Plane on a treadmill...

[Howard]

It's not powered by the wheels, so it doesn't matter how fast they spin. It will take off. Different story completely if you put a car on a treadmill.

[bsodmike]

An alternative analogy would be a guy on rollerblades, with a rocket strapped on his back, on a treadmill moving in the reverse direction based on the speed of his 'wheels'. Again, since the acceleration isn't due to the rollerblades/his inertia he will move forwards as the thrust exerts a net force (on the air) and his wheels will rotate twice as fast as they would if he was on stationary surface but of course there will be losses due to friction etc which will be minimal to the point of negligible if the 'force' of the rocket is extremely high as it is with an aircraft.

[Steve B]

i completely see where i've been going wrong now.

when considering the wheels in either scenario, i've always assumed them to be frictionfull, like in a car, where all the force is directed into the ground, but having the wheels free to spin causes the plane to seemingly be on a sheet of ice, like a hovercraft isn't bound by the movement of the sea, the air cushion is there to decrease frictional losses.

i geddit

[hsncool]

the people who are saying it will take off are saying it will, because the thrust from the engine are what makes it take off.

bt that isnt true, the engines push the plane forward by taking in air from the front, and blasting it out the back.

***TO ALL THE PEOPLE THAT SAY IT WONT***
im guessing you think it wont because u think the plane is going forwards, and the treadmill goin backwards....so, all in all, the plane is stationary.....but that isnt true. its not a car...the plane is pushed forwads relative to the air with the engines......the wheels allow it to move instead of scraping against the earth.

if the plane was "moving" forwards, and the treadmill backwards, at 1000mph....and counteracting eachother so the plane was stationary...........when the engines came on, they would move the plane forward with the air! so it would still go forwards!!...leve the treadmill and flyy highh!

so there!

this thread has far too many long posts to read all of, (so if some1 quotes me or says something thats directed at me....pm me telling me that u have with a link please or i wont end up ever seeing it)

[JPreston]

http://www.geekculture.com/joyoftech...hives/903.html

HTH

[Steve B]

that was classic

[bsodmike]

haha awesome

What's shocking is that 34% have got it wrong, but expected as the question is meant to be misleading - i.e. you tend to naturally focus on the wheels <-> belt interaction and forget/ignore the engines as a source of thrust and flow of air over the wings to generate lift.

[Howard]

i completely see where i've been going wrong now.

when considering the wheels in either scenario, i've always assumed them to be frictionfull, like in a car, where all the force is directed into the ground, but having the wheels free to spin causes the plane to seemingly be on a sheet of ice, like a hovercraft isn't bound by the movement of the sea, the air cushion is there to decrease frictional losses.

i geddit

[Steve B]

[Nick]

There is a god!

By the way, Steve, just so you know, I used the hovercraft, sheets of ice and water ALL as examples in trying to explain this to you...

[autopilot]

....Now, if someone could point out where im going wrong, then i'd be happy to re-organise my theory; but thats all it is, just a theory...

Here;

its movement is governed by the rotation of its wheels....

[autopilot]

i completely see where i've been going wrong now.

...

i geddit

I have not enjoyed a thread as much as this one for a long time. People keep joining, but not reading the whole thread. Read the whole thread, some examples have been done over and over.

I am loving the way people spend ages trying to prove why it wont take off, then get there eureka moment.

NEXT!

[Steve B]

There is a god!

By the way, Steve, just so you know, I used the hovercraft, sheets of ice and water ALL as examples in trying to explain this to you...

i know mate but the point of realisation came from when i thought about the wheels some more.

you were instrumental

[Taz]

The treadmill will take-off!

[chuckskull]

The treadmill will take-off!

Nah the planes will lose weight

[autopilot]

One of the key things in this riddle, why many get it wrong, is the line "The conveyer belt is designed to exactly match the speed of the wheels, moving in the opposite direction."

Which of course is very misleading, because it's actually the wheels that match the speed of the treadmill, not the other way around.