# Our schools have failed us...

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JaxsonRaineposted 5 years ago

A disturbing number of people, probably products of public education, believe that a plane on a treadmill won't be able to take off.

The fact that this debate still goes on just proves that our schools are a continual failure.

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Uh-oh, I'll take a chance on putting my foot in it here... Won't be the first time.

How can a plane on a treadmill take off? There's no air rushing by the wings to provide lift.

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JaxsonRaineposted 5 years agoin reply to this

If you put a car on a treadmill, set the treadmill to 20mph, and the car to 20mph, the car will remain stationary. This is because the car imparts force through the tires, against the ground. So, for the car to say 20mph, the wheels have to be spinning at 20mph, and since the ground is moving at 20mph, then the net movement is 0.

A plane, however, doesn't impart force through the tires. It imparts force on the air, so it's not connected in any way to the treadmill, except through free-spinning wheels. So the plane will move forward, at 20mph relative to the air, where the car will hold still, at 20mph relative to the treadmill.

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Dont Taze Me Broposted 5 years agoin reply to this

Plane and treadmill "debates" are a symptom but the problem with public education can be found here: http://hub.me/aeraM

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Josakposted 5 years agoin reply to this

Because the air is independent of the treadmill so as far as the air is "concerned" the plane is moving just the same as if it was not on a treadmill at all so the air will still rush under the wings.

Frankly however it's a slightly tricky one and even some physics professors replied incorrectly because the answer seems so instinctively correct so it's nothing to be foot in mouth about. It's one of those things people tell each other (and themselves) so they can convince themselves that they are smarter than others, makes them feel quite superior

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JaxsonRaineposted 5 years agoin reply to this

Eh, there's no problem with people giving the wrong answer. The problem is the people who refuse to listen to the explanation.

Usually though, it has to do with the wording of the question. If you say 'the treadmill matches the speed of the wheel', then that's not really possible, because the speed of the wheel will always be the speed of the plane + the speed of the treadmill. That just reinforces the idea that the plane is holding still.

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Josakposted 5 years agoin reply to this

Oh that isn't a problem with our education system that is a problem with human nature, we can't accept that we are wrong and we quickly consider ourselves part of a "team" in a debate and are loath to switch sides.

http://en.wikipedia.org/wiki/Confirmation_bias

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JaxsonRaineposted 5 years agoin reply to this

It's largely a problem of education... we don't teach critical thinking, we don't teach problem solving, we don't teach logic.

We teach tests. That's it.

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Dont Taze Me Broposted 5 years agoin reply to this

More like they teach how to cheat on tests. http://usnews.nbcnews.com/_news/2012/11 … tests?lite Authorities say the scheme affected hundreds — if not thousands — of public school students who ended up being taught by unqualified instructors. http://www.ajc.com/news/news/more-cheat … t-e/nSPqj/

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I decided to work through an extreme example...

Going in reverse at 300 miles an hour (or at whatever speed one wishes). And carrying the plane along with it.

Plane starts engines; initiates full thrust...

Since, as you stated, the plane is independent of the surface it is on; the effects of that thrust will be cumulative until airborne and air resistance starts setting in.

Cumulative wins over constant every time.

You are right.

I leaned something today.

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Mighty Momposted 5 years ago

Bernoulli is rolling over in his grave.

working