A harmless little riddle

Agreed. It is a very good riddle. I got thrown off at the start, but now it's easy to see that the plane will fly.

I reckon the only way to convince these people the plane will fly is to get someone like Bill Eamick in here- maybe he can explain it better.

I am at work at an airport right now. I asked a group of 5 pilots(one of which is a flight instructor).Every last one of them agreed IT WILL fly. As mentioned before and reiterated by the pilots, the plane is traveling through the medium of air. The air is pulled by the prop/jet and in turn the plane is pushed. The wheels are not pushing the plane. Do any of you have alot of time, I would like to see the diference in the amount fo individuals who said it will to those who dont(taking out multiple yes and No's from posters) Anyone up to the challange? We could use the data to see what the "the world is flat" to "the world is round" thinkers on this message board.

Don't let this thread die, I love it!

we do not get to make that decision it is made by the same person who makes all decisions in regards to things living and dying. Chuck Norris. If he wants the thread to die there is nothing we can do to stop it from happening, but if he wants it to live then it will flourish.

A variant on the original riddle:

Can a jet aeroplane land on a moving treadmill?

Assume that the treadmill is the same length as the runway; it is travelling in the opposite direction to the aircraft and the speed of the treadmill always equals the speed of the plane.

If the plane can land then how far along the treadmill would it travel before it comes to a stop?

If the treadmill is moving at the same speed the plane is moving (zero mph, the plane is not moving), the plane will not take off.

the riddler wrote:

An airplane is sitting on an enormous treadmill. As the plane starts its engines, the treadmill runs in the opposite direction at the same speed the plane is moving. Can the plane take off?

xbcha1 wrote:

"Basically, for the frictional force between the treadmill and the plane's wheels to equal the force generated by the plane's thrusters, the treadmill will have to be moving many times faster then the plane."

The 2 quotes contradict each other... Since the originator of this riddle can make the rules, as long as they are logical... THE PLANE DOES NOT MOVE FORWARD AND THEREFORE CANNOT GENERATE THE NECESSARY "PRESSURE GRADIANT" BETWEEN THE AIR ABOVE THE WINGS AND BELOW, TO ACHIEVE "LIFTOFF"....

Concerned wrote:

If the treadmill is moving at the same speed the plane is moving (zero mph, the plane is not moving), the plane will not take off.

My variant was:- Can a plane land on a treadmill?

No mention of take-off in my posting.

jrm wrote:

I'm not entirely sure how planes work but don't they push off of the air? That means that all the treadmill would do is make the wheels spin twice as fast. That would be impractical and pointless and so would not be used on aircraft carriers. Never the less, the plane should be able to take off despite being on a treadmill.

Sigh........

No wonder people think Americans are stupid. Don't any of you pay attention in physics class?

Before the flames begin:

I'm American. I think many Americans are stupid.

Concerned wrote:

If the treadmill is moving at the same speed the plane is moving (zero mph, the plane is not moving), the plane will not take off.

All right, I resisted replying to this inane thread until now, but I can't hold back any longer. This is the simplest, most succinct and accurate post I have seen.

How does everyone else take a simple question and go running off (pun intended) on a long-winded discussion of force vs. speed, the effects of friction, on and on? I suspect the surprising longevity of this thread is largely troll-driven. It pains me to know that my post pushes it back up to the top of the board.

The plane DOES move forward- the contact force between the treadmill and the wheels is not sufficiently high to create enough friction to overcome the thrust from the plane\'s engines. If you sat the plane on the treadmill (no engines) and fired up the treadmill so that it was moving quite fast, the plane would not move back with the treadmill- the wheels would spin and so the plane would only move back some fraction of the distance moved by the treadmill. This is similar to the wheels spinning on your car when you gun it on a wet day- the wheels rotate a greater distance then the car moves.

Fire up the plane\'s engines and the thrust generated massively overpowers the relatively small force acting in the opposite direction (due to friction). The plane is therefore able to accelerate and move forward despite the fact that the treadmill is moving in the opposite direction at the same speed. With just a little more power then what is usually required, the plane takes off.

Can I just make a little point?

Don't you think that if it was possible for a place to take off from one place, they would have made it already? Would save a lot of money on building runways if they could just build one big treadmill for airports?

As a result,

no, the place cannot take off.

From the economics standpoint.

No, the plane doesn't stay still on the treadmill, it moves forward and takes off just like a runway, only on a superlong treadmill. Of course it's entirely useless, but the plane still takes off.

Holy shit when will the pain end?! So many yes and nos... WTF is the right answer?!

All right, I resisted replying to this inane thread until now, but I can't hold back any longer.

What a shame. You were so very close to not revealing how stupid you are!

Aircraft lift is obtained by the airflow over the top of the wing being slower than that underneath(without being too technical).This creates a low pressure area over the wing and hence lift.

In the above scenario there is No airflow because the Aircraft is standing still relative to the ground.

The aircraft is going No where.

For the same reason:If you run a car,at speed, on a Dynomometer then stick your head out the window your hat will not blow off.

There is no airspeed.

Strike that-reverse it. Air travels faster over the wing decreasing the static pressure on top and contributing to lift. (see Bernoulli)

You are assuming that the airplane is not moving.

You are wrong.

You are assuming an airplane propels itself using its wheels, like a car.

You are wrong.

Yes you are correct. The air does travel faster(rather than slower) over the wing to create lift.

But there is still no airflow in this scenario.