A harmless little riddle

the reason planes have to go 150+ mph to take off is so that they get 150+ miles of wind resistance on the wings to be able to lift the plane. the way a plane works is that the top of the wings are arched so that the air goes faster, making the air molecules more thin, then the dense air molecules below the wings push up on the wings which is how a planes gets its lift. On a treadmill the wind resistance would be 0 mph, and their would be no lift. so the answer is no.

It will not, of course, be able to take off. Any entry level physics student/chimp with a learning disability would be able to tell you that.

It really surprises me that so many people think it would be able to take off. Then again, this IS Letsrun . . .

You guys are idiots wrote:

It will not, of course, be able to take off. Any entry level physics student/chimp with a learning disability would be able to tell you that.

It really surprises me that so many people think it would be able to take off. Then again, this IS Letsrun . . .

The point is the treadmill exerts its force on the wheels, not the plane. As the wheels do not transfer this force to the plane, the plane moves forward, accelerates until it reaches however many miles per hour, and takes off. It is unaffected by the treadmill. The wheels will simply be spinning twice as fast as they normally would be when the plane takes off.

Ah, irony.

Whatever his username might be, the plane still isn't taking off. Sorry. The air is not moving over the wings at 150+ miles per hour relative to them. The air is sitting on top of the wings, barely moving at all. Therefore the plane gets no lift. Therefore it does not take off.

I am a fu

[qThe point is the treadmill exerts its force on the wheels, not the plane. As the wheels do not transfer this force to the plane, the plane moves forward, accelerates until it reaches however many miles per hour, and takes off. It is unaffected by the treadmill. The wheels will simply be spinning twice as fast as they normally would be when the plane takes off.

You really ARE moron.

The "point" is that the plane will remain stationary relative to its surroundings (and more importantly, the surrounding AIR), thus producing NO air current, which is ESSENTIAL for takeoff.

guesser wrote:

Whatever his username might be, the plane still isn't taking off. Sorry. The air is not moving over the wings at 150+ miles per hour relative to them. The air is sitting on top of the wings, barely moving at all. Therefore the plane gets no lift. Therefore it does not take off.

Bingo. This guy is NOT an idiot.

At first I thought only the wheels are turning and the plane is sitting in one place, but the reason the wheels spin is because the engines are producing thrust, which would move the airplane forward as it normally would. I think the movement of the treadmill would have little effect except to make the wheels turn faster. Presuming that the treadmill is the length of a normal runway, the plane would gain speed and take off.

I think some of you may be confused by the question.

Since the treadmill will be moving at the same speed as the airplane's wheels, the airplane will not be moving through space. Just as when you run on a treadmill, your legs are cycling, but your body does not actually have any horizontal displacement about the sagittal plane.

Since there is no forward movement, the air surrounding the wings is STATIONARY. The very fundamental source of flight for an airplane is AIR MOVEMENT past (or more accurately, above and below) the wings, which creates the lift.

Therefore, with no air current to cause lift, the plane will remain on the treadmill and be unable to take off.

Haha, this is why it is a riddle; it is meant to be tricky and fool people without any understanding of how an airplane takes off.

If the vehicle in question was a car with wings, then no, it would not fly. It would be motionless.

But it is not a car with wings. It is an airplane with free-spinning wheels which DO NOT EXERT A SIGNIFICANT FORCE ON THE PLANE.

Yeah, but we propel ourselves by using our legs to exert a force on the ground. An airplane propels itself by exerting a force on the atmosphere.

Because in this problem the atmosphere's movement is negligent, and definately not connected to the movement of the treadmill, the plane can do whatever it pleases, including taking off.

the answer is simple. Where are you going to find a treadmill that goes this fast? I have only seen ones that go like 13 miles an hour.

duh!

Ding! Ding! Ding!

Correct- the plane will not be moving fowards, therefore no air will be travelling over the wings and no lift will be created. I don't see how people have problems understanding this.

if you do a google search on "airplane" and "treadmill" you will find that most people answer this riddle as "yes".Not saying I know what is right or wrong, but most people seem to think that it will take off.

guesser wrote:

of course not. a plane develops lift from the air traveling over the wings.

EVERYBODY WHO HAS REPLIED TO THIS THREAD SO FAR IS A MORON!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! NOBODY HAS IT RIGHT.

LISTEN HERE: THE RIDDLE STATED THAT THE TREADMILL MOVES IN THE OPPOSITE DIRECTION AT THE SAME SPEED THAT THE PLANE IS MOVING. OBVIOUSLY SPEED IN THIS SENSE IS RELATIVE TO A NEUTRAL REFERANCE POINT, THE GROUND. THAT MEANS THAT IF THE PLANE IS MOVING AT 150MPH TO THE GROUND THE TREADMILL IS MOVING IN THE OPPOSITE DIRECTION AT 150MPH. WHICH MEANS THAT THE WHEELS ARE MOVING OVER THE TREADMILL AT 300MPH. THE PLANE WILL TAKE OFF.

IF THE PLANE DOESNT TAKE OFF, LIKE MOST OF YOU ANSWERED, THAT MEANS THAT IT IS JUST SITTING THERE ON THE TREADMILL NOT MOVING AT ALL, WHICH MEANS THAT THE TREADMILL IS NOT MOVING AT ALL, WHICH MEANS THAT YOU HAVE A F***ING PLANE WITH ITS ENGINES ROARING AND NOT ONE GOD DAMN THING COMING OF IT. YOU GUYS ARE F***ING BRILLIANT!!

How can it take off? The air travelling over the wings is what creates a vaccum which creates lift. If the plane is not moving fowards*, no air will be travelling over the wings...... hence no lift is created.

*if the treadmill is moving at 150mph, and the plane is moving at 150mph, the speed of the plane relative to EVERYTHING around it, not just air, is 0mph.

Arrogant and wrong. Are you George Bush?

1 air must move relative to the airplane

2 the question was about airplanes not jets.

it would not take off.

[quote]Easy 10 wrote:

An airplane propels itself by exerting a force on the atmosphere.

quote]

it does this ONLY ONCE IT IS FLYING. first it has to TAKE OFF. in order to take off, it has to go fast enough ON THE GROUND to allow the wings to gain lift

assuming the treadmill will keep the plane stationary, it won't leave the ground

Opposite meaning the other way. Please refrain from posting bullshít like that again. It doesn't matter if you post all of your messages in CAPITAL LETTERS, you're still going to be wrong.