Merged DDWFTTW in a “Real” Wind

[phunk]

Gee, Sol, you are a wizz.
First you write an equation around the "relative velocity" ( which is also the differential velocity, with a common mode velocity of the surface of the planet, but we are going to make that zero, aren't we now?), and the same equation, relabeled "closing velocity"

You then write an equation that says the closing velocity becomes zero when the distance, b = 0,

That distance never becomes 0. What, do you think two cars can magically drive through each other? Go back and read the problem again, the two cars pass each other a couple car lengths apart. So the closest they ever get to each other is a couple car lengths, that distance is b.

 

[humber]

Whoosh .....

That was the sound of basic vector addition flying over humber's head.

Electronics often involves vectors, and manipulation of poly-phase vectors and whole lot more . Electronics doesn't "do" much, and is greatly abstracted.
That makes the cart trivial to consider, and the posted equations a LOL

Here we have closing speed exactly the same as relative speed.
There is no "closing speed" related to distance.
Egg on face for guess who?

 

[humber]

That distance never becomes 0. What, do you think two cars can magically drive through each other? Go back and read the problem again, the two cars pass each other a couple car lengths apart. So the closest they ever get to each other is a couple car lengths, that distance is b.

Doh.

 

[humber]

"we" being me and other posters who mentioned in either this or other posts.

Windgrins

Your initial filibuster made pains to say you were impartial, but now part of "we".

 

[windgrins]

Sorry you don't seem to have it in you!

A reference, if you please. There is no closing velocity in this context.
Like Sol and Spork you are confusing a constantly changing distance with a constant speed.


No, it is black and white.


The distance is zero.


Try looking that up.


It was nonsense disguised as erudition, and tarted up with talk of dimensions, which makes no sense anyway. One dimensional cars. Might be difficult to measure that distance.


So, rises because the denser air replaces it.


The balloon is less dense, so has less gravitational force for the same volume.
That's how a ship floats.


More like Imperial Stormtrooper.


And after I pointed out that balloons may have lift due to the Magnus effect.
A face-saver.


No, even air takes time to accelerate. There are several means of calculating the horizontal velocity of a weather balloon, assuming it can be coaxed to fly horizontally without rising. The simplest, I would expect is to use Rayliegh's drag formula and then use the mass of the balloon to provide the time-constant t. Something like this: Vb = Vw - e-t/tau
The balloon will rise exponentially to Vw (but not reach it) and the time t will be related to the acceleration. That is because the driving force falls as the balloon approaches WS, so the acceleration will fall too.


All these "subtle" nuances....sure. A brute force and silly show provided by an office manager.
Those "tests" become forced when mathematical and theoretical skill are absent.


PE = m*g*h. A stationary NB balloon has a buoyancy force that is equal to the force of gravity upon it. For an object on top of a ladder, the ladder provides the opposing force. That object still has PE, and so does the balloon.


How about you didn't think about it until I mentioned it, and Spork put his foot in it?

Rhett has corrected you regarding the KE. Stand corrected, rather than fall over yourself with contradictory exudes, Windgrins.

OK, I won't insult you but I won't respond anymore either since you don't appear to value the effort. If the other posters (having read my tedious post earlier) have any question or comment, feel free.

Regards,

WindGrins,

 

[spork]

OK, I won't insult you but I won't respond anymore either since you don't appear to value the effort. If the other posters (having read my tedious post earlier) have any question or comment, feel free.

Your post was right on the money. My only question is why you'd make that effort on someone that never had the slightest chance of understanding it - when the only possible response would be an insult for your efforts?

 

[humber]

OK, I won't insult you but I won't respond anymore either since you don't appear to value the effort. If the other posters (having read my tedious post earlier) have any question or comment, feel free.

Regards,

WindGrins,

The post was busted flat on each point I could separate from the fantasy physics, Windgrins. Lots of schoolboy errors from the master.

 

[humber]

Your post was right on the money. My only question is why you'd make that effort on someone that never had the slightest chance of understanding it - when the only possible response would be an insult for your efforts?

Got an equation for you magic balloon, Spork?
It that the same test to which you subject "PhD's who work at your place" ?
Don't bank on the power project.

 

[phunk]

Didn't you already post the equation humber? The one that showed that any velocity difference between the air and the balloon resulted in drag?

 

[windgrins]

WindGrins motivations

Your post was right on the money. My only question is why you'd make that effort on someone that never had the slightest chance of understanding it - when the only possible response would be an insult for your efforts?

My purpose for being here is to learn things I didn't know before. By being clear (in this case, tediously clear) I felt that I could potentially clarify to everyone the basis of a lot of issues with posts so that we didn't have to nibble away at them.

My guess is that Humber ain't gonna change and we'll never see a "Top Secret" cart that has any merit whatsoever and finally his idea of "trashing you with NALSA data will probably have as much merit as his elementary physics. I'll probably continue to read many of the posts for the giggles.

Finally, Humber has a hard time insulting me as his every post with physics content so far has pretty clearly validated his errors in understanding to anybody I think may in a position to judge. His dismissals and clarified retorts can't do anything but clarify my position's merit.

Regards,

WindGrins

 

[humber]

Finally, Humber has a hard time insulting me as his every post with physics content so far has pretty clearly validated his errors in understanding to anybody I think may in a position to judge. His dismissals and clarified retorts can't do anything but clarify my position's merit.

Fantasy. All Spork's mistakes from potential energy to "closing velocity" exposed for what they are. Your own reference say so, and so does Rhett.
I am waiting for TAD to tell why they can't do the airport test you suggested.

 

[spork]

My guess is that Humber ain't gonna change and we'll never see a "Top Secret" cart

That's more than a safe bet.

his idea of "trashing you with NALSA data will probably have as much merit as his elementary physics.

I enjoy his giddiness about having managed to get the data he thinks I'm so fearful he now has - particularly given the fact that I gave it the thumbs up to go ahead and send that data.

 

[windgrins]

One obvious Fallacy

Since Humber can write pithy nonsense replys faster than I can write reasoned explanations, I think I will offer this final example to the audience and rest my case. It's just too tedious to take this any further.

The balloon is less dense, so has less gravitational force for the same volume.
That's how a ship floats.

If the balloon had less density than the air it displaces, it wouldn't be Neutral Buoyancy. This is how submarines hover underwater (not how ships float) since they are Neutrally Buoyant in their medium also.

Neutrally Buoyant balloons don't float on top of the atmosphere. They hover in it.

Enough explained.

WindGrins

 

[mender]

You presented two scenarios which are not transforms of each other with the intent of "disproving" that they are transforms.

If you were in a car heading for a stationary truck, would you apply the brakes?

Yes, or turn the wheel.

If you were in a stationary car, with a truck heading towards you, would you put your foot on the brake?

No, I'd move out of the way.

As usual, you imply that changing the frames changes the relative motion of the objects in the frame. It doesn't. If applying the brakes or turning the wheel of one particular vehicle causes the collision to be avoided (or not) in one frame of reference, it will also have the exact same affect in any other frame. The relative speed of the observer doesn't affect what happens.

Choose a scenario; the answer will be the same regardless of the FOR.

Congratulations on producing another bunch of replies to a nonsensical question. Kick the physics antpile and watch the ants scurry. You play the game well, but why do you bother? Are you really that desperate for attention since your pet mouse died?

 

[CORed]

Fantasy. All Spork's mistakes from potential energy to "closing velocity" exposed for what they are. Your own reference say so, and so does Rhett.
I am waiting for TAD to tell why they can't do the airport test you suggested.

He already did. You just weren't bright enough to understand it.

 

[humber]

If the balloon had less density than the air it displaces, it wouldn't be Neutral Buoyancy. This is how submarines hover underwater (not how ships float) since they are Neutrally Buoyant in their medium also.

It doesn't sound like you do want to learn, Windgrins.
They can sit on the seabed, pump out water, and rise. They gain PE from being raised in the gravitational field. That represents the work done by the buoyancy force.

"When a vector field represents force, the line integral of a vector field represents the work done by a force moving along a path, and under this interpretation conservation of energy is exhibited as a special case of the fundamental theorem of calculus"

 

[humber]

He already did. You just weren't bright enough to understand it.

Oh, I understood it all right. The pre-match excuse that prevents the match.
The "keen experimenters" have lost their enthusiasm for "real science" over theory.
One has to ask why the belt has a minimum speed, that does not bother the real cart. It's because the latch mechanism will fail when the belt speed becomes too low.

 

[windgrins]

Humber is Correct (sort of) for all the wrong reasons!

PE = m*g*h. A stationary NB balloon has a buoyancy force that is equal to the force of gravity upon it. For an object on top of a ladder, the ladder provides the opposing force. That object still has PE, and so does the balloon.

Humber slipped up and became correct (sort of!)

For a stationary (what would otherwise be an NB) sphere sitting on top of a ladder in a vacuum chamber, It does indeed have Potential Energy.

This is a little far away from the question at hand with a NB Balloon in an equivalent medium.

I use this example to illustrate to Spork, the potential benefit to some of the posters, of utilizing one of Humber's fundamentally wrong answers to illustrate the exact opposite to what is stated as the correct understanding.

Regards,

WindGrins

 

[windgrins]

I pass the baton!

It doesn't sound like you do want to learn, Windgrins.
They can sit on the seabed, pump out water, and rise. They gain PE from being raised in the gravitational field. That represents the work done by the buoyancy force.

"When a vector field represents force, the line integral of a vector field represents the work done by a force moving along a path, and under this interpretation conservation of energy is exhibited as a special case of the fundamental theorem of calculus"

If anyone wants to discuss the obvious tangent from the question in this one, you are welcome!

I formally pass the baton!

Regards,

WindGrins

 

[jadebox]

Really? I must have missed that. Can you post a link or give me an idea on about what page I might find that explanation?

It's in pretty much every post on the subject except those made by humber.

It's also obvious. As I've said a few times, for the balloon to travel at less than the speed of the wind, it would have to have some source of energy to allow it to push against the wind. And, it would have to somehow know which way to push.

As someone else pointed out, for a neutrally bouyant balloon, there's really no difference between the air on the inside of the balloon and the air around it which is another observation that makes it obvious that a balloon travels at wind speed.

-- Roger