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| james |
 Jan 31 2008, 08:22 AM
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#1
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  Group: Super Administrators Posts: 3296 Joined: 2-March 01 From: Surrey, UK Member No.: 13  |
Dragging up the past a bit - TV show Mythbusters ran it's much anticipated episode with a practical experiment version of this question on it a couple of nights ago over in the US.
I don't know when it will come on over here but for the curious Kottke liveblogged it and also links to another good explanation from a guy with a Sc.D. in Nuclear Science and Engineering (whatever that is). And for the hard of attention and understanding - yes of course it takes off.  -------------------- "We are number one, all others are number two or lower!" - The Sphinx, Mystery Men
"A computer without a Microsoft operating system is like a dog without bricks tied to its head" - annon "What a terrible thing to have lost one's mind. Or not to have a mind at all. How true that is." - Dan Quayle |
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| james |
Mar 3 2008, 03:16 PM
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#2
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Group: Super Administrators Posts: 3296 Joined: 2-March 01 From: Surrey, UK Member No.: 13 |
Imagine you are holding a matchbox car (the kind with the spinny wheels which just go around - not the kind with the wind up 'motor' in it) on a treadmill - by the logic you have outlined above you would not be able to push the car along the treadmill (and by push I mean holding on to it and moving your hand and therefore the model forward). But obviously you could do that - now substitute the plane for the car and the engine power for your arm and voila!
Even if the treadmill was going at a gazzillion miles an hour you could hold the car on it (the unpowered wheels would just rotate at the same speed as the treadmill). When you push it forward they would rotate at the speed of the treadmill plus the forward speed you are applying - they are for all intents and purposes irrelevant. -------------------- "We are number one, all others are number two or lower!" - The Sphinx, Mystery Men
"A computer without a Microsoft operating system is like a dog without bricks tied to its head" - annon "What a terrible thing to have lost one's mind. Or not to have a mind at all. How true that is." - Dan Quayle |
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| Egg Designer |
Mar 3 2008, 03:25 PM
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#3
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 Group: Full Members Posts: 458 Joined: 27-May 02 From: Somewhere just left of sanity Member No.: 88 |
QUOTE(James @ Mar 3 2008, 04:16 PM)  Imagine you are holding a matchbox car (the kind with the spinny wheels which just go around - not the kind with the wind up 'motor' in it) on a treadmill - by the logic you have outlined above you would not be able to push the car along the treadmill (and by push I mean holding on to it and moving your hand and therefore the model forward). But obviously you could do that - now substitute the plane for the car and the engine power for your arm and voila! Even if the treadmill was going at a gazzillion miles an hour you could hold the car on it (the unpowered wheels would just rotate at the same speed as the treadmill). When you push it forward they would rotate at the speed of the treadmill plus the forward speed you are applying - they are for all intents and purposes irrelevant. But in this hypothetical situation, if no thrust was being applied and you turn the treadmill on, would the plane go backwards? -------------------- Aoccdrnig to rscheearch at Cmabrigde Uinervtisy, it deosn't mttaer in waht oredr the ltteers of a wrod are, the olny iprmoetnt tihng is taht the frist and lsat ltteer be at the rghit pclae.
The rset can be a total mses and you can sitll raed it wouthit porbelm. Tihs is bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe. Fcuknig amzanig huh |
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Posts in this topic
James Plane on a conveyor revisited Jan 31 2008, 08:22 AM
camsmith You could just have used his graphic... :devil: :... Jan 31 2008, 10:39 AM jamie I just want to publicly state at this point
I st... Feb 22 2008, 10:19 AM Jeffers Brando, Brando, Brando......
If you strapped a ro... Feb 25 2008, 10:20 AM
paul If you strapped a rocket to my arse when I was ru... Feb 25 2008, 10:53 AM James
Reading that lit up a bulb for me - I never consi... Feb 27 2008, 08:48 AM jamie no, I can see how you are thinking.. Its just if t... Feb 29 2008, 03:16 PM Jeffers Your wrong
no, I can see how you are thinking.. ... Feb 29 2008, 05:23 PM paul no, I can see how you are thinking.. Its just if ... Feb 29 2008, 09:08 PM James Ok - as long as you didn't think we meant it s... Mar 1 2008, 10:46 AM jamie that only makes sense if the plane were suspended ... Mar 2 2008, 12:09 PM Emily It took my a while to get this but there was one e... Mar 2 2008, 04:12 PM jamie dont get me wrong, that makes sense. But there is ... Mar 2 2008, 06:15 PM Emily the engine is pulling the plane through the air - ... Mar 2 2008, 10:22 PM Jeffers Emily is correct.
:tongue:
the engine is pull... Mar 3 2008, 12:24 PM jamie Its not that I dont understand what you are saying... Mar 3 2008, 02:31 PM jamie Exactly! Couldnt find a way of phrasing it.
... Mar 3 2008, 06:40 PM Emily I think this has got to the point where without se... Mar 3 2008, 09:33 PM camsmith Jamie, I think you are forgetting one simple thing... Mar 3 2008, 10:24 PM jamie if the plane was floating i would agree.
There i... Mar 4 2008, 05:34 PM camsmith If you want to take that line, then there is a sim... Mar 5 2008, 04:35 AM jamie Ok, lets revisit the rope scenario
In a relevant ... Mar 5 2008, 05:59 PM Jeffers Your wrong
Accept it and move on with your life.
... Mar 6 2008, 05:50 PM Emily I sorry I can't wait - Jamie you've missed... Mar 6 2008, 08:08 PM paul Did anyone see the Motor racing? Mar 7 2008, 06:08 PM jamie With or without the wheels the result would be the... Mar 8 2008, 03:05 PM Egg Designer The rope theory is not relevant in this argument a... Mar 12 2008, 12:11 PM Jeffers The plane will only take off if there is airflow o... Mar 13 2008, 10:20 AM jamie
Your wrong
Accept it and move on with your life.... Mar 13 2008, 01:13 PM Jeffers Thats impossible.
Your wrong
Accept it and mov... Mar 14 2008, 04:25 PM Egg Designer OK, does that mean we are all in agreement now the... Mar 13 2008, 03:06 PM Emily :mad: Your all Ghaaayyy! and wrong! :ha... Mar 16 2008, 11:36 AM Jeffers
:mad: Your all Ghaaayyy! and wrong! :h... Mar 17 2008, 08:51 AM |
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