How smart are you? Take this poll.

[89coupe]

Saw this on another forum

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 planes speed and tunes the speed of the conveyor to be exactly the same (but in the opposite direction).

The question is:

Will the plane (747 passenger jet) take off or not?

[shakalaka]

It will if its scheduled to take off. lol

EDIT: I thought it was some knda trick question.

[LudeRoca]

well the way i see it is it wont take off due to the fact the wings have a major part in the plane taking off. So if there is no wind the plane cant lift its nose up or take off.

[89coupe]

Originally posted by LudeRoca
well the way i see it is it wont take off due to the fact the wings have a major part in the plane taking off. So if there is no wind the plane cant lift its nose up or take off.

So what is stopping the plane from not moving?

[FatboyTheHungry]

No. Air speed over the wings is what is important. Since the runway's reverse speed matches the planes forward movement on the ground, the wings will be stationary. This equals NO LIFT. the plane goes nowhere.

[Zero102]

The engines would have to put out enough force to keep the plane from moving, however it's air speed would still be 0. Since the wings provide all of the lift, and lift is a function of air speed, the plane will never lift up, or take off.
In actuality, the engines are essentially fighting the friction in the wheel bearings, and that's it.

[89coupe]

How are the wheels stopping the plane from moving forward?

[ecstasy_civic]

what the fuck kind of question is this?
a conveyor on the runway?:rofl:

[89coupe]

Originally posted by ecstasy_civic
what the fuck kind of question is this?
a conveyor on the runway?:rofl:

Hypothetical question to mess with your head.

[djayz]

if the plane could take off dont you think they wouldve put converyors onto runways or wouldve mastered the art of vertical lift off by now?

[Weapon_R]

Yes it can fly. If the plane released its brakes, the wheels should spin to counteract the conveyor belts movement. The plane would remain stationary until the engines were turned on, counteracting any friction that the wheels have on the belt, and it would fly. I think...

[gpomp]

no airflow = no lift = no flight, unless you got some mach 5 winds blowing towards the plane....

[szw]

IMO yes it will take off. I don't think the conveyer belt has any affect at all on the planes movement.

[Raz2]

Uhm, planes are driven by jets/propellors, NOT their wheels, what the ground is doing beneath makes no difference to the plane, of course it will take off.

- Rasmus

[RX-7_TWINTURBO]

yes it will take off

[LudeRoca]

Originally posted by szw
IMO yes it will take off. I don't think the conveyer belt has any affect at all on the planes movement.

dude... planes dont take off without wind blowing towards the plane. Notice the flaps on the wings when the plane is taking off or landing. Those control the movement and aerodynamics of a plane. When taking off the flap are up. This helps the plain to get its nose in the air. how would this happen if the plain isnt physiclally moving?

[Ekliptix]

Problem solved:

http://www.dbmueller.com/military/images/harrier.jpg

[szw]

Originally posted by LudeRoca


dude... planes dont take off without wind blowing towards the plane. Notice the flaps on the wings when the plane is taking off or landing. Those control the movement and aerodynamics of a plane. When taking off the flap are up. This helps the plain to get its nose in the air. how would this happen if the plain isnt physiclally moving?

I've bolded the part that I disagree with. I don't think the conveyer belt will alter the movement of the plane at all.

[89coupe]

LOL...its pretty funny how split the vote is.

Here is something that may help you wrap your head around the question.

If you were running on a treadmill and I came up behind you and shoved you, what would happen?

[Weapon_R]

Originally posted by LudeRoca


dude... planes dont take off without wind blowing towards the plane. Notice the flaps on the wings when the plane is taking off or landing. Those control the movement and aerodynamics of a plane. When taking off the flap are up. This helps the plain to get its nose in the air. how would this happen if the plain isnt physiclally moving?

Think hovercraft. A hovercraft still moves forward because the thrust provided by the propellor is greater than the friction of the water.

Think of a hovercraft idling in water. If the propellor provides just enough power to keep it in one place during a current (the airplane on a conveyor) and then you floor it, the hovercraft moves.

[gpomp]

Originally posted by 89coupe
If you were running on a treadmill and I came up behind you and shoved you, what would happen?
the treadmill probably doesnt have a feedback control system that monitors my speed.

[JayWang]

Originally posted by Weapon_R
Yes it can fly. If the plane released its brakes, the wheels should spin to counteract the conveyor belts movement. The plane would remain stationary until the engines were turned on, counteracting any friction that the wheels have on the belt, and it would fly. I think...


WRONG.

read the questios again.

the conveyer belt has a CONTROL SYSTEM.

it can monitor the speed of the airplane wheels and responds by rotating the conveyer belt in the opposite direction, essentially making the plane have a velocity of zero.

assuming that the control system is ideal, then it will PERFECTLY and INSTANTLY counteract the RPM of the wheels. as a result, the plane has a velocity of zero.

ie if the wheels are spining at 60 RPM or whatever, then teh belt will be going at X RPM in the opposite direction.
(whatever RPM that will make the plane stay on the spot)

the belt RPM adjusts with the wheel RPM, no the other way around.

so unless you have a busted ass control system, or the plane turns into a helicopter, this 747 ain't going no where.

kinda like the calgary flames.

GO LEAFS GO

[szw]

If you were driving a car on this conveyer belt, you would be staying still. But a plane's wheels are not driven, the jets are what drives the plane. Due to the conveyer belt, the wheels will be spinning at twice the speed they normally would, but the plane would be moving normally.

This assumes a frictionless surface, and that the wheels don't burn up and melt.

[Zephyr]

So what is the answer?

[gpomp]

Originally posted by szw
If you were driving a car on this conveyer belt, you would be staying still. But a plane's wheels are not driven, the jets are what drives the plane. Due to the conveyer belt, the wheels will be spinning at twice the speed they normally would, but the plane would be moving normally.

This assumes a frictionless surface, and that the wheels don't burn up and melt.
well, since it's a perfect control system.. the conveyor would move as fast as it needs to in order to stop the plane from moving, no?

[89coupe]

Originally posted by JayWang



WRONG.

read the questios again.

the conveyer belt has a CONTROL SYSTEM.

it can monitor the speed of the airplane wheels and responds by rotating the conveyer belt in the opposite direction, essentially making the plane have a velocity of zero.

assuming that the control system is ideal, then it will always counteract the RPM of the wheels.

ie if the wheels are spining at 60 RPM or whatever, then teh belt will be going at X RPM in the opposite direction.
(whatever RPM that will make the plane stay on the spot)

the belt RPM adjusts with the wheel RPM, no the other way around.

so unless you have a busted ass control system, or the plane turns into a helicopter, this 747 ain't going no where.

kinda like the calgary flames.

GO LEAFS GO

What do the wheels have to do with stopping the plane from moving forward?

[Raz2]

ABSOLUTELY NOTHING! :) (people are stupid)

- Rasmus

[Weapon_R]

Originally posted by JayWang



WRONG.

read the questios again.

the conveyer belt has a CONTROL SYSTEM.

it can monitor the speed of the airplane wheels and responds by rotating the conveyer belt in the opposite direction, essentially making the plane have a velocity of zero.

assuming that the control system is ideal, then it will always counteract the RPM of the wheels.

ie if the wheels are spining at 60 RPM or whatever, then teh belt will be going at X RPM in the opposite direction.
(whatever RPM that will make the plane stay on the spot)

the belt RPM adjusts with the wheel RPM, no the other way around.

so unless you have a busted ass control system, or the plane turns into a helicopter, this 747 ain't going no where.

kinda like the calgary flames.

GO LEAFS GO

Sorry, Wang, but you are wrong. An airplane's wheels are not driven. The wheels would spin faster than they normally would, but the airplane would still take off.

[?????]

Yes it can take off.

The plane doesn't gain speed to take off using its wheels. Its pushed by the jet engines.

[Raz2]

I think we should put Mr wang on a tread mill, and push him.

- Rasmus

[Ekliptix]

Originally posted by Zephyr
So what is the answer?

Vtec engages and there's a shitstorm of takeoffs.

[szw]

Originally posted by gpomp

well, since it's a perfect control system.. the conveyor would move as fast as it needs to in order to stop the plane from moving, no?

Yeah thats not what I am saying though. I think that no matter what the speed of the conveyer belt is, it won't affect the forward motion of the plane. I'm having trouble putting what I'm thinking into exact words though.

[LudeRoca]

you guys dont get it. The plane moves with thrust from the engine. THe engine could be goin at full blast but unless there is wind comming in the opposite direction it aint gonna take off. Yes this may pushh the plane forward. but planes take off on air speed. No air speed. NO lift off. its as simple as that.

if that doesnt make sense to you try to think of how the planes nose lifts up before taking off.

[szw]

Originally posted by LudeRoca
you guys dont get it. The plane moves with thrust from the engine. THe engine could be goin at full blast shooting out a lot of thrust. Yes this may pushh the plane forward. but planes take off on air speed. No air speed. NO lift off. its as simple as that.

You are making the assumtion that the conveyer belt causes the plane to stay stationary (with reference to someone say standing across the field watching it).

I am saying that the conveyer belt DOES NOT keep the plane stationary.

[Raz2]

Uhm...

No?

Unless you put the brakes on those wheels... you're wrong :)

- Rasmus

[89coupe]

Originally posted by LudeRoca
you guys dont get it. The plane moves with thrust from the engine. THe engine could be goin at full blast shooting out a lot of thrust. Yes this may pushh the plane forward. but planes take off on air speed. No air speed. NO lift off. its as simple as that.

if that doesnt make sense to you try to think of how the planes nose lifts up before taking off.

LOL...so why do you think there will be no air speed? The air isn't effected by the conveyor belt.

[JordanEG6]

Originally posted by Ekliptix


Vtec engages and there's a shitstorm of takeoffs.

bahahahaha


simple physics, its not going to take off, the plane remains stationary therefor, no wind flow or resistence to cause lift. it will say in one spot. its like running a on a treadmill.

[89coupe]

Originally posted by JordanEG6


bahahahaha


simple physics, its not going to take off, the plane remains stationary therefor, no wind flow or resistence to cause lift. it will say in one spot. its like running a on a treadmill.

See my question above.

Why do you think there will be no air flow?

[Zephyr]

Originally posted by Ekliptix


Vtec engages and there's a shitstorm of takeoffs.

Oh ok, makes sense.

I'm guessing it won't take off because it's just sitting there.

[Raz2]

Fuck

people who are wrong and argue to the death that they are right smell like cheese... moldy cheese.

[LudeRoca]

because the plain isnt moving. There is air goin thru the engines but there isnt any goin over the wings.

[gpomp]

Originally posted by LudeRoca
because the plain isnt moving. There is air goin thru the engines but there isnt any goin over the wings.
it never said that the plane was stationary. you can't assume that

[Zephyr]

Originally posted by gpomp

it never said that the plane was stationary. you can't assume that

well it says it's just "sitting" there so it's not even moving.

[89coupe]

Originally posted by LudeRoca
because the plain isnt moving. There is air goin thru the engines but there isnt any goin over the wings.

So you don't think the jet engines will push the plane forward?

[Raz2]

Are we still even discussing this? :eek: :eek: :eek:

ok guys.. do this: take a hovertoy RC thingie from "TheSoureCC" and put it on mom and dads treadmill... then turn the treadmill on WARP SPEED... and turn the hovertoy on.. notice it stays stationary? Now, wheels have a similar effect, albeit not entirely frictionless they do have a tendency to roll in the opposite direction that the ground underneath them is rolling.

:banghead: <-- see if that helps.

[Zephyr]

so what's the answer.

[Ekliptix]

Originally posted by JordanEG6


bahahahaha


simple physics, its not going to take off, the plane remains stationary therefor, no wind flow or resistence to cause lift. it will say in one spot. its like running a on a treadmill.

what's keeping the jets that are pushing against the air to allow the plane to move forward?

[JordanEG6]

Originally posted by 89coupe


See my question above.

Why do you think there will be no air flow?

because if the planes velocity is equal to that of the conveyor, then it really isnt going anywhere. if you run across a football feild theres air resistance because your moving against free wind, if you run on a treadmill, there will be none.

[szw]

Originally posted by Zephyr


well it says it's just &quot;sitting&quot; there so it's not even moving.

No it doesn't say that.


Also I think there is some confusion about what is being asked.

I think everyone agrees that if the plane moves forward in relation to someone standing outside the plane, it will take off. If the plane remains stationary from the viewpoint of that same person, then the plane will not take off.

The question being asked is: Does the conveyer belt keep the plane stationary?

My stance is that the plane WILL move forward regardless of the treadmill. but i'm still trying to think of a good explaination of why I think this

[JordanEG6]

Originally posted by Ekliptix


what's keeping the jets that are pushing against the air to allow the plane to move forward?

well, like the riddle/problem states if in anycase the jets cause the plane to move forward (increase in speed), the conveyor will match it and still remain stationary, wont it?

[Ekliptix]

Originally posted by JordanEG6


because if the planes velocity is equal to that of the conveyor, then it really isnt going anywhere. if you run across a football feild theres air resistance because your moving against free wind, if you run on a treadmill, there will be none.

The plane's velocity is not equal to that of the conveyor. Since we're assuming there is not resistance in the plane's wheels bearings, the conveyor has no effect on the plane.

[89coupe]

Originally posted by JordanEG6


well, like the riddle/problem states if in anycase the jets cause the plane to move forward (increase in speed), the conveyor will match it and still remain stationary, wont it?


Do you understand how a jet is propelled forward?

[Raz2]

Originally posted by Ekliptix


The plane's velocity is not equal to that of the conveyor. Since we're assuming there is not resistance in the plane's wheels bearings, the conveyor has no effect on the plane.

Exactly. Ekliptix is a :bigpimp:

:-)

- Rasmus

[JordanEG6]

Originally posted by Ekliptix


The plane's velocity is not equal to that of the conveyor. Since we're assuming there is not resistance in the plane's wheels bearings, the conveyor has no effect on the plane.


"This conveyor has a control system that tracks the planes speed and tunes the speed of the conveyor to be exactly the same "


that being written, can't you assume that the velocity will be the same IF the conveyor tunes itself to match the speed of the plane?

[89coupe]

Originally posted by JordanEG6



&quot;This conveyor has a control system that tracks the planes speed and tunes the speed of the conveyor to be exactly the same &quot;


that being written, can't you assume that the velocity will be the same IF the conveyor tunes itself to match the speed of the plane?

The speed of which the wheels are turning but what does that have to do with the forward motion of the plane?

[szw]

I disagree with this.

Originally posted by Ekliptix


The plane's velocity is not equal to that of the conveyor. S

but I agree with this, which means the above point doens't really matter.


Originally posted by Ekliptix


Since we're assuming there is not resistance in the plane's wheels bearings, the conveyor has no effect on the plane.

[Raz2]

what is meant is wheel speed.. which has nothing to do with VELOCITY!

- Rasmus

[962 kid]

Originally posted by JordanEG6



&quot;This conveyor has a control system that tracks the planes speed and tunes the speed of the conveyor to be exactly the same &quot;


that being written, can't you assume that the velocity will be the same IF the conveyor tunes itself to match the speed of the plane?

The speed of the WHEELS will = the speed of the conveyor belt.

[JayWang]

okay my bad

i think we can all agree that planes are not cars

and the wheels are not driven by the engines.

Let's read the problem again:

This conveyor has a control system that tracks the planes speed and tunes the speed of the conveyor to be exactly the same (but in the opposite direction).

along with the perfect controller assumption,
lets also assume that:

1) the purpose of the belt controller is to keep the plane "stationary".
effectivley a velocity of zero.

2) a dumbass didn't design the controller.
therefore it will measure the plane speed as a function of it's jet engine power.

an incorrect controller would be designed to measure plane speed as a function of it's wheel RPM (like a speedometer)

this is what a retard would do, kinda like when kippur let in that weak ass goal in the SO to Pisani. That was retarded.

i think in all vehicles, the speedometer measues speed as a function of wheel RPM.

but we are not talkign about speedometers here, we're talking about belt controllers.

so i stick by my answer

if the controller was designed properly and does it's job of keeping the plane stationary, then that the plane isn't taking off.

unless the controller was designed by a retard, then that shit isn't gonna get the job done and just cause alot of headaches. just like the flames on the power play

GO LEAFS GO

[Ekliptix]

Originally posted by JordanEG6



&quot;This conveyor has a control system that tracks the planes speed and tunes the speed of the conveyor to be exactly the same &quot;

that being written, can't you assume that the velocity will be the same IF the conveyor tunes itself to match the speed of the plane?

Alright let's go along with that.
Staged Events:
-The plane is just sitting there (0mph) so the conveyor spins at 0mph.
-The plane's engines provide a little thrust to and it moves 5mph. The conveyer starts spinning 5mph backwards to compensate.

Now, does the conveyor spinning backwards stop the plane from moving forward? The answer is no because the conveyer effects the speed of the tires on the plane. Since the speed of the tires have no effect on the plane the plane keeps moving forward. :poosie:

[Raz2]

http://forum.physorg.com/index.php?showtopic=2417&st=0

[Ekliptix]

Originally posted by szw
I disagree with this.



I think you're correct there.

[szw]

Originally posted by JayWang


1) the purpose of the belt controller is to keep the plane &quot;stationary&quot;. effectivley a velocity of zero.




Nowhere in the question does it state this. in fact it states nothing about keeping the plane stationary. It simply states 1) the plane moves forward.
2) the plane is on a conveyer belt moving backwards at the same speed.




Originally posted by JayWang


GO LEAFS GO

:goflames:

[Raz2]

ok, since this is a physics brain teaser friction is not allowed, its always a 'perfect world' in physics.

So lets take another similar example.

Some college kids took your civic and placed it out on a lake, the ice is SO cold that it has a mU value of 0, ie, NO MATTER HOW FAST OR FURIOUS YOUR SPIN YOUR WHEELS YOU WILL NOT MOVE.. now, you're smart, so you brought a hairdryer (a super deluxe GT TURBO one) and point it out the window - OMFG the car moves..

Get it?

- Rasmus

[Raz2]

oh, btw. fuck the leafs :D

:goflames: :goflames: :goflames: :goflames: :goflames:

[Weapon_R]

It'll only move if the hair dryer has vtech

[szw]

Also, JAYWANG,

I think it doesn't matter how your controller is designed. I think the conveyer belt could travel at twice the velocity of the plane and it still wouldn't make a difference.

[digi355]

I think she would take off. Whats the answer?

[gpomp]

where is super geo when you need him

[962 kid]

Originally posted by Raz2
ok, since this is a physics brain teaser friction is not allowed, its always a 'perfect world' in physics.

So lets take another similar example.

Some college kids took your civic and placed it out on a lake, the ice is SO cold that it has a mU value of 0, ie, NO MATTER HOW FAST OR FURIOUS YOUR SPIN YOUR WHEELS YOU WILL NOT MOVE.. now, you're smart, so you brought a hairdryer (a super deluxe GT TURBO one) and point it out the window - OMFG the car moves..

Get it?

- Rasmus

:werd: So basically, since the rotational speed of the wheels is equal to the rotational speed of the conveyor, the effect of the conveyor will negate all effects that the speed of the wheels may have on the aeroplane. But because the wheels are nothing more than a kickstand with wheels for an aeroplane, they don't have any effect on the speed at all, which only leaves the thrust of the engines to move the plane forward. I suppose you could kind of imagine it like a frictionless skateboard riding on the same type of conveyor belt... if you tie a rope to the person on the board and pull them (basically the force exerted by the jets), the person will move forward

[chris]

you are all wrong, it depends on the coefficent of the friction of the runway on the wheels. Here's a really crappy paint diagram to explain why. actually because were talking about an airplane, n would actually be L+n, but wat ever and Fc could be notarized as fk , but i dont feel like drawing another really crappy paint diagram

[nismodrifter]

Originally posted by Ekliptix


Vtec engages and there's a shitstorm of takeoffs.

:rofl: :rofl:

[Raz2]

exactly, perfect rope+skateboard analogy :)

- Rasmus

[962 kid]

Originally posted by chris
you are all wrong, it depends on the coefficent of the friction of the runway on the wheels. Here's a really crappy paint diagram to explain why

That doesn't prove anything :dunno:

[Raz2]

http://forums.beyond.ca/attachment.php?s=&postid=1302129

omfg

[Raz2]

962, oh but it does... that he is drunk off his ass and loves mspaint :)

- Rasmus

[szw]

no Chris, I would say you are wrong.

[JayWang]

[QUOTE]Originally posted by szw
[B]

Nowhere in the question does it state this. in fact it states nothing about keeping the plane stationary. It simply states 1) the plane moves forward.
2) the plane is on a conveyer belt moving backwards at the same speed.


read my post again.

i was stating my assumptions.

it's very common to state assumptions when solving problems

but alot of the time, people don't state their assumptions.

like how i don't need to state my assumption that you know how to read

or maybe i shouldn't be too quick to assume things.

[chris]

Originally posted by szw
no Chris, I would say you are wrong.
ok.... good argument. when l or n or watever notation i used is greater than w, the plane will take off. There's a lot of variables you have to take into account. if there's no friction between the runway and the wheels, the plane will take off, if fk or wateevr notation i used that counteracts forward movement is equal to forward movement the plane will not move and the plane will not lift off

[szw]

Originally posted by 962 kid


:werd: So basically, since the rotational speed of the wheels is equal to the rotational speed of the conveyor, the effect of the conveyor will negate all effects that the speed of the wheels may have on the aeroplane. But because the wheels are nothing more than a kickstand with wheels for an aeroplane, they don't have any effect on the speed at all, which only leaves the thrust of the engines to move the plane forward. I suppose you could kind of imagine it like a frictionless skateboard riding on the same type of conveyor belt... if you tie a rope to the person on the board and pull them (basically the force exerted by the jets), the person will move forward

While I think you have come to the correct conclusion, your method is flawed imo.

You are saying the conveyer belt cancels out the wheels effects on the plane, then the additional force from the jets move the plane.

People who argue that the plane dosn't move will say that once you turn on the engines and start moving faster, the conveyer belt moves faster to cancel it out. WHile this is true (that the conveyer speeds up), it doesn't have any effect.

[Raz2]

ok, once again, the conveyer belt could move at ONE GILLION LIGHTYEARS PER NANOSECOND AND IT WOULD STILL NOT CANCEL OUT THE JET PROPULSION AT ALL SINCE THIS IS A PHYSICS "EXPERIMENT" AND HAS NO FRICTIONAL FORCES BUILT INTO IT.

GOT IT?! Garr! :)

[ex1z7]

The conveyor wont do shit if the plane doesn't move initally.. If it matches the planes speed only in reverse - it'll simply make the wheels move quicker.. which doesn't have a whole lot to do with making the plane take off... the moving air makes the plane lift off if you want to get really basic, and if the plane isn't moving - just the wheels are - then no air is making it take off cus no lift is being generated ..

in short.

The plane isn't goin' anywhere.

[szw]

Originally posted by JayWang
[QUOTE]Originally posted by szw
[B]

Nowhere in the question does it state this. in fact it states nothing about keeping the plane stationary. It simply states 1) the plane moves forward.
2) the plane is on a conveyer belt moving backwards at the same speed.


read my post again.

i was stating my assumptions.

it's very common to state assumptions when solving problems

but alot of the time, people don't state their assumptions.

like how i don't need to state my assumption that you you can read

or maybe i shouldn't be too quick to assume things.

Very clever. I understand that it was an assumption you made, I'm simply saying it is an incorrect assumption.

[chris]

Originally posted by JayWang

GO LEAFS GO [/B]

hells yes, i saved a special picture just for you, stupid flames bandwagoners
http://members.shaw.ca/hewsond/goleafsgo.jpg

[Ekliptix]

Originally posted by ex1z7
The conveyor wont do shit if the plane doesn't move initally.. If it matches the planes speed only in reverse - it'll simply make the wheels move quicker.. which doesn't have a whole lot to do with making the plane take off... the moving air makes the plane lift off if you want to get really basic, and if the plane isn't moving - just the wheels are - then no air is making it take off cus no lift is being generated ..

in short.

The plane isn't goin' anywhere.

If the conveyer is only effecting the wheels then the plane will continue to go forward, no? So if the plane can continue to go forward the air going under the wings will increase and the plane will eventually take off.

[Raz2]

http://forums.beyond.ca/images/smilies/goflamesgo.gif

[962 kid]

Alright, I've drawn a slightly less crappy drawing to try and explain. I've divided up the entire diagram into the 2 different systems that will influence the motion and forces experienced by the plane

http://img516.imageshack.us/img516/5354/conveyor6dm.jpg

System 2 is composed of the conveyor belt and the wheels. Now because the conveyor belt and wheels are moving opposite to each other, they combined will have no effect on the plane, which leaves only system 1: the jets

[Raz2]

btw: this has to be one really, fucking, long, ass conveyer belt :)


- Rasmus

[szw]

It says click image for larger version...but I get a smaller version when I click. Therefore, the plane doesn't take off!

[chris]

Originally posted by Raz2
ok, once again, the conveyer belt could move at ONE GILLION LIGHTYEARS PER NANOSECOND AND IT WOULD STILL NOT CANCEL OUT THE JET PROPULSION AT ALL SINCE THIS IS A PHYSICS &quot;EXPERIMENT&quot; AND HAS NO FRICTIONAL FORCES BUILT INTO IT.

GOT IT?! Garr! :)
but in real life there is friction and as soon as you tell me either to ignore friction or calculate the coefficent of friction, i can give a diffenative answer. until then......
http://members.shaw.ca/hewsond/goleafsgo.jpg
hahahaha

[Raz2]

Original Post Removed. (Please read the Forum Rules and Terms of Use (http://forums.beyond.ca/articles.php?action=data&item=1) before posting again, or risk getting banned).

[szw]

Thats annoying.

[chris]

^^^thats just annoying, of course it has it's limitations as does other stuff, but without that knowledge it's impossible to calculate, thus my answer, in a perfect frictionless world (like the ones they give you in high school) yes it would take off. In the real world you would need a couple of extra variables to figure it out

[Strugari]

The aircraft will become airborne!

Return to the treadmill, but put a bicycle on it, with someone to hold it steady. As the speed of the treadmill increases, the wheels turn faster, but since it is being held steady. the bicycle does not move.

Now, have someone push the bicycle forward, off the front of the treadmill. The wheels turn faster to cover the additional terrain, but the bicycle does move forward.

The engines of the aircraft are the same as the individual pushing the bike. The wheels merely serve as a contact point with the ground. The aircraft will gain both ground and air speed and will take off, the conveyor will compensate for the ground speed, but not the airspeed.:thumbsup:

[Raz2]

dude, strap on some lollerskates and a jetpack. howevever, where are you gonna find a treadmill that will put out the right amount of "speed" determined from your jetpacks output?

....?

- Rasmus

[szw]

Originally posted by Raz2
dude, strap on some lollerskates and a jetpack. howevever, where are you gonna find a treadmill that will put out the right amount of &quot;speed&quot; determined from your jetpacks output?

....?

- Rasmus

Actually this is quite easy. Tune your jetpack to push you along at say 5mph on flat ground.

Set the treadmill to 5mph.

[JordanEG6]

Originally posted by 962 kid
Alright, I've drawn a slightly less crappy drawing to try and explain. I've divided up the entire diagram into the 2 different systems that will influence the motion and forces experienced by the plane

http://img516.imageshack.us/img516/5354/conveyor6dm.jpg

System 2 is composed of the conveyor belt and the wheels. Now because the conveyor belt and wheels are moving opposite to each other, they combined will have no effect on the plane, which leaves only system 1: the jets


hmmm...valid. but im still wondering. if the wheels are connected to the plane, and jets cause the plane to thrust, which is supposed to move the plane forward. wouldnt the thrust increase the speed of the wheels? and cause the belt to match the speed of the wheels?

like for example, a shopping cart's wheels are travelling 1000rpm on a treadmil (-1000rpm). if i push the cart with my hands (jets) to move it forward, wont it cause the wheels to move faster, thus causing the belt to move faster rendering system one usless? :dunno:

[szw]

Originally posted by 962 kid

http://img516.imageshack.us/img516/5354/conveyor6dm.jpg


Which way is your arrow pointing (conveyer belt direction)? I'm getting to my point about your explaination, but want you to answer this first.

[chris]

Originally posted by JordanEG6



hmmm...valid. but im still wondering. if the wheels are connected to the plane, and jets cause the plane to thrust, which is supposed to move the plane forward. wouldnt the thrust increase the speed of the wheels? and cause the belt to match the speed of the wheels?

like for example, a shopping cart's wheels are travelling 1000rpm on a treadmil (-1000rpm). if i push the cart with my hands (jets) to move it forward, wont it cause the wheels to move faster, thus causing the belt to move faster rendering system one usless? :dunno:
exactly, i dont know why this person thinks the wheels are seperate from the plane, the plane drives the wheels, 962 kid you need to start thinking this in terms of forces and newton's second law and not rotations of the wheel, it will start making a lot more sense

[JayWang]

962

i really like your diagram and you do bring a valid arguement (from a physics standpoint)

but

from a process control (chemical engineering) point of view, isn't the controller designed to negate the effects of the jet engine??

(read my other post, i assumed the belt controller was measuring plane speed AS A FUNCTION OF JET ENGINE PURPOLSION.)

that means the belt will always be "winning" (because of the controller) and compensate properly to prevent the plane from moving.

and for hte people trying to make analogies with treadmills and pushing people off, riding bikes or on lollerskates, just stop.

it's not hte same thing, since you don't have a control system tuning the speed of the treadmilll (converyer belt), as it receives feedback.