| dj-mdx2 |
:21: :7: :banghead:
Don't forget synthetic versus dino and regular versus premium. |
|
|
| mdx99 |
For those who keep on insulting other members or juniors based on
unproved argurments or hyphothetical myths, please keep it somewhere else.
Life is short, don't be too serious! :bootyshak |
|
|
| jhue |
Sorry gmc74, but OceanMDX has nailed the explanation, and is correct.
The key is to understand that the treadmill cannot keep the plane stationary. Regardless of how fast the treadmill runs, the plane will accelerate to the speed where the wings will generate enough lift for the plane to take off. If you cannot get past believing that the treadmill can keep the plane stationary, then you'll never understand the solution.
It took me two reads of the article on the "Straight Dope" to understand what they were saying, and I have some college physics under my belt, as well as an engineering degree from a top-20 school. I will admit - my first response was that the plane cannot take off as there is never any air passing over the wings to generate lift, and I realize now that that was wrong. |
|
|
| oceanMDX |
quote:
Originally posted by gmc74
My reading comprehension??? I am not the one that has chosen, over and over again, to ignore the part of the question (or dismiss it) that states that the treadmill will match the speed of the wheels.
Since this is the case, the plane won't ever go anywhere.
Stating that the treadmill can't possibly go fast enough is absurd in this situation. It is hypothetical, what could you possibly base this on? Other runway sized treadmills you have seen in the past? Come on, the straws that you are grasping at are getting pretty scarce.
The opposite argument to yours is that the wheels could not hold up if they were to spin at a rate twice as fast as the treadmill, and they would tear apart.
Yes your reading comprehension... for the umpteenth time, nowhere does the question say that the treadmill will match the speed of the wheels!!!!!:eek: |
|
|
| oceanMDX |
quote:
Originally posted by Dog
I have a new brain teaser for you guys.
What is the most hypothetically trivial brain teaser that you can create that will get otherwise rational adults to go ballistic over whether they have the right answer to a hypothetical trivial brain teaser?
In order to answer the question correctly, it must inflame passions greater than any past MDX discussion on the iPod Musiclink, the 2001 transmission, Zaino, or why dealers generally suck.
Hint: Try to word the question ambiguously so that it can be misinterpreted in multiple ways.
Prize for correct answer: The inalienable right to insult other forum members' intelligence, reading ability, genetic makeup, and the color of their MDX.:blahblah:
The all time best brain teaser ever presented on this forum goes back to early 2003. That was about whether or not a war between the US and Iraq would be worth it. Only two people involved in the discussion turned out to be right.... that was me and one other forumer....
On another discussion board a university professor presented a numerical series that he claimed was so difficult that no one he ever presented it to managed to solve it. I was not only able to solve his series, but I showed him that one number in his series was wrong.
Here is that puzzle:
Series:
16 17 18 22 24 31 100 ? ?
fill in the next two numbers. |
|
|
| jhue |
quote:
Originally posted by oceanMDX
Here is that puzzle:
Series:
16 17 18 22 24 31 100 ? ?
fill in the next two numbers.
18 is wrong, and IMHO makes it impossible to solve. It should be 20. |
|
|
| oceanMDX |
quote:
Originally posted by jhue
18 is wrong, and IMHO makes it impossible to solve. It should be 20.
It's not impossible to solve because I solved it, and no one warned me that one of the numbers was wrong .... btw, you are right about 18 being the wrong number, it should have been 20... so that was the mistake I also pointed out. Okay, so what are the next two numbers in the corrected series? |
|
|
| hondacuraworld |
| I done a baaaad thing :D |
|
|
| jhue |
quote:
Originally posted by oceanMDX
Okay, so what are the next two numbers in the corrected series?
121 and 1000. |
|
|
| dj-mdx2 |
quote:
Originally posted by hondacuraworld
I done a baaaad thing :D
:bonk: :1pat: :whip: :behead: :banghead: :yodaddy: :xnuts: |
|
|
| gmc74 |
quote:
Originally posted by G. COLTON
Child, you obviously have no reading comprehension ability nor any physics knowledge. Now quit argueing with your elders and go play with your peers, if there are any that will tolerate you.
Enough said.
Goodby!
G
Ahh, I love the "smart" ones that take it down to the level of trying to belittle others.
I also enjoy the irony of essentially telling me I am stupid while misspelling words.
Good Job! |
|
|
| gmc74 |
quote:
Originally posted by jhue
Sorry gmc74, but OceanMDX has nailed the explanation, and is correct.
The key is to understand that the treadmill cannot keep the plane stationary. Regardless of how fast the treadmill runs, the plane will accelerate to the speed where the wings will generate enough lift for the plane to take off. If you cannot get past believing that the treadmill can keep the plane stationary, then you'll never understand the solution.
It took me two reads of the article on the "Straight Dope" to understand what they were saying, and I have some college physics under my belt, as well as an engineering degree from a top-20 school. I will admit - my first response was that the plane cannot take off as there is never any air passing over the wings to generate lift, and I realize now that that was wrong.
I haven't been to straight dope, but are you certain that the question posed their was the same?
One major difference, which I have seen on other sites, is that this question here states that the treadmill will match the speed of the wheels, other sites say that it will match the speed of the plane.
If the question were worded this way, his answer would be correct, but the question presented here is not the same, it states that the treadmill will move at the same speed as the wheels, which is very different. |
|
|
| mdx99 |
quote:
Originally posted by gmc74
Ahh, I love the "smart" ones that take it down to the level of trying to belittle others.
I also enjoy the irony of essentially telling me I am stupid while misspelling words.
Good Job!
That's a good one, HA HA:2: |
|
|
| oceanMDX |
quote:
Originally posted by jhue
121 and 1000.
You're close, double check the numbers please. |
|
|
| JL_SS |
quote:
Originally posted by oceanMDX
You're close, double check the numbers please.
jhue's 1,000 should be 10,000. |
|
|
| oceanMDX |
quote:
Originally posted by JL_SS
jhue's 1,000 should be 10,000.
Yes! |
|
|
| oceanMDX |
quote:
Originally posted by gmc74
If the question were worded this way, his answer would be correct, but the question presented here is not the same, it states that the treadmill will move at the same speed as the wheels, which is very different.
The question isn't worded the way you purport.
At any rate in physics, natural rules - not semantics. :4: |
|
|
| gmc74 |
| I still don't see it, we will have to agree to disagree until it is proven one direction or another. |
|
|
| jhue |
quote:
Originally posted by gmc74
I still don't see it, we will have to agree to disagree until it is proven one direction or another.
[delayed response due to being on vacation for five weeks]
Maybe this will help: imagine a plane is flying through the air at 200 knots. You fly a conveyor belt up to the plane and adjust the speed of the moving belt so that its speed matches the plane. You then bring the conveyor belt into contact with the plane's wheels. What happens?
Nothing - the wheels on the plane are spun forwards by the moving belt, but it doesn't affect the speed of the plane (ignoring friction for the moment). It doesn't matter how fast the belt is moving. It could be moving at 1000mph backwards - spinning the planes wheels with the belt doesn't affect the plane's speed. It's the same idea when the plane is taking off. The conveyor belt can spin the plane's wheels but it can't slow down the plane (again ignoring friction, but that's small compared to the forward thrust generated by the planes engine).
Or think about a car on a rollers like a dynomometer, except with freely spinning frictionless rollers, vs a plane mounted on the same frictionless rollers. The car can't go anywhere - it just spins the rollers. But the plane can pull itself off the rollers. Similar idea to the conveyor belt. |
|
|
| jhue |
quote:
Originally posted by JL_SS
jhue's 1,000 should be 10,000.
As an EE and someone who works with numbers in hex and binary every day, I should be ashamed to have been off by one bit and not realized it. |
|
|
| mdxforever |
I didn't read the 119 replies but I will throw in my 2¢ anyway -
Lift is a function of air speed not ground speed.
If the belt is moving at the same speed as the wheels then the craft is stationary. The wheels would be turning at take off speed but the aircraft isnt moving. No wind speed, no lift.
i.e. 200mph ground speed, 0mph air speed.
{edit}:
actually the clue is in the question itself - "There is no wind". |
|
|
| jhue |
quote:
Originally posted by mdxforever
If the belt is moving at the same speed as the wheels then the craft is stationary. No wind speed, no lift.
Like I wrote before, until you can get past believing that the belt can keep the plane stationary, you will never understand the answer to this puzzle. It took me a while to understand this but I eventually got there.
quote:
actually the clue is in the question itself - "There is no wind".
You're reading something into the question that you're not meant to. The "trick" to this puzzle is to understand that the belt cannot keep the plane stationary. In fact, were it not for the rolling resistance of the tires, and friction of the wheel bearing, the belt should not be able to exert ANY force (other than vertical) on the plane at all. |
|
|
| NewMDXOwner |
| So sad! For once in his life G. Colton is right, but he made such an ass of himself nobody wants to listen :9: |
|
|
|
