Something to ponder... and I don't know the right answer

[Belgian rofls]

The plane isn't moving, so it will never be able to take off.

Think about if you're on a treadmill, the faster it goes, the faster you run, but if you jump in the air,
you're not going forward, you'll just go up and then down in the same place (and probably get seriously injured)

                                    '_'

[WolbEm]

the treadmill example doesnt compare becuase your feet are the only source of propulsion. 

Imagine this... belgian in a giant slingshot, wearing rollerskates on said magical conveyor....  what do you think (hope) will happen?

[Kaneda]

Finally someone else agrees w/ me other than the physics doctor/ NYC lawyer.... Drop kick, get me in TE just for being smart.... and i'm only 18












did i mention i'm about to experience time travel?

[Cole]

the treadmill example doesnt compare becuase your feet are the only source of propulsion.

Imagine this... belgian in a giant slingshot, wearing rollerskates on said magical conveyor.... what do you think (hope) will happen?

i was waiting for someone to use this example.  Drop.  nothing will happen because the conveyor has to ove fast enough to counter all motion caused by the slingshot.  It's part of the assumptions in the beginning of the problem. 

[Cole]

Kaneda -A+

Cole, I expected so much more out of you man.  Put down the bong.  Your physics professor want to see you.  He said something about tearing up your diploma.

Riddle me this batman - how do rockets/thrusters work in space if there is no ground to transfer energy to???

Rockets, jet engines and cole all work off the same principle... expanding hot gas. For every action,  there is an equal and opposite reaction.  The expanding hot gas from the jet engines will THRUST the plane  (Thrust - v. to push or drive with force) relative to the rest of the earth and atmosphere (which is not moving with the conveyor). This force will greatly exceed any drag imposed by the conveyor and wheels.  Therefore, the plane will move forward, accelerate, and when it reaches sufficient speed, be able to take off.

Put a jet engine on a car -does it fly? no.  Does it move? yes.

2 things.  the car moves.  move the ground in the opposite direction.  where is the car.  the plane is the same, but with a different name.

second.  we all know how a rocket works, but it is irrelevant.  Jets don't work off hot gas.  They compress air, creating a pressure difference front to back.  It is only heated from engine exhaust and is negl. in the overall.  you could also look at the compression as a rapid increase in air velocity pushing the engine.  The same "two schools" of though in the wing apply here too.

FUCKING ROLLING FRICTION IS NOT A LOT OF DRAG.  and i never said it was .olol.

It does not matter what the source of propulsion is.  The problem is set up to trick you.  All that matters is motion.  Now, stop calling me retarded.  Submit a formal proof.  Maybe I'll do one too. 

[Kaneda]

Lol i was never calling you retarded cole ...but wow, I still dk which one to believe

[Privateer]

We need more threads like this


there are two great things in life... jocks fighting jocks and geeks fighting geeks


and let me tell you, you guys don't play varsity football


Now if you want a response from a business person (ahem myself) I know nothing about all the following information and theories and what not, but I do know how to read and justify reasonable doubt.  Dropkick's theory (or that weird dude) seems to be the right answer after carefully reading both arguements (and after laughing for like 30 minutes of that picture kaneda put up!)


Sorry, its just how it is.... i always pick winners, im like fucking vegas over here

[WolbEm]

Cole, I didnt call you retarded, but i am saying you are still wrong.    Speed and movement are relative.  The problems states that the conveyor will match the speed of the plane in the opposite direction.  If the plane is not moving, then neither is the conveyor.   If the plane were flying through the air, and so was the conveyor, then they would not be moving relative to eachother, but to the rest of the world they are.   Back on the ground, To keep the plane from moving, there would need to be an equal force in the opposite direction of the thrust of the jet engines. The only force the conveyor can exert on the plane itself is friction. Lets just say the plane was moving at 500 mph, so the conveyor is going 500 mph in the opposite direction, that would be 1000 mph net wheel speed.  I dont think that the friction is sufficient to balance the thousands of pounds of thrust generated by the engine.  Do your force vectors. then think about writing a proof.

Get your treadmill and crank it all the way. Then get a toy car. hold the toy car on the treadmill. can you push the toy car along the treadmill?  I knew you could.. heres a cookie.

To say that a jet engine works off of hot gas is a simplificaton.  To say that it works off compression is incomplete.   Let me explain.  A jet engine, is an internal combustion engine similar in operational theiory to your cars engine. all internal combustion engines are essentially air pumps. They mix air and fuel, compress the mix, ignite the mix, and the power is derived from the expanding gas of the combustion - not the compression.  

[WolbEm]

your right Priv.. I dont play varsity football.  But I think I know someone who should 

[Belgian rofls]

the treadmill example doesnt compare becuase your feet are the only source of propulsion. 

Imagine this... belgian in a giant slingshot, wearing rollerskates on said magical conveyor....  what do you think (hope) will happen?

I would hope for cookies...

                          '_'

[Cole]

Get your treadmill and crank it all the way. Then get a toy car. hold the toy car on the treadmill. can you push the toy car along the treadmill?  I knew you could.. heres a cookie.

A plane (747 passenger jet) is sitting on a runway that can move (some sort of band conveyor). The plane moves in one direction, while the conveyor moves in the opposite direction. This conveyor has a control system that tracks the plane's speed and tunes the speed of the conveyor to be exactly the same (but in the opposite direction).

Now, if you push the car, it's velocity is greater than the velocity (in the opposite direction) of the conveyor.  Thus that is not valid.  It is a different problem.  You are confusing the issue of inertial observation verses non-inertial observation.  To the inertial observer, the plan will appear to be stationary.  to someonestanding on the tarmac, the (non-inertial observer), the plane is moving very fast.

The issue is that the plane is not catching any wind, so it will not fly.  A plane needs the movement of air.  It needs a certain amount of air molecules to bombard the leading edge of the wing.  Those air molecules move faster over the top of the wing, slower under, creating a pressure difference. 

Remember that the speed of the wheels will be directly proportional to the radius of said wheels.  The rolling friction is so negligable that for all intents and purposes you can ignore it.  But it could be calculated if you wanted to but you'd need to know more about the bearing system -either way you'd be making assumptions without direct empirical data.

[Cole]

DOLPHINS BE SO SMART

[WolbEm]

Now you are just spouting bullshit. Stop focusing on the wheels and velocity,  becuase they dont move the plane. The intertial frame would be what the outside non-inertial observer sees, not the observer itself. So the frame would include the plane, the conveyor and the ground.  An intertial observer would be inside the plane, where yes, the seats and what not are not moving relative to him.  Newtons laws always will and  apply, because they are... laws.  1st law -body in motion or at rest will remain that way unless there is an outside force acting upon it..in this case the outside force is the thrust of the engines or hand pushing the toy car.  Other forces at work are gravity, the normal force, and drag from the planes wheels on teh conveyor, and drag from the surrounding air. Since these forces will not cancel eachother out, there is a net positive force acting on the plane. 2ND  law - F=M*a  we know we have a net force, and the planes mass is constant, therefore, a > 0. 

[Kaneda]

I still think this all could be simplified into : the plane will move forward because of the action/reaction of the engine, regardless of the wheels spinning twice as fast due to the runway.

[NightTrain]

Cole, you are one of my favorite TE members by far...but I must tell you...the plane will take off.  Drop is right.  It will move down the runway (relative to the earth) at the same rate (minus friction losses associated with the wheels) just as if it were on pavement.  The jets are moving the plane relative to the earth independent of the wheels.

Kaneda, that pictue made me laugh out loud.  Funniest shit I've seen in a while.  I don't care that you are under 21, you are gonna get sponsored for this clan on that picture alone.   

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