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Title: Brainteaser: There's an airplane on the runway..
Source:
Elsewhere
URL Source: http://www.someplaceelse.com
Published: Dec 1, 2005
Author: I have no idea
Post Date: 2005-12-01 01:10:02 by Jhoffa_
Keywords: Brainteaser:, airplane, runway..
Views: 1047
Comments: 202
Imagine a plane is sat on the beginning of a massive conveyor belt/travelator type arrangement, as wide and as long as a runway, and intends to take off. The conveyer belt is designed to exactly match the speed of the wheels at any given time, moving in the opposite direction of rotation. There is no wind. Can the plane take off?
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#152. To: All (#145)
I'm re-thinking this. Whatever thrust is produced by the engines would be applied to the mass of the plane, seems the wheels and conveyor are immaterial.
The epitomy of madness or sarcasm.
"Thinking that women have a corner on caring is delusional" - A Man not thinking with his dick
Yeah, so what? Forget physics, in the world of this brain-teaser the cbelt has to achieve infinite speed to compensate. The wheels are spinning, they must be there... And I'm optimistic. See, I think you can be realistic and optimistic at the same time. I'm optimistic we'll achieve -- I know we won't achieve if we send mixed signals. I know we're not going to achieve our objective if we send mixed signals - gwbush
Thank you, I was only going for honest...
And I'm optimistic. See, I think you can be realistic and optimistic at the same time. I'm optimistic we'll achieve -- I know we won't achieve if we send mixed signals. I know we're not going to achieve our objective if we send mixed signals - gwbush
If you close your left eye and cycle the closing and opening of the right eye you can see Jesus....
"Thinking that women have a corner on caring is delusional" - A Man not thinking with his dick
You can do that with these new visual mousees to, just hold it upside down and look straight into the light...
And I'm optimistic. See, I think you can be realistic and optimistic at the same time. I'm optimistic we'll achieve -- I know we won't achieve if we send mixed signals. I know we're not going to achieve our objective if we send mixed signals - gwbush
I think you made it just in time. Look what I found. When prosperity comes, do not use all of it. - Confucious The same can be achieved using phosphines or imprinted images on the retina via black in white images...pretty neat stuff. But that would lack meaning among those on the other side.
"Thinking that women have a corner on caring is delusional" - A Man not thinking with his dick
EXCELLENT. Started to think of some dynamics classes - that cleared the fog.
It seems we are now on the same page with both brainteasers now. Whew!
When prosperity comes, do not use all of it. - Confucious Excellent analysis!
God is always good! The tires would burn off, then the wheels would break off, due to the massive heat generated by the race to infinite speeds brought about by the unreal exact matching of the rotational speed of the airplane wheels by the conveyer belt, before the plane had a chance to get enough speed to get airborne. The plane would then come to a skidding halt on the runway, it would not take off. I gave you an excellent clue why your hypothesis was wrong, but it seemed you were too busy calling other people’s analysis “Sad, really sad”, to notice.
God is always good! So you read Soren's post huh? LOL! Just kidding! Good analysis, except for the exploding part, I think the wheels would break off before that happened, thus causing the conveyer belt to stop.
God is always good! in a car, true in a plane, nope
Adolf Hitler... "What luck for rulers that men do not think." John F. Kennedy... "Those who make peaceful revolution impossible will make violent revolution inevitable." bingo people can change thanks God, I needed that
Adolf Hitler... "What luck for rulers that men do not think." John F. Kennedy... "Those who make peaceful revolution impossible will make violent revolution inevitable." Like A.J. says, "we're in a Twilight episode. Enjoy, you can get out during the commercial.
Adolf Hitler... "What luck for rulers that men do not think." John F. Kennedy... "Those who make peaceful revolution impossible will make violent revolution inevitable." Twilight Zone
Adolf Hitler... "What luck for rulers that men do not think." John F. Kennedy... "Those who make peaceful revolution impossible will make violent revolution inevitable." then where are the extra spins of the landing gear wheels going, mister smartguy? Assuming solid construction and a magical fuel supply that plane is stuck on that conveyor belt forever.
And I'm optimistic. See, I think you can be realistic and optimistic at the same time. I'm optimistic we'll achieve -- I know we won't achieve if we send mixed signals. I know we're not going to achieve our objective if we send mixed signals - gwbush
This shall be my last post on this subject (for a least 10 minutes). Of the four aerodynamic forces, two are initially involved in a plane sitting for takeoff: weight and thrust. A high bypass gas turbine does not blast a plane down the runway like a bullet out of a .357 pistol. The pilot throttles and the thrust must overcome the weight of the plane to move the plane forward. As the plane--STARTING out SLOWLY at first--gains speed, lift and drag come into play as the plane approaches take off speed. Then, it is lift which eventually pulls the plane off the ground. The weight of the plane sits on the tires. As thrust is applied, the weight of the plane is pushed along ON THE TIRES if on a STATIONARY surface. If the surface on which the tires (weight of the plane) sits is moving against the rotation of the tires while perfectly matching the speed of the tires, the plane cannot and shall not move. Intial momentum could NEVER be reached to make the plane move. Therefore, it could NEVER reach take off (lift) speed. Again, high bypass gas turbines are NOT rocket engines.
Why should we hear about body bags and deaths. Oh, I mean, it's not relevant. So why should I waste my beautiful mind on something like that? -- Big Mama Bush
I don't know what an extra spin is but, the landing gear are going with the plane... up, up and away.
Adolf Hitler... "What luck for rulers that men do not think." John F. Kennedy... "Those who make peaceful revolution impossible will make violent revolution inevitable." You need to watch the fan on the skateboard movie I posted earlier. I don't know why you are so hung up on the type of engine. It either supplies thrust or it does not. The axle the wheels are mounted on is designed to be as frictionless as possible. How is a frictionless device going to counter the forward thrust?
When prosperity comes, do not use all of it. - Confucious It has nothing to do with thrust or friction since the wheels of the airplane would have to remain motionless in order to satisfy the requirement about the conveyor belt counter rotating in opposite direction...
And I'm optimistic. See, I think you can be realistic and optimistic at the same time. I'm optimistic we'll achieve -- I know we won't achieve if we send mixed signals. I know we're not going to achieve our objective if we send mixed signals - gwbush
The conveyer belt is designed to exactly match the speed of the wheels at any given time, moving in the opposite direction of rotation. As the plane reaches 1 mph relative to the ground (not the belt), let's say its tires are spinning at 2 mph (the outside edge). The conveyor belt must therefore be spinning at 2 mph (the upper edge) to match. All conditions are met. As the plane reaches 100 mph relative to the ground (not the belt), let's say its tires are spinning at 200 mph (the outside edge). The conveyor belt must therefore be spinning at 200 mph (the upper edge) to match. All conditions are met. Why the need for infinite rotational speed of the tires? There is no need whatsoever for the speed the tires spin at to be related in any way to the speed the plane is moving. You've got a skateboard sitting on a conveyor belt. The speed that the wheels spin has nothing to do with the speed of the skateboard. Further, the skateboard has a fan sitting on top of it. Nothing is going to counter that force. Picture the inside of the skateboard's ball bearing axles. Picture me accidentally stepping on a skateboard without knowing it is there. You may before it is over, lol. Perhaps you see me at the top of a tall flight of stairs. Now picture how frictionless I picture those wheels once I've reached the bottom. Ouch! Can't say I blame you but I'm not changing my opinion on this.
When prosperity comes, do not use all of it. - Confucious Bogus. The fan driven skateboard: 1) is moving (gains momentum) before the paper is pulled out from under it; 2) the speed of the paper and the skateboard wheels is not the same and uniform; and, 3) its weight is transferred to the stationary floor under the paper.
Why should we hear about body bags and deaths. Oh, I mean, it's not relevant. So why should I waste my beautiful mind on something like that? -- Big Mama Bush
I think I cover that in my last post. I caught on to why some seem to see a paradox here. The speed of rotation of the wheels must match the speed of the rotation of the conveyor belt, but that does not imply that speed is in any way related to the speed of the plane down the runway. Part of the problem is that rotational speeds really shouldn't be measured in miles per hour, but rather in degrees of rotation per hour. That's what seemingly creates the paradox here. I'd say the brainteaser is a bit poorly worded in that regard.
When prosperity comes, do not use all of it. - Confucious It wouldn't. It couldn't: Thread Rule #1: The conveyer belt is designed to exactly match the speed of the wheels at any given time, moving in the opposite direction of rotation.
And I'm optimistic. See, I think you can be realistic and optimistic at the same time. I'm optimistic we'll achieve -- I know we won't achieve if we send mixed signals. I know we're not going to achieve our objective if we send mixed signals - gwbush
And keep in mind it says exactly, so let's not hear any whiney explanations about lag time.
And I'm optimistic. See, I think you can be realistic and optimistic at the same time. I'm optimistic we'll achieve -- I know we won't achieve if we send mixed signals. I know we're not going to achieve our objective if we send mixed signals - gwbush
Bogus? 1) Are you trying to imply that the skateboard would not have moved if the fan had been sitting on it and then turned on? Really? You can't be serious. The skateboard has very frictionless tires. I know. I have accidentally stepped on one in the past, lol. 2) You can clearly see in the video that the speed at which the paper was pulled in no way impacted the speed of the skateboard. By not having it the same and uniform it merely makes the point stronger. The paper conveyor belt had no impact on the speed of the skateboard at numerous different speeds. 3) Of course the weight is transferred to the stationary floor under the paper. That's just like any conveyor belt would be.
When prosperity comes, do not use all of it. - Confucious what else needs to be said tires, wheels, conveyer belt... all irrelevant
Adolf Hitler... "What luck for rulers that men do not think." John F. Kennedy... "Those who make peaceful revolution impossible will make violent revolution inevitable." It wouldn't. It couldn't: Thread Rule #1: The conveyer belt is designed to exactly match the speed of the wheels at any given time, moving in the opposite direction of rotation. There is nothing stopping the plane from moving forward. As the wheels begin to turn, the conveyor belt "exactly" matches the speed of the wheels, whatever that speed ends up being. There is no inconsistency here.
When prosperity comes, do not use all of it. - Confucious The wheels could never move from their their original stop position, any movement they make is counteracted by The Belt. That's the rules, man.
And I'm optimistic. See, I think you can be realistic and optimistic at the same time. I'm optimistic we'll achieve -- I know we won't achieve if we send mixed signals. I know we're not going to achieve our objective if we send mixed signals - gwbush
What does this have to do with this thread?
God is always good! Airplanes. I'm pinging Skydrifter to the thread, because he may be able to explain to some folks how aircraft function, where myself, I just want to beat half of the people to death on this thread with the back of a shovel because they're so stupid.
That's not what it says. The conveyer belt is designed to exactly match the speed of the wheels at any given time, moving in the opposite direction of rotation. If the wheels are rotating clockwise, then the conveyor belt is rotating counterclockwise. If the outside edge of a wheel is turning at 10 mph, then the outside edge of the conveyor belt is merely turning at 10 mph in the opposite direction. Therefore, there is no slippage between the wheels and the belt at any given time.
When prosperity comes, do not use all of it. - Confucious You are a magician. You are going to do the old pull the tablecloth out from underneath the plates trick. Think of the tablecloth as a conveyor belt. You are a bit worried that some of those plates might choose to stick to the tablecloth and you are really looking to amaze your friends. You decide to mount little ball bearing wheels under each plate to reduce the friction. Good job! You did it! All the plates stayed right in place during the entire pulling of the cloth and you just kept pulling. Infinitely! You thought ahead and got one heck of a long table cloth. The plates just stayed right there on the table. Well done. How did the trick work? Well, you simply couldn't transfer any of the table cloth's (the conveyor belt) energy to the plates. There was a frictionless layer protecting them, in the form of the frictionless ball bearings making up the wheels, much like the nearly frictionless axles of the plane. Oh sure, the wheels on the plates spun big time but the plates never did move. You tried the trick later that night by pulling the table cloth twice as hard. You saw no difference. You have determined that the table cloth being pulled was absolutely irrelevant to where the plates would be. Next up, putting little fans on top of the plates in hopes they actually move. They will. They're sitting on frictionless ball bearing wheels. Once that is complete, it is off to impress your friends with the famous yank the tablecloth out from underneath moving plates trick.
When prosperity comes, do not use all of it. - Confucious but from a dead stop, the plane would never be allowed to start moving. Can the plane take off? Does "sat on the beginning of" mean, for our purposes, in a state of rest before we started experimenting on it?
And I'm optimistic. See, I think you can be realistic and optimistic at the same time. I'm optimistic we'll achieve -- I know we won't achieve if we send mixed signals. I know we're not going to achieve our objective if we send mixed signals - gwbush
If the outside edge of the conveyer belt is turning at 10 MPH, and the plane is moving at 10 MPH then the rotational speed of the wheels would be 20 MPH. But the conveyer belt is suppose to match the rotational speed of the airplane wheels in this fictional situation. So it must therefore increase its speed until it matches the speed of the airplane wheels, which it can't do if the plane is moving, which it will be if the engines are being revved up. So the airplane wheels and conveyer belt would continue to increase in speed at a very high rate of acceleration until the wheels of plane burn and break off. This is my last post on this fictional issue; there are more important things to talk about, such as the explosives used to take the WTC towers down on 9/11.
God is always good! Here is the condition that must be met. The conveyer belt is designed to exactly match the speed of the wheels at any given time, moving in the opposite direction of rotation The braintwister does not ask the conveyer belt to match the "rotational speed", just the speed. That part of the braintwister is vague and open to many interpretations unfortunately. What part of the tire? Relative to what? The bottom edge of the tire touching the conveyer belt, as seen from the control tower, is moving at 10 MPH backwards up the runway in your example (20 MPH backwards, 10 MPH forwards due to the plane). That's the speed I see the conveyor belt attempting to match. I have been down your path a few times myself, hemming and hawing about what was intended. Further, rotational speed is given in RPM, not miles per hour. In order for the conveyor belt to match rotational speed it would have to rotate once each time the wheel did. I don't think that was intended.
When prosperity comes, do not use all of it. - Confucious Yeah, I'd say so.
When prosperity comes, do not use all of it. - Confucious
Comments (192 - 202) not displayed.
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#153. To: Dakmar (#151)
we have very few runways higher than 80,000 feet anyway, and only a couple of them are testing conveyor belt technology.
#154. To: timetobuildaboat (#150)
Are you mental?
#155. To: timetobuildaboat (#153)
The epitomy of madness or sarcasm.
#156. To: Dakmar (#154)
Forget physics, in the world of this brain-teaser the cbelt has to achieve infinite speed to compensate. The wheels are spinning, they must be there...
#157. To: timetobuildaboat (#156)
#158. To: tom007 (#152)
I'm re-thinking this. Whatever thrust is produced by the engines would be applied to the mass of the plane, seems the wheels and conveyor are immaterial.
The nation is prosperous on the whole, but how much prosperity is there in a hole? - Will Rogers
There are 9,000 hedge funds out there. There aren't that many smart people in the world. - Michael Driscoll, a trader at Bear Stearns & Co. in New York
Some days you just want to pull out the Bonehead Stick and beat people senseless. - mirage
#159. To: Dakmar (#157)
You can do that with these new visual mousees to, just hold it upside down and look straight into the light...
#160. To: markm0722 (#158)
#161. To: tom007 (#160)
EXCELLENT. Started to think of some dynamics classes - that cleared the fog.
The nation is prosperous on the whole, but how much prosperity is there in a hole? - Will Rogers
There are 9,000 hedge funds out there. There aren't that many smart people in the world. - Michael Driscoll, a trader at Bear Stearns & Co. in New York
Some days you just want to pull out the Bonehead Stick and beat people senseless. - mirage
#162. To: Soren (#110)
"It was an interesting day." - President Bush, recalling 9/11 [White House, 1/5/02]
#163. To: wakeup (#75)
I stand by what I have written. I have confidence in my understanding.
"It was an interesting day." - President Bush, recalling 9/11 [White House, 1/5/02]
#164. To: Neil McIver (#111)
"It was an interesting day." - President Bush, recalling 9/11 [White House, 1/5/02]
#165. To: Dakmar (#149)
For the sake if this question, yes they are. It is mathematically impossible that the plane could move forward while in contact with cvbelt, the landing gear wheels are in fact solidly attached to the airframe, and are only moving forward to compensate for the rearward movement of conveyor belt. It says so right at the top! :)
#166. To: tom007 (#152)
I'm re-thinking this. Whatever thrust is produced by the engines would be applied to the mass of the plane, seems the wheels and conveyor are immaterial.
#167. To: timetobuildaboat (#153)
e have very few runways higher than 80,000 feet anyway, and only a couple of them are testing conveyor belt technology. The epitomy of madness or sarcasm.
#168. To: All (#167)
#169. To: wakeup, Jhoffa_ (#165)
in a plane, nope
#170. To: Dakmar, tom007, wakeup, markm0722 (#144)
#171. To: Dakmar (#169)
then where are the extra spins of the landing gear wheels going
#172. To: wbales (#170)
The nation is prosperous on the whole, but how much prosperity is there in a hole? - Will Rogers
There are 9,000 hedge funds out there. There aren't that many smart people in the world. - Michael Driscoll, a trader at Bear Stearns & Co. in New York
Some days you just want to pull out the Bonehead Stick and beat people senseless. - mirage
#173. To: markm0722 (#172)
#174. To: Dakmar (#169)
then where are the extra spins of the landing gear wheels going, mister smartguy? Assuming solid construction and a magical fuel supply that plane is stuck on that conveyor belt forever.
The nation is prosperous on the whole, but how much prosperity is there in a hole? - Will Rogers
There are 9,000 hedge funds out there. There aren't that many smart people in the world. - Michael Driscoll, a trader at Bear Stearns & Co. in New York
Some days you just want to pull out the Bonehead Stick and beat people senseless. - mirage
#175. To: markm0722 (#172)
#176. To: Dakmar (#173)
It has nothing to do with thrust or friction since the wheels of the airplane would have to remain motionless in order to satisfy the requirement about the conveyor belt counter rotating in opposite direction...
The nation is prosperous on the whole, but how much prosperity is there in a hole? - Will Rogers
There are 9,000 hedge funds out there. There aren't that many smart people in the world. - Michael Driscoll, a trader at Bear Stearns & Co. in New York
Some days you just want to pull out the Bonehead Stick and beat people senseless. - mirage
#177. To: markm0722 (#174)
As the plane reaches 1 mph relative to the ground
#178. To: markm0722 (#174)
#179. To: wbales (#175)
Bogus. The fan driven skateboard: 1) is moving (gains momentum) before the paper is pulled out from under it; 2) the speed of the paper and the skateboard wheels is not the same and uniform; and, 3) its weight is transferred to the stationary floor under the paper.
The nation is prosperous on the whole, but how much prosperity is there in a hole? - Will Rogers
There are 9,000 hedge funds out there. There aren't that many smart people in the world. - Michael Driscoll, a trader at Bear Stearns & Co. in New York
Some days you just want to pull out the Bonehead Stick and beat people senseless. - mirage
#180. To: markm0722 (#176)
The speed of rotation of the wheels must match the speed of the rotation of the conveyor belt, but that does not imply that speed is in any way related to the speed of the plane down the runway.
#181. To: Dakmar (#177)
As the plane reaches 1 mph relative to the ground
The nation is prosperous on the whole, but how much prosperity is there in a hole? - Will Rogers
There are 9,000 hedge funds out there. There aren't that many smart people in the world. - Michael Driscoll, a trader at Bear Stearns & Co. in New York
Some days you just want to pull out the Bonehead Stick and beat people senseless. - mirage
#182. To: markm0722 (#181)
#183. To: All, SKYDRIFTER (#175)
#184. To: Esso (#183)
"It was an interesting day." - President Bush, recalling 9/11 [White House, 1/5/02]
#185. To: RickyJ (#184)
What does this have to do with this thread?
#186. To: Dakmar (#182)
The wheels could never move from their their original stop position, any movement they make is counteracted by The Belt. That's the rules, man.
The nation is prosperous on the whole, but how much prosperity is there in a hole? - Will Rogers
There are 9,000 hedge funds out there. There aren't that many smart people in the world. - Michael Driscoll, a trader at Bear Stearns & Co. in New York
Some days you just want to pull out the Bonehead Stick and beat people senseless. - mirage
#187. To: Jhoffa_ (#0)
The nation is prosperous on the whole, but how much prosperity is there in a hole? - Will Rogers
There are 9,000 hedge funds out there. There aren't that many smart people in the world. - Michael Driscoll, a trader at Bear Stearns & Co. in New York
Some days you just want to pull out the Bonehead Stick and beat people senseless. - mirage
#188. To: markm0722, Jhoffa_ (#186)
Imagine a plane is sat on the beginning of a massive conveyor belt/travelator type arrangement, as wide and as long as a runway, and intends to take off. The conveyer belt is designed to exactly match the speed of the wheels at any given time, moving in the opposite direction of rotation. There is no wind.
#189. To: markm0722 (#186)
If the wheels are rotating clockwise, then the conveyor belt is rotating counterclockwise. If the outside edge of a wheel is turning at 10 mph, then the outside edge of the conveyor belt is merely turning at 10 mph in the opposite direction
"It was an interesting day." - President Bush, recalling 9/11 [White House, 1/5/02]
#190. To: RickyJ (#189)
If the outside edge of the conveyer belt is turning at 10 MPH, and the plane is moving at 10 MPH then the rotational speed of the wheels would be 20 MPH. But the conveyer belt is suppose to match the rotational speed of the airplane wheels in this fictional situation.
The nation is prosperous on the whole, but how much prosperity is there in a hole? - Will Rogers
There are 9,000 hedge funds out there. There aren't that many smart people in the world. - Michael Driscoll, a trader at Bear Stearns & Co. in New York
Some days you just want to pull out the Bonehead Stick and beat people senseless. - mirage
#191. To: Dakmar (#188)
Does "sat on the beginning of" mean, for our purposes, in a state of rest before we started experimenting on it?
The nation is prosperous on the whole, but how much prosperity is there in a hole? - Will Rogers
There are 9,000 hedge funds out there. There aren't that many smart people in the world. - Michael Driscoll, a trader at Bear Stearns & Co. in New York
Some days you just want to pull out the Bonehead Stick and beat people senseless. - mirage
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