those 6 watts to go faster than the wind.

Then the cart will not get to windspeed because that requires a conservation-busting transfer of 100%

We can pull a rope on a block and tackle and make something go faster than we pull it. We can push a lever and move something faster than we push the lever. but you insist that the wind can't push on a gear transferring power to the ground and make a device go faster than the wind?

It has nothing to do with being 100% effecient. It has to do with tranforming power to different force*velocities. Same power, same inefficiency, more velocity, less force.

 

[sol invictus]

Wait, was humber saying it was "A" for the belt-speed observer and "A" for the wind-speed observer or was it the other way around??

I don't think our alter-abled humber understands the difference. I think we can assume his answer (A) is for the "windspeed" observer, i.e. someone standing next to the treadmill and measuring the airspeed at different heights above it.

Which raises the question: what would someone moving along with the belt measure? What happens if we add the windspeed vector to picture A?

 

[GregLondon]

Greg:

I write up a bunch of numbers for boundary layer stuff at 2390
http://www.internationalskeptics.com/forums/showpost.php...postcount=2390
humber disputes in #2394
http://www.internationalskeptics.com/forums/showpost.php...postcount=2394
I show drawing in #2411
http://www.internationalskeptics.com/forums/showpost.php...postcount=2411
You still haven't explained how the bottom two drawings in 2411, as described in text in 2390 are wrong, humber.

#2411 has nothing to do with the boundary of the belt.

WHAT??? You're saying the numbers shown by the sensors on the tower are wrong? please correct by giving the "real" numbers.

Don't redraw anything. Keep the exact same scenario and the exact same drawing, just whiteout the numbers beside teh tower and indicate what those sensors should read.

 

[GregLondon]

Humber,

Regarding:

the scenario I drew in 2411,
the two scenarios in the bottom half of that picture,
described in text in post 2390,

question for you:

How would the truck/tower know which of the two scenarios it is in if all of its sensor data measures teh exact same values? Spedometer says 10 mph, wind speed indicators on the top of the tower say zero.

How is it the truck/tower can measure the exact same inputs and yet you insist that the treadmill is not a legitimate equivalent to running on teh ground?

How would the truck/tower even know there is a difference?

 

[humber]

Greg:



We can pull a rope on a block and tackle and make something go faster than we pull it. We can push a lever and move something faster than we push the lever. but you insist that the wind can't push on a gear transferring power to the ground and make a device go faster than the wind?

It has nothing to do with being 100% effecient. It has to do with tranforming power to different force*velocities. Same power, same inefficiency, more velocity, less force.

That is partially correct. MPT does not imply the absolute level of transfer but the amount of that transferred. It does say that the maximum will occur when the load and source match. This is why terminal velocity, happens.