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Picture of konata88
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Slightly different question.

Is the answer above true always? Or only true if A is filled beyond a certain volume?




"Those who would give up essential Liberty, to purchase a little temporary Safety, deserve neither Liberty nor Safety." - B.Franklin
"Wrong does not cease to be wrong because the majority share in it." L.Tolstoy
 
Posts: 6714 | Location: In the gilded cage | Registered: December 09, 2007Reply With QuoteReport This Post
Lost
Picture of kkina
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quote:
Originally posted by konata88:
Slightly different question.

Is the answer above true always? Or only true if A is filled beyond a certain volume?

It is definitely not always true. The outcome can be altered with slightly different starting conditions. From the Wiki article...

quote:
At large extensions, the pressure inside a natural rubber balloon once again goes up. This is due to a number of physical effects that were ignored in the James/Guth theory: crystallization, imperfect flexibility of the molecular chains, steric hindrances and the like.[5] As a result, if the two balloons are initially very extended, other outcomes of the two-balloon experiment are possible,[1] and this makes the behavior of rubber balloons more complex than, say, interconnected soap bubbles.[4] In addition, natural rubber exhibits hysteresis: the pressure depends not just on the balloon diameter, but also on the manner in which inflation took place and on the initial direction of change. For instance, the pressure during inflation is always greater than the pressure during subsequent deflation at a given radius. One consequence is that equilibrium will generally be obtained with a lesser change in diameter than would have occurred in the ideal case.[1] The system has been modeled by a number of authors,[6][7] for example to produce phase diagrams[8] specifying under what conditions the small balloon can inflate the larger, or the other way round.

The answer is correct for the parameters I set forth in the OP.
 
Posts: 10410 | Location: SF Bay Area | Registered: December 11, 2003Reply With QuoteReport This Post
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Picture of Sig Sauer Kraut
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Ha. I guessed the correct answer. The way I thought about it was that a balloon usually gets easier to inflate once you get past a certain point. That, and I figured it was a trick question and would be the least obvious answer. :-)
 
Posts: 396 | Registered: January 04, 2008Reply With QuoteReport This Post
Lost
Picture of kkina
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^^Excellent! If you watch the video, he gives what *may* be a clue when he inflates the larger balloon, taking obvious effort on the first breath, and a much easier time on the second exhale. Hard to tell if this was intentional or not.

You never know about those trick questions. Is he trying to smokescreen the obvious answer and make you pick the most bizarre choice, or is it really a tricker?
 
Posts: 10410 | Location: SF Bay Area | Registered: December 11, 2003Reply With QuoteReport This Post
Oh stewardess,
I speak jive.
Picture of 46and2
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quote:
Originally posted by Gustofer:
Answer B. Or...42.

Definitely 42.

(I guessed they'd equalize, too).

Cool problem.
 
Posts: 21693 | Registered: March 12, 2004Reply With QuoteReport This Post
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There was a pretty good clue at the beginning of this.

quote:
Originally posted by kkina:
Two child's party balloons, initially identical....


But not identical any more. The balloon has changed.
 
Posts: 283 | Registered: September 10, 2009Reply With QuoteReport This Post
Step by step walk the thousand mile road
Picture of Sig2340
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Then there's that there pervert equation to consider.



Nice is overrated

And people wonder why I carry a SIG P320

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Posts: 26096 | Location: Loudoun County, Virginia | Registered: May 17, 2006Reply With QuoteReport This Post
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I had that happen once with a condom. Damn thing started expanding and almost sucked my testicals up inside me.


------------------------------
"They who would give up essential liberty to obtain a little temporary safety, deserve neither liberty nor safety."
- Benjamin Franklin

"So this is how liberty dies; with thunderous applause."
- Senator Amidala (Star Wars III: Revenge of the Sith)
 
Posts: 920 | Location: Southwest Ohio | Registered: October 07, 2011Reply With QuoteReport This Post
Muzzle flash
aficionado
Picture of flashguy
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I chose #4 (air flows from smaller to larger balloon) upon first reading the question (before reading any of the--initially incorrect--responses of others). I confess that I remember seeing a demonstration of the effect when I was in high school physics class in 1953.

flashguy




Texan by choice, not accident of birth

When they ask me, "Paper or plastic?" I just say, "Doesn't matter to me. I am bi-sacksual."
 
Posts: 18924 | Location: Dallas, TX | Registered: May 08, 2006Reply With QuoteReport This Post
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Personally, I believe you're the victim of a hoax.

The part of the video where he opens the valve is actually running backwards. Notice that he carefully ensured that his face was not visible during that portion. It would be difficult to hide that his speaking wouldn't match the audio.



God's mercy: NOT getting what we deserve!
God's grace: Getting what we DON'T deserve!

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Posts: 689 | Location: Fayette County, GA | Registered: April 14, 2014Reply With QuoteReport This Post
Lost
Picture of kkina
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quote:
Originally posted by Yellow Jacket:
Personally, I believe you're the victim of a hoax.

The part of the video where he opens the valve is actually running backwards. Notice that he carefully ensured that his face was not visible during that portion. It would be difficult to hide that his speaking wouldn't match the audio.


Google "2 balloon experiment". This is a well-known phenomenon. I doubt that there could be so many people in on a hoax.

As far as the video running backwards, where do you see that? Try searching this on Youtube; are all those videos running backwards?
 
Posts: 10410 | Location: SF Bay Area | Registered: December 11, 2003Reply With QuoteReport This Post
Plowing straight ahead come what may
Picture of Bisleyblackhawk
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When the valve is opened between the two balloons...the larger balloon, due to its dominant nature, actually sucks the air out of the weaker smaller balloon...much the same way a cat (being the dominant creature) can suck the breath from a sleeping human (the weaker subservient creature)...it's just nature.

I actually expected them to balance out until both were approx. the same size...cool post Smile


********************************************************

"we've gotta roll with the punches, learn to play all of our hunches
Making the best of what ever comes our way
Forget that blind ambition and learn to trust your intuition
Plowing straight ahead come what may
And theres a cowboy in the jungle"
Jimmy Buffet
 
Posts: 7354 | Location: Southeast Tennessee...not far above my homestate Georgia | Registered: March 10, 2010Reply With QuoteReport This Post
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I can give you a real world example of the principles involved.

When repairing a bicycle tire you need to inflate the tube slightly to give it enough shape to get it into the tire to avoid a pinch flat. Care is required since the tube very definitely gets easier to inflate as you put more air into it. I use natural rubber tubes and it is very easy to blow one out, they will form a bulge, look like a cheap toy balloon and pop.
 
Posts: 3698 | Location: Citrus County Florida | Registered: October 13, 2008Reply With QuoteReport This Post
Lost
Picture of kkina
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^^Good example! Thinking about it, it does sound right when I had a bicycle.
 
Posts: 10410 | Location: SF Bay Area | Registered: December 11, 2003Reply With QuoteReport This Post
I have not yet begun
to procrastinate
Picture of KMitch200
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quote:
Originally posted by Bisleyblackhawk:
I actually expected them to balance out until both were approx. the same size...cool post Smile

Yep, me too! Cool experiment.


--------
After the game, the King and the pawn go into the same box.
 
Posts: 2243 | Location: AZ - West side of the valley | Registered: October 26, 2006Reply With QuoteReport This Post
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Anyone who's made a poodle balloon animal should've been able to answer this correctly.

What? No one makes balloon animals???


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Charter member of the vast, right-wing conspiracy
 
Posts: 1134 | Registered: June 25, 2010Reply With QuoteReport This Post
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