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"sematics.. I don't recall mentioning boosters.. them things never got ear this far. But ok.."
Sigh...
"was a space shuttle main rocket re-entry"
The external fuel tank wasn't a rocket. It was a fuel tank. The boosters were the rockets that got it enough velocity to achieve orbit. The actual shuttle rockets (fed by the external fuel tank) were part of the shuttle and I have yet to see a video of a shuttle landing without its engines, so am assuming they didn't discard them over the Pacific. However, since you didn't take kindly to a polite and minor correction, I thought I'd just point that out.
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sematics..
I have to say I was initially confused when you said you saw "a space shuttle main rocket re-entry" from Mauna Kea. Most of the single stage or multi stage rockets launched from Florida drop those parts of the vehicle in the Atlantic Ocean. I had never heard of one traveling 3/4 of the way around the world as far as Hawaii. The external fuel tank does stay attached to the shuttle longer because as TomK said it fuels the on-board shuttle engines.
Just like your car has both an engine and a gas tank, the shuttle does too. Both parts are necessary to get you there, but they have different functions along the way.
Four people are in a room and seven leave. How many have to enter again before it's empty?
"I'm at that stage in life where I stay out of discussions. Even if you say 1+1=5, you're right - have fun." - Keanu Reeves
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"
Four people are in a room and seven leave. How many have to enter again before it's empty?"
You know, this is starting to bother me! I can think of several answers depending on what information is being left out or what assumptions are being made, or even the context. However, if this is a quantum mechanical metaphorical problem, the answer is one (or one-half of a person if you want to argue).
But I have the feeling this isn't to do with QM.
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I have the feeling this isn't to do with QM.
Yes, you're right.
It's a line from one of my Summer 2017 reads*, The Nothing That Is (A Natural History of Zero) by Robert Kaplan. The author was attempting to explain the difficulty humanity had in trying to understand and accept the concept of zero, and negative numbers.
People had counted for millennia, they could add and subtract with words or roman numerals, but the idea of Arabic numbers was a hard sell. And introducing zero as a placeholder for tens, hundreds, thousands, etc. met with even more resistance:
"The void was identified with evil."
I'm sure there are some, even today, depending on how they did in math class, who might agree.
Fortunately as you said "You know, this is starting to bother me!"
It bothered some others in the past too, which allowed us to progress into algebra, and everything else advanced mathematics has given us today, including our cell phones, computers, and even the ability to communicate via Punaweb.**
* Read here in Puna District
** Further gratuitous Puna reference
Four people are in a room and seven leave. How many have to enter again before it's empty?
"I'm at that stage in life where I stay out of discussions. Even if you say 1+1=5, you're right - have fun." - Keanu Reeves
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Thanks, HOTPE. I certainly wondered if it was to do with the concept of negative numbers (or even imaginary numbers!) but it was worded in such a way I thought it might be something different. However, it's definitely true that if you express the problem mathematically, then you need use negative numbers and have a concept of zero. Nice one, thanks for exercising my brain for a bit! Incidentally, if you're curious, my QM answer comes from the theory of Hawking radiation and virtual pairs.
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I guess the answer is 3 people...
if you wish to make an apple pie from scratch, you must first invent the universe..
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Math logic: 4-7+3=0
Language logic: if three people enter the room, how on earth can it be empty?
QM logic: did you influence the result by observing them enter the room?
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On July 11, 1991 I was on Isla Isabella in Mexico. Looking at totality with binoculars is something I'll never forget, seeing the prominences and corona. Very surreal place to be for the "great eclipse ".
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Four people are in a room and seven leave. How many have to enter again before it's empty?
Zero, it's already empty after the 4 people and 3 newborns left.
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quote:
Originally posted by TomK
Math logic: 4-7+3=0
Language logic: if three people enter the room, how on earth can it be empty?
QM logic: did you influence the result by observing them enter the room?
Tom, not so fast, First I want to know how the 7 people left when only 4 were in there in the first place.
Did you observe that before the 3 people entered?
Maybe they left at the speed of light and went back in time into some other dimension before they re-entered the room.
