Let's just read the question and decide what we're being asked about:

First, the plane "begins to move forward." So, forward motion is possible, although it isn't stated whether this forward motion is relative to the surface of the treadmill, or relative to the ground.

Next, the treadmill is described. It is "made to match the forward speed of the plane, only in the opposite direction." What the forward speed of the plane is relative to remains unspecified. The treadmill is said to "move backwards beneath the aircraft as the aircraft moves forward." What the forward motion of the plane is relative to remains unspecified.

Thus, when the treadmill is said to "match the forward speed" of the plane, it isn't stated how this speed is determined. When the treadmill is said to "move backwards...as the aircraft moves forward" it isn't stated how this motion is determined.

So, for step number one, to read the question and determine the parameters of what is being described, we cannot describe the treadmill because we cannot describe the plane, therefore we certainly cannot describe their relationship.

When Mythbusters tests this scenario, I will be curious to see what is tested. Because the question as stated here isn't something you can test.

My point exactly.

For the record, the plane will not take off!

That is simply my opinion which is worth as much as you paid for it.










but I'm still right :p

The plane will take off.

As Newton said to Edmund Halley, "I have calculated it."

Right. That's what makes it a trick question. The first instinct of someone who knows how wings work is to assume that the spirit of the question is that the plane is held stationary. That assumption is not present in the question. Phage0070's wheel friction interpretation is the most grounded in reality of the ways to follow that line of thought, but even that requires the additional assumption of landing gear that can survive the friction (against the road, and internally on the bearings) required to counter an airplane engine, which would likely be several times the speed of sound.

The "relative to the ground" interpretation can actually be done with a real plane, so I'm guessing that that's the one the Mythbusters will do.

Oh for Christ's sake... IT'LL BE ON IN JUST A FEW HOURS.


Just sit tight and wait, 'kay?

my prediction is that the Mythbusters episode will do naught but inflame the argument into further heretofore unrealized levels of ridiculousness.

.

Go right back to Kitsume's post #1. That means the plane moves forward relative to air - independent and irrelevant to a treadmill.

Between plane and the treadmill are wheels. Wheels spin as slow or fast as necessary so that plane and treadmill remain completely independent of each other. Grasp the major significance of the word independent. Tread mill moving forwards or backwards will only affect how fast and which direction wheels spin. Tread mill will have no affect on the plane.

I am still completely mystified why this is not obvious to everyone. In post 104, Happy Monkey again and accurately answered. He is answering to others who remain confuse in post 196.

Meanwhile, the question was answered in maybe five different ways - all coming to the same conclusion - in post 152. Does not matter what speed or direction (a one dimensional problem) a treadmill moves. It is that simple. Some still have difficulty after 305 posts and 13 months later? I am completely baffled why something so simple has been made so difficult.

It's this simple. Wheels mean the plane is not affected by the treadmill (except by some trivial bearing resistance that is made 100% irrelevant by the planes jet engines). Wheels and jet engine means the treadmill can be replaced by a runway (a treadmill moving as 0 Km/sec) and have the exact same answer.

And not a single comment about Bush, he must be drinking, he is slipping. :D

Wheels on a jet plane even make the Bushes irrelevant to the problem. In 356 days, even we will be independent of the bushes (which is really only a good place to pee).

I knew your obsession would never leave you. Who are you going to talk about when he is gone?

I ran on a treadmill for about 35 minutes the other day, I did not move forward. Does it matter if it's me or a jet plane on the tread mill?

I am totally tailposting here, but.......

Isn't the issue the planes speed relative to the earth? If the plane is spinning on a treadmill, then it isn't moving at all relative to the earth. I must be missing something - lil help?

Yes it does, your forward movement is foot (wheel) driven and the plane's is not.

^NO^

The wheels are irrelevant.

if there were no wheels, the plane would fall off the treadmill you dill.

yeah....the treadmill is unable to cancel the plane's motion because the wheels of the plane negate any and all reverse motion the treadmill can generate.

the wheels are what power the treadmill in reverse - therefore a net movement of.......................
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yup still ZERO.


















cock

the wheels on the plane?

Plane wheels, freewheel. They have no effect on the movement of the plane unless you put the brakes on.

yes - de plane, de plane!

The impetus created by the forward thrust of the plane's engines is negated by an equal and opposite "thrust" of the treadmill. The plane is "treading water."

not if the wheels are free to spin, it isnt.

You know how cyclists can get those rollers that they can use indoors to train on when it's raining?

Well, this treadmill thing is the same concept really in some ways. If planes were able to take off simply by the thrust created by engines from the treadmill, doesn't it stand to reason that airports would create some kind of giant set of rollers so they don't need long runways?

:rollhappy :rollhappy :rollhappy :rollhappy :rollhappy :rollhappy

You were almost right, LJ. The Mythbusters episode didn't cause people to argue more--only people who obviously didn't watch it to continue to rehash arguments from the last eight thousand pages...

Hey classicman: SHUT UP AND WATCH THE GODDAMN EPISODE.

Ali, I'll make a small concession for you since you perhaps can't get the show in Oz. Cyclists--just like cars, just like people's feet on a treadmill--are pushing on the ground to go forward. The plane is not pushing on the ground, with its wheels or anything else. It's pushing on the air with those massively explosive jets it has.

You know where else planes can take off from?

WATER. That shit's just as slippery as a backwards-moving treadmill.

Huh, didn't see the episode..So, the plane took off from the treadmill?

I'd say I hate it when I"m wrong, but it happens so often that I've become used to it.

Yes.

Thanks...Goes back to running on treadmill, and roasting my noodle thinking about all of this.

Maybe this will help: just imagine what would happen if, while running in place on your treadmill, you strapped a jet pack to your back and turned it on.

Well why don't airports have big rollers then instead of making massive runways?

Because the jets would push the plane off the rollers before it had enough airspeed to take off.

Well I don't understand why that would happen if the bearings are loose enough or however you engineer those sorts of things. I guess that's why I'm not an engineer.

Because the treadmill effect is irrelevant to the takeoff. The plane still needs just as much runway, whether it's a treadmill or not. All the rollers would do is make the massive runway more expensive, and prevent planes from using their brakes on it when landing or taxiing.

The treadmill does not stop the plane from moving forward.

If you were standing in a position such that you could see the plane, but not the runway, you wouldn't be able to tell from the plane's movement whether there was a treadmill. It still moves forward the same distance, relative to the air, before lifting off.

Hmmmm...I didn't think about landing.

Thanks for the explanation too HM. I understand now.

Well they never told you that it was a Harrier. So the wheels never move and the treadmill never moves.




http://people.bath.ac.uk/cjc25/year1...s/image019.jpg

Geez - ok. I was wrong! Lighten up Clod.






I still don't get it though.

Do you get how a water plane takes off, classic?

no I'm not a freakin pilot - I don't get the concept at all - I'm just too stupid I guess - kthxbye.

Back in the 80's, Letterman did a stunt in the hallway of NBC studios where he sat in a wheeled office chair and discharged a fire extinguisher. He was doing races down the hall with another guy. This problem reminded me a bit of that.

oh. so what you are saying is that the plane won't take off?

Wait... are we assuming that the treadmill is in a horizontal position?

OK, reading all this makes my brain hurt.

What did Mythbusters say?

Yah. Me too. I was busy assembling my new treadmill from bigbox mart and missed the show. What fun. Not.

The plane took off.

:lol: I bet the plane is going to be even harder to assemble.

Busted. I love how they phrased the question so they could bust it. If the myth had been "the plane can take off" it would have been confirmed.

So, why is there still an argument?[/horrible tailposting]

Wtf? The plane was moving forward...so the treadmill wasn't equal to the plane? Well duh, it's not stationary as the original question seemed to suggest, of course it will take off, it will just take the wheels longer to get up to speed.

:bolt:

It was moving backward relative to the ground at the same speed the plane was moving forward relative to the ground.That was the trick in the trick question- it seems to suggest that the plane will be stationary, but doesn't actually say so.No. The wheels actually move twice as fast.

After viewing that video, I am no longer willing to concede......

I think

Right. "Plane can't take off": Busted. "Plane can take off": Confirmed.

All a little anti-climactic if'n you ask me. All the wasted popcorn. ;)

Right. This is usually a question: "Can a plane on a treadmill take off?"
But since they are the mythbusters they phrased it so they could score a "bust."

Also (separate point here) they phrased the scenario to specify "ground speed."

They ran the treadmill at takeoff velocity (25 mph). I wonder what the result would have been if they ran the treadmill at the plane's maximum velocity.

If enough viewers complain about their testing methods, they will revisit the myth. Sometimes they're wrong. I'd say this one is still wide open!

HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA ha ha ha ha ha ha ha :::groan:::

The same thing. For axle friction to noticeably slow the plane would require a treadmill moving at unimaginable speed. Now that I think of it, a treadmill moving fast enough to slow the plane might even cause enough of a wind-tunnel effect to counteract that friction.

Not quite exactly the same thing, they would need a longer strip of fabric. [/nitpick]