Plane and Treadmill

[NemoySpruce]

This thought experiment is making the rounds on the internet. Would you like to try? :)

----------------
Imagine a plane is sitting on a massive conveyor belt, as wide and as long as a runway, and intends to take off. The conveyer belt is designed to exactly match the speed of the wheels at any given time, moving in the opposite direction of rotation.

Can the plane take off?

[ninong]

This thought experiment is making the rounds on the internet. Would you like to try?


Imagine a plane is sitting on a massive conveyor belt, as wide and as long as a runway, and intends to take off. The conveyer belt is designed to exactly match the speed of the wheels at any given time, moving in the opposite direction of rotation.

Can the plane take off?

pag di ako busy at makakita ng nagpapa rent ng malaking conveyor,ita-try ko yan...:).pansamantal a,theoretical conclusion muna...

the plane cannot take off bec...

firstly,since the plane is not moving, its not creating more aerodynamic force forward (thrust)to offset the drag.in the experiment, thrust is equal to drag.it should be thrust >drag to fly the plane.

secondly,lift must be greater than weight.
in aerodynamics,lift will exist only if there is a moving air or fluid(air is consider a fluid bec of its composition)or the object is moving against the fluid.in the experiment, the plane is not moving forward against the air nor enough velocity of air is moving against the plane.bec of the above fact,lift can not exist and therefore,weight of the plane is >>lift created.

for many reasons,conveyor take off cannot satisfy the basic aerodynamic principle of weight= lift and thrust =drag to fly an object.
thats why engrs use large areas of space to build airports,naval vessels and airfields.kung pwede ang conveyor take off,lahat naka conveyor na lang pag lilipad.parang motoGP kapag magte-take-off. :)

just my conclusion based on my theory.

[NemoySpruce]

Nice one Ninong, you are probably correct., and that is almost the same answer I had initially :). However, wouldnt you say that speed is relative? and relative to the speed of the conveyor, the plane is accelerating its normal rate for takoff. Is it possible that enough lift will be generated by the movement of the wind caused by the movement of the conveyor belt? ...

and just to make it clear;

weight < (less than) lift and thrust (greater than) > drag to make an object fly. the conveyor belt affects land speed, and keeps it at zero. Airspeed is not directly affected.

[wired]

all is said...agree na lang ako...

[andres]

Etong hula ko... Yes. Lilipad yung eroplano.

Pero hindi ko yata ma-explain yung sagot ko.:O

Halimbawa, kung parang auto ang airplane, at yung pag-ikot nang gulong mismo ang nagpapatakbo sa kanya, siguro sasabihin ko na hindi nga magkaka-liftoff.

Pero, sa kaso ng airplane, yung jet engine (o propeller) mismo ang nagpapatakbo ng sasakyan; ang pag-ikot ng gulong ay consequence lamang ng paggalaw ng aircraft. Ibig sabihin, gagalaw lang ang conveyor belt kapag "gumagalaw" din ang eroplano, at wala itong epekto sa "amount of work" na ginagawa ng makina.

Pero.... paano naman magkakaroon ng "lift" kapag walang flow of air relative to the wings? (o meron ba??). Yan ang hindi ko alam.
:bonk:

OT - NemoySpruce, mahilig ka pala sa Dune.

[wired]

hmm...hindi po ang jet engine or propeller ang nagpapalutang sa eroplano...just what ninong had said...its aerodynamics...meani ng kailangan may dumadaang hangin sa pakpak ng eroplano para ito ay lumipad...

[wired]

mejo mali pala ang basa ko sa sagot mo bro andres...sorry hehehehhe

[wired]

pero...given na umandar ang jet engine or propeller..gagalaw din ang gulong...bakit? remember the law: for every given action there is an equal and opposite reaction? so kung aandar and propeller...itutulak nito ang eroplano...and nakapatong sa threadmill ang plane so aandar ang gulong at ang threadmill...pero hindi lilipad ang eroplano since there is no aerodynamic present...

[simor_buts]

like what everybody said, hindi lilipad ang eroplano. The plane will just stay where it is.
Ang velocity ng plane going forward ay maka-cancel lang ng velocity ng threadmill na going backward. Kailangan may air na sasalubong sa plane na may velocity kaparehas ng take-off speed ng plane.

Subukang gumamit ng escalator. salubungin ang direction ng escalator (pababa ka kung paakyat ang escalator and viceversa). Kailangan pareho ang bilis mo at ng escalator. Dahil magka-iba ang direksyon, mapapansin na hindi nagbabago ang pwesto mo relative sa earth o anumang bagay outside ng escalator.

Yan po ay aking pananaw lamang, sana po ay makatulong or lalong makapagpagulo sa utak ng taga-TF:D

[Stacie Fil]

This thought experiment is making the rounds on the internet. Would you like to try? :)

----------------
Imagine a plane is sitting on a massive conveyor belt, as wide and as long as a runway, and intends to take off. The conveyer belt is designed to exactly match the speed of the wheels at any given time, moving in the opposite direction of rotation.

Can the plane take off?

Sure it will fly. Give it a vertical lift off! Ha,ha,ha,:D :wink: :biglaugh: :toofunny:

Well, kidding aside, if I'm the pilot it probably will. He,he,he. I meant my answer is Yes Since it is on a tread mill and constantly rolling, then it is not flying but running fast.

Yet imagine if you can direct down both the elevator and wings, then you are adding your weight relative to speed. Its like a stone with thick string/cord connected to an end of a stick rotataing fast as a sling. The tire and the shock spring/absorber is also being pumped down. What if we suddenly cut the string? If instantaneously you will flipped the wing out up in opposite direction, you suddenly shall create a bump/jump effect. With your jet in full trust, guess its like similar situation to igniting/starting the engine out in space.

What do you guys think?

[reon]

If the "conveyor belt is designed to match the speed of the wheels at any given time" and moving in the opposite direction, then I suppose the plane will always stay in the initial position? So the plane won't fly because it just stays where it is. Tama ba?

[fisher]

Everytime na sasakay ako ng eroplano pinagmamasdan ko yung puwitan ng engine.Naobserbahan ko na may napakalakas na hangin na ibinubuga ang mga engine nito para ito at makakuha ng pwersa at umangat.'yung runway na basang basa ng tubig sa ulan ay natutuyuan ng husto dahil sa lakas ng hangin na lumalabas,sa palagay ko ay ang hangin malaking factor sa pag-angat ng eroplano at hindi ang pag-ikot ng mga gulong nito.At sa palagay ko rin ay ang lakas ng hangin na ibinubuga ng mga makina ang siyang natutulak sa eroplano para umusad at hindi na ang mga gulong nito dahil talo ng pwersa ng hangin ang hila ng mga gulong.So kahit na may conveyor pa na umiikot ng kontra sa ikot ng gulong ay makakalipad ang eroplano.Ito po'y obserbasyon ko lamang.Kung naging piloto sana ako alam ko ang tungkol dito kaya ito po'y haka haka ko lamang:D .

[simor_buts]

If the "conveyor belt is designed to match the speed of the wheels at any given time" and moving in the opposite direction, then I suppose the plain will always stay in the initial position? So the plane won't fly because it just stays where it is. Tama ba?

Our thoughts are parallel reon-san!

[wired]

Sure it will fly. Give it a vertical lift off! Ha,ha,ha,:D :wink: :biglaugh: :toofunny:

Well, kidding aside, if I'm the pilot it probably will. He,he,he. I meant my answer is Yes Since it is on a tread mill and constantly rolling, then it is not flying but running fast.

Yet imagine if you can direct down both the elevator and wings, then you are adding your weight relative to speed. Its like a stone with thick string/cord connected to an end of a stick rotataing fast as a sling. The tire and the shock spring/absorber is also being pumped down. What if we suddenly cut the string? If instantaneously you will flipped the wing out up in opposite direction, you suddenly shall create a bump/jump effect. With your jet in full trust, guess its like similar situation to igniting/starting the engine out in space.

What do you guys think?

this won't happen...still no aerodynamics...it is just very simple...no aerodynamics no flying airplane...even if you suddenly flipped the wing flip out up...no wind and drag opposes the plane...so no aerodynamic...no flying plane...

[andres]

this won't happen...still no aerodynamics...it is just very simple...no aerodynamics no flying airplane...even if you suddenly flipped the wing flip out up...no wind and drag opposes the plane...so no aerodynamic...no flying plane...

Totoo yan... importante yung aerodynamics.

Pero palagay ko may ibang paraan ng pag-iisip tungkol dito. Ang kundisyon lamang ay " the conveyor belt is designed to match the speed of the wheels at any given time". Walang kundisyon tungkol sa speed of the plane... Kaya palagay ko, posible nga.

[wired]

nawala ung isang post ko...mali ata ang nabura ng moderator...

eto yung additional...imagine yourself running on a road...while you are running, wind passes opposite you...now try running on a treadmill...no matter how fast you run...now ind opposes you...that simple...

and bro andres...kahit gano kabilis ang plane magmamatch ung speed ng treadmill(nasa condition yun na binigay diba?) so hindi aalis ang plane sa position nya so still no aerodynamics..:)

[liong]

ok to ah......:D nice one....:D

sa aking nakita at pagkakaintindi...hin di aangat ang eroplano... kasi walang LIFT AND DRAG THEORY na mangyayari dahil same lang ang bilis ng konbeyor at eroplano.....

eto po ang link..... ating silipin
http://www.pilotsweb.com/principle/liftdrag.htm

sana maintindihan natin....

[Stacie Fil]

this won't happen...still no aerodynamics...it is just very simple...no aerodynamics no flying airplane...even if you suddenly flipped the wing flip out up...no wind and drag opposes the plane...so no aerodynamic...no flying plane...


There should be aerodynamics, it has aerodynamics because there were counter flows of speed and directions. The plane is only seen stationary, but the highspeed rotating conveyor at this case is the one creating, Try in actual getting close to a thick belt at high speed or throwing dust in it. It shall reveal not only aero flow but counter push. It only happens in this case that the engine trust is the one pushing, making the plane tire to get in contact with the speeding ground/conveyor + friction. If instantaneously the contact shall break, the plane is already considered flying. Thus changing the direction of the force, instead of downward, then its a lift.

In similar fashon, i guess thats the same way you study aero in a tunnel.

[wired]

There should be aerodynamics, it has aerodynamics because there were counter flows of speed and directions. The plane is only seen stationary, but the highspeed rotating conveyor at this case is the one creating, Try in actual getting close to a thick belt at high speed or throwing dust in it. It shall reveal not only aero flow but counter push. It only happens in this case that the engine trust is the one pushing, making the plane tire to get in contact with the speeding ground/conveyor + friction. If instantaneously the contact shall break, the plane is already considered flying. Thus changing the direction of the force, instead of downward, then its a lift.

In similar fashon, i guess thats the same way you study aero in a tunnel.

yes...there is aerodynamic...on the belt but not on the wings...and given the condition THE CONVEYOR IS DESIGNED TO MATCH THE SPEED OF THE WHEELS AT ANY GIVEN TIME...it will be VERY IMPOSSIBLE for the wheels to break contact to the conveyor...

peace out...

[ninong]

there are 4 aerodynamic forces acting on a plane.1)thrust, 2)drag, 3)lift and 4) weight and to fly the airplane.starting from rest,1 must be greater than 2 and 3 must be greater
than 4.

thrust force is created when the engines suck air,compress it and mix with high octane fuel and burn the mixture and ignites the mixture.the expanded gas blast out the nozzle and it push the engine forward.
if the plane is in stationary position,i think it cant sucks the amount of air (and cant raise the air pressure) needed for the blast to keep the plane flying bec of the limited headwind.maybe tatalsik sya sa conveyor pero di magsusustain ng lipad like yung pet bottle rocket.

lift is created when air(fluid) of different directions acts on the wings which are shaped and designed for the purpose.commercial airplanes have take-off speed of about 240-280km/hr and with that take-off velocity,imagine the airspeed and pressures that are acting on the wings and compare if the plane is not moving.bec airspeed is too slow,it cant produce a lift greater than the weight(363,000kg plus baggage for a BOEING 747).

[andres]

Everything that has been said about thermodynamics, drag, lift, etc., may be totally correct, but is totally irrelevant to the question at hand. The plane will take off. I'll try to explain my answer.

Let's revist the original proposition:

Imagine a plane is sitting on a massive conveyor belt, as wide and as long as a runway, and intends to take off. The conveyer belt is designed to exactly match the speed of the wheels at any given time, moving in the opposite direction of rotation.

Can the plane take off?


And I will again state this fact: In an airplane, the rotation of the wheels has no direct bearing on the motion of the plane -- it is not connected to the motor mechanism but essentially "freewheels". This is in contrast to a car, where the movement of the wheels does have an effect on the motion of the vehicle, the wheels being connected to the engine via the whatchamacallit -- crankshaft? I don't know the terminology, sorry.

Anyway, on to the thought experiment. I think most of the error arises in the visualization of the situation. Like me, when I first read this I imagined a rather short conveyor belt, roughly the length of the plane itself. This then leads to the imagination/supposition that in this experiment, the plane will not move forward in relation to the ground. But this is an erroneous assumption. We read above that the "plane is sitting on a massive conveyor belt, as wide and as long as a runway".

The plane engine starts. This causes the plane to move forward a bit. The movement of the wheels in turn activates the conveyor belt to move in the direction opposite of the wheels (at exactly the same speed). But since the wheels are "free", this doesn't have any effect on the movement of the plane. In fact, the plane just goes forward and forward, as it would normally do, accelerate (as would the conveyor), until finally acquiring enough lift for take off... just as it would normally! The only consequence of having the conveyor is making the wheels spin madly at twice the normal speed. Do you buy it? ;)

[Dax]

The plane engine starts. This causes the plane to move forward a bit. The movement of the wheels in turn activates the conveyor belt to move in the direction opposite of the wheels (at exactly the same speed). But since the wheels are "free", this doesn't have any effect on the movement of the plane. In fact, the plane just goes forward and forward, as it would normally do, accelerate (as would the conveyor), until finally acquiring enough lift for take off... just as it would normally! The only consequence of having the conveyor is making the wheels spin madly at twice the normal speed. Do you buy it? ;)Hmm...sabi sa original proposition:

"The conveyer belt is designed to exactly match the speed of the wheels at any given time, moving in the opposite direction of rotation."

So the plane won't move forward talaga...as I understand it. Hence, it won't be able to take off.

Mahirap imaginin ang isang malaking bagay katulad ng eroplano so kung pwede palitan ko muna ng tao, na tumatakbo sa horizontal "escalator" or whatever you call it, yung makikita natin sa Ebisu & Tokyo stations at sa Narita airport. Assuming stationary ito, if you run on it as fast as you could and jump...you would land a few meters away from the point of take off right? Parang long jump ni Lydia de Vega. (or a plane taking off from a normal stationary runway)

Now, assuming that you turn it on, and again run as fast as you could...but the speed of the belt adjusts to match yours on the opposite direction...even if you jump you'll just land at the same spot (not at the machine, but same spot underneath the machine :D) where you took off. (or the plane in the proposition) Tama ba mga aerodynamics experts? :D

[ninong]

Everything that has been said about thermodynamics, drag, lift, etc., may be totally correct, but is totally irrelevant to the question at hand.

of course relevant dahil yun ang thery na suporta sa sagot dahil nga di naman tayo gumawa ng actual na experiment...hanggan g theory lang.

pangit naman na basta na lang magsasabi na lilipad o hindi lilipad na hindi ipinapaliwanag.

now,talking about fact.the fact is no airport,airbase,airf ield and aircraft carrier in the world uses a conveyor for airplanes to take-off bec its not possible...thats the fact!

[NemoySpruce]

of course relevant dahil yun ang thery na suporta sa sagot dahil nga di naman tayo gumawa ng actual na experiment...hanggan g theory lang.

pangit naman na basta na lang magsasabi na lilipad o hindi lilipad na hindi ipinapaliwanag.

now,talking about fact.the fact is no airport,airbase,airf ield and aircraft carrier in the world uses a conveyor for airplanes to take-off bec its not possible...thats the fact!

sir ninong, I think you misunderstood pareng andres, I think what he means is that in his explanation, the aerodynamics need not be considered. He is saying that the wheels will just spin faster than normal and still allow the plane to move forward. So the plane will expend more energy, but still move forward and eventually gain enough speed to produce adequate lift for take off. of course aerodynamics is relevant.

I think the point of this thought experiment is to test our understanding of the basic principles of flight, and physics. Puro hulaan lang ito, dahil there is no way to test any of our assumptions, but if you can present a good argument then you may convince other people.

[ninong]

sir ninong, I think you misunderstood pareng andres, I think what he means is that in his explanation, the aerodynamics need not be considered. He is saying that the wheels will just spin faster than normal and still allow the plane to move forward. So the plane will expend more energy, but still move forward and eventually gain enough speed to produce adequate lift for take off. of course aerodynamics is relevant.

I think the point of this thought experiment is to test our understanding of the basic principles of flight, and physics. Puro hulaan lang ito, dahil there is no way to test any of our assumptions, but if you can present a good argument then you may convince other people.


sorry bro kung namis-interpret.friday na kasi...sa weekend na naka set ang utak ko....peace.

[NemoySpruce]

Hehe, aku din eh. pasko pa kaya nahihirapan akong mag concentrate sa trabaho. gusto ko nang magbakasyon!! peace din po.




sorry bro kung namis-interpret.friday na kasi...sa weekend na naka set ang utak ko....peace.

[andres]

Salamat, NemoySpruce, sa clarification. Yun nga ibig ko sabihin. Hehehe, kailangan nga magrelaks tayo mga kaibigan dahil hindi daw mabuti ang stress... hep teka andyan na naman si boss :type:

[Little Johnny]

interesting topic....

andres & I are on the same page.

i think the plane will fly, as it normally would, given the circumstances. andres' (and my) argument is that "What makes the plane move (the prime mover) is the thrust created by the jet engine, and not the wheels. The wheels are freewheeling, just to make the plane able to taxi around the airport (maybe :confused: )."

now think about this. nuong bata pa ako, naalala ko yung ginawa ko... may bisikleta ako na under repair, nakataob. yung gulong sa unahan, freewheeling. pwede mo paikutin kahit gaano kabilis. habang umiikot yung gulong, sinubukan kong magdikit ng gulong ng isang laruang kotse (freewheeling din ang mga gulong).... umikot din, sabay sa pag-ikot ng gulong ng bike.... in opposite directions. habang umiikot ang mga gulong ng kotse at bike (with the same linear speed), sinubukan kong itulak yung laruang kotse pa-abante...... umusad.

from this observation, I can conclude that with an additional push (thrust), the plane will move forward (relative to the ground), create lift and fly... the wheels can spin as crazy as they could, but it won't matter.

My opinion. Watcha think?:cool:

[Dax]

andres & LJ,

I understand your "freewheeling" thing, that the wheels themselves don't move the plane but the jet engines' thrust do. However, as the jets' thrust move the plane, so do the wheels' rotation since they carry the plane. And therefore you still cannot deny/ignore the wheels' motion. So to repeat again the second sentence...
The conveyer belt is designed to exactly match the speed of the wheels at any given time, moving in the opposite direction of rotation.
Let:
v1 = plane's velocity
v2 = wheels' velocity
v3 = conveyor belt's velocity (opposite direction)

v2 = v3 is given in the above quote
v1 = v2 is obvious, the plane can't travel faster than the wheels. :D

Therefore v1 = v3. Hence the plane won't be able to take off.

Or am I missing something? How about my "running man" comparison? :confused:

[liong]

teka.. teka...... masakit na ulo ko dito......... inum muna ko ng gamot..

according sa nabasa ko.... kelangan ng counter force na magrereact dun sa wings
ng eroplano... at ito ang makakapagpaangat sa kanya....

according sa given..ang ating eroplano ay nakapatong sa conveyor..at ang gulong
nito ay tumatakbo with respect sa bilis ng takbo ng conveyor... kung ganun ang
sitwasyon, saan kukuha ng counter force na nagmarereact dun sa wings para umangat?

kung sasabihin natin sa engine ang pagbabasihan.. sa tingin ko kelangan natin ng
super engine para lang umangat ang ating eroplano....parang katulad ng engine ng space
shuttle.... pero kung ang gagamitin lang ay normal na engine na ginagamit ng
mga eroplano...... walang pagangat na mangyayari dito.....

@LJ... di ba sinabi mong tinulak mo... ayun ang extra force, ayun yung ibig kong
sabihin dun sa super engine according sa problem.... di tinukoy kung anung engine ang gamit... so lets assume na normal aircraft engine lang yun....at walang extra power

kaya ang sa akin ay di pa rin ito aangat......

inum ulit ako gamot..... have a nice weekends mga bro!

[ninong]

subukan kaya natin sa sarangola.medyo may kaibahan pero parang hawig na rin sa sinabing exp ni NS.magaan lang yun at maliit kaya kayang kaya natin paliparin.

expt 1-1
ihagis ng bata#1(heto yung take off speed) ang sarangola sa ere at sabay itatakbo ng bata#2 ang pisi na kinakabitan ng sarangola.yung pull ng pisi bale ang engine kung ikukumpara sa airplane.lilipad kaya? syempre...gawain ko yan noong bata pa ako.may hangin na sasalubong kasi sa edge ng shoulder ng sarangola

expt 1-2

ihagis ng bata #1 ang sarangola habang nakasakay sa ground escalator tulad sa narita or sa threadmill sabay takbo ang bata#2 na nakasakay din sa threadmill o escalator.bilis ng takbo ng mga bata ay sing bilis ng takbo ng escalator threadmill.lilipad kaya?parang hindi yata dahil walang sasalubong na hangin sa sarangola.yung hangin na yun yata ang lift na sinasabi.

[Little Johnny]

another viewpoint....

I think the wheels are irrelevant in a plane's take-off. I think the plane can move even without its wheels. The wheels are there to minimize friction (and facilitate ground maneuvering of course). Remember that the spinning of the wheels does not have any affect on the movement of the plane. So that means there is nothing (there may be something, but not enough) to counteract the force created by the engine's thrust. Without an equal and opposite reaction to a force, work can be done. Thus, the plane will move.

[Little Johnny]

@LJ... di ba sinabi mong tinulak mo... ayun ang extra force, ayun yung ibig kong
sabihin dun sa super engine according sa problem.... di tinukoy kung anung engine ang gamit... so lets assume na normal aircraft engine lang yun....at walang extra power

kaya ang sa akin ay di pa rin ito aangat......

inum ulit ako gamot..... have a nice weekends mga bro!

sa tingin ko, ang una dapat mapag-usapan ay kung gagalaw ba (relative to the stationary ground) ang eroplano. kasi kapag gumalaw, pwede na natin i-assume na magpapatuloy ito until take-off. tama po ba ang opinion ko?

@liong, agree ako na kelangan ng "extra power" nung plane, but only during start-up. siguro medyo mas matagal lang aardar yung makina bago maka-achieve ng movement, pero hindi naman siguro kelangan ng "super engine". These aircraft engines are more than enough to do the job.

[ninong]

another experiment 2-1

simple algebra,since yung ikot ng wheels ay equal sa counter na ikot ng conveyor,pwede natin silang i-cancel( a-b-=0,a=b,where a ikot ng whhels and b ikot ng conveyor)

since na delete na sila,pwede na rin silang alisin physically sa experiment so.neutralize naman nila ang isat-isa kaya di na kailangan pareho.
ipapatong na lang natin ang plane sa asphalt na runway.lilipad kaya?hindi yata no?hehehehe:D :D :D

[ninong]

Without an equal and opposite reaction to a force, work can be done. Thus, the plane will move.

of course it will move...as ive said sa previous post ko,tatalsik sya. di nmn sya naka bolt sa ground.yung tao nga,mahipan lang ng hangin sa bagyo, napapagalaw.pero di naman movement ang sinasabi sa experiment kundi ...will the plane take off daw?its yes or no.

[liong]

di pa rin lilipad....:D

kasi nga walang counter force dun sa wings ng eroplano dahil di sya umaalis sa pwesto at equal ang bilis ng gulong at conveyor............ :D at kahit itodo ang engine to the maximum level wala pa ring counter force sa wings para umangat......:O

nadehydrate na ata ako dito.............GRR RRRRRRRR:D

[simor_buts]

eto po ang link..... ating silipin
http://www.pilotsweb.com/principle/liftdrag.htm

sana maintindihan natin....

di pa rin lilipad....:D

kasi nga walang counter force dun sa wings ng eroplano dahil di sya umaalis sa pwesto at equal ang bilis ng gulong at conveyor............ :D at kahit itodo ang engine to the maximum level wala pa ring counter force sa wings para umangat......:O

nadehydrate na ata ako dito.............GRR RRRRRRRR:D

you are absolutely correct Prof. Liong... Your link has provided us a more detailed and well-explained article that can give us an explanation about this phenomenon called "The Plane and The Threadmill".... paano nga ulet yun ser!!!:D

Relak ka na lang muna ser, nakakaubos ng braincells ang thread na 'to.....


plane's direction -------->

. ____________________
D__________l_l______
l__________________O-/
__________d_d_______ ____________________ _________
O___________________ ____________________ _________O

<--------- threadmill's surface direction

pasensya na po sa tora-tora ko (nai-imagine nyo ba?:scratch: ) bumibyahe po kasi yung mga BOEING 747's ko, yung bago kong AIRBUS naman next month pa dating so pagdamutan na lang po natin.:)

let's think small in order to undestand this. A man running in a threadmill does not go anywhere, he just stays in one spot. If this is a plane, this plane will not fly. The plane must move through a fluid, which is air, or place a large electric fan in front of the plane that can blow air at the speed of plane's take-off velocity... hehehe

[andres]

Mukhang hindi yata tayo gaanong nagkakaintindihan mga pards... susubukan ko uling magpaliwanag... (LJ, parehong-pareho tayo ng iniisip)

Napakaganda ng illustration na ginawa mo, simor_buts. Sana okey lang sa iyo na gamitin ko para ipaliwanag ang ibig kong sabihin.

Ganito yon....



8599


Magkakaroon ng 3 consequences (in sequence):
1. The action of the propeller causes the plane to move forward
2. Since the plane moves forward, contact of the wheels with the conveyor causes the wheels to rotate (of course)
3. Since the plane’s wheels rotate, the conveyor gets activated, turning with an equal speed in the opposite direction (as shown above)

Sana lahat tayo agree sa tatlong punto sa itaas.


Ngayon etong sinasabi kong mangyayari susunod:


8600


Anong nangyari?
Nothing, the plane just keeps moving!?
Imposible ba?

Well, hindi, sa aking palagay. Dahil nga, freewheeling ang gulong ng plane: kahit na anong ikot nung treadmill sa opposite direction (green), magiging epekto lamang ay ang mas mabilis na pag-ikot ng gulong (blue); walang epekto ang pag-ikot ng gulong (blue) sa paggalaw ng eroplano (red). To use Dax’s terminology (see post #29), in this case v1 does not equal v2.


8601


And to answer ninong’s earlier post (#23), the fact that no airfield uses a giant conveyor belt as a runway is not because the planes cannot take off, but because the conveyor belt will have no effect on the take-off (in other words, the conveyor would have to be the same length as a normal runway).

Eto ay opinion ko lang po...;) peace!

[Dax]

Mukhang hindi yata tayo gaanong nagkakaintindihan mga pards... susubukan ko uling magpaliwanag... (LJ, parehong-pareho tayo ng iniisip)

Napakaganda ng illustration na ginawa mo, simor_buts. Sana okey lang sa iyo na gamitin ko para ipaliwanag ang ibig kong sabihin.

Ganito yon....



8599


Magkakaroon ng 3 consequences (in sequence):
1. The action of the propeller causes the plane to move forward
2. Since the plane moves forward, contact of the wheels with the conveyor causes the wheels to rotate (of course)
3. Since the plane’s wheels rotate, the conveyor gets activated, turning with an equal speed in the opposite direction (as shown above)

Sana lahat tayo agree sa tatlong punto sa itaas.Oops...wait! Dito magkaiba ang interpretation natin ng proposition andres...

Original:
The conveyer belt is designed to exactly match the speed of the wheels at any given time, moving in the opposite direction of rotation.

Para sa 'yo, ang ibig sabihin ng sa itaas ay: ang rotation ng gulong ng eroplano ang nagpapatakbo sa conveyor belt. That's what you wrote in 3. above right?

Ok, para sa akin naman ang ibig sabihin ng original proposition ay:
The conveyor belt adjusts its speed to match that of the plane's wheels, in the opposite direction.

Walang sinasabi ang proposition na ang movement ng gulong ang mismong nagpapa-andar sa conveyor belt! Hence, it would be but natural to say that the movement of the conveyor belt must be independent to that of the wheels (separately controlled), and therefore kahit anong bilis ng takbo ng eroplano...di pa rin siya aabante kasi nga bibilis din ang conveyor belt.

Now, how do we know which interpretation is correct? We can't, unless we ask the one who wrote it. :p

Conclusion: the plane would or would not be able to fly depending on the interpration of the proposition.

p.s. the best ang illustration ni simor

[simor_buts]

Napakaganda ng illustration na ginawa mo, simor_buts. Sana okey lang sa iyo na gamitin ko para ipaliwanag ang ibig kong sabihin.


p.s. the best ang illustration ni simor

Salamat!

Dozo! use it anytime.:)

[liong]

Salamat!

Dozo! use it anytime.:)

sir simor... ayos ang illustration mo ah......:p OT...

sayang malaki masyado itong problem natin......masyadong magastos kapag
experiment pa........:D

sa 3D kaya natin daanin........hihihi hi:p

di pa rin lilipad........:D

[simor_buts]

sa 3D kaya natin daanin........hihihi hi:p

di pa rin lilipad........:D

hehehe....　kahit ilang 'D' yata ang gamitin natin mukhang hindi pa rin lilipad:D

[Little Johnny]

ipapatong na lang natin ang plane sa asphalt na runway.lilipad kaya?hindi yata no?hehehehe:D :D :D

i think so..... on a frictionless surface....... but since there is no such thing, hence the wheels...:D

[Little Johnny]

an event is composed of a cause and an effect. along with it, some consequences take place, by-products that has no bearing on the event.

in a normal situation, let:

event = the plane's take-off
cause = thrust produced by the jet engine
effect = the plane will move forward, achieve the desired velocity and come to a flight
by-product = the wheels rolling... (with the heavy plane's weight pinning him down on the ground, he hasn't much of a choice:D)

in the experiment, the cause & effect are still there. the only thing changed are the by-products (with the addition of a conveyor running as fast as the wheels on the opposite direction)

therefore, the event will still take place.....

the plane will take off.

i hope i'm making sense here.....:O

[andres]

Para sa 'yo, ang ibig sabihin ng sa itaas ay: ang rotation ng gulong ng eroplano ang nagpapatakbo sa conveyor belt. That's what you wrote in 3. above right?

No, actually this is not what I meant.


Ok, para sa akin naman ang ibig sabihin ng original proposition ay:
The conveyor belt adjusts its speed to match that of the plane's wheels, in the opposite direction.

This is exactly what I mean. We agree on this one.
But still, the plane will fly :)

Okay... I have a side question... what if we have a plane taxiing down the treadmill/runway while the treadmill is off (in other words, same situation as on "solid ground"). And then suddenly, we turn on the treadmill (backwards in the opposite direction, to match the speed of the wheels, etc.). What would happen next? :confused:

[NemoySpruce]

Okay... I have a side question... what if we have a plane taxiing down the treadmill/runway while the treadmill is off (in other words, same situation as on "solid ground"). And then suddenly, we turn on the treadmill (backwards in the opposite direction, to match the speed of the wheels, etc.). What would happen next? :confused:


tingin ko po, assuming the treadmill instantly matches the speed of the wheels, the airplane's speed relative to the ground will equal zero. The airplane's speed relative to the surface of the treadmill will remain the same. The airplane's acceleration will equal zero.

[ninong]

Magkakaroon ng 3 consequences (in sequence):
1. The action of the propeller causes the plane to move forward

i disagree bec the experiment said>>>The conveyer belt is designed to exactly match the speed of the wheels at any given time, moving in the opposite direction of rotation.
action of the propellers to push the plane forward is thru the wheels bec it is still on the ground and not on the air.any rotation by the wheels caused by the action of the propeller will be counter by the conveyor at any given time.meaning, the plane will be at point 0 meter at any given time as long as it is on the ground.if the plane is designed to elevate at point 0 meter ala UFO or ala superman,then it can fly but its not designed that way.

2. contact of the wheels with the conveyor causes the wheels to rotate (of course)

true if the plane is moving but its is not bec it will remain at point 0 meter at any given time bec of this>>>>The conveyer belt is designed to exactly match the speed of the wheels at any given time, moving in the opposite direction of rotation.
it did not mentioned though that the conveyor is rotating or being rotated by the rotation of the wheels.it said,the conveyor is DESIGNED to match the speed of the wheels.there may be a seperate motor that is acting on the conveyor in order for it to rotate.just like a man can not make a threadmil to rotate just bec of his foot frictional contact with the belt.



3. Since the plane’s wheels rotate, the conveyor gets activated, turning with an equal speed in the opposite direction (as shown above)

so here,we see an airplane with propellers/engines working at the designed take-off speed---sitting on a massive conveyor that rotates counter forward at 0 meter from the starting point.
here,we see the thrust force produced by the engines/propellers that is being transfered thru the wheels become 0 bec it is being offset by the conter movement of the conveyor.
since its not moving,where is the necesary headwind velocity or the airspeed that is supposed to act on the wings?wala.kaya walang lift.walang lipad kung walang lift...walang lift kung walang enough airspeed na mag act sa wings.walang airspeed kung walang groundspeed.walang ground speed kung di makaka rotate forward ang mga gulong.



And to answer ninong’s earlier post (#23), the fact that no airfield uses a giant conveyor belt as a runway is not because the planes cannot take off, but because the conveyor belt will have no effect on the take-off (in other words, the conveyor would have to be the same length as a normal runway).

i respect your conclusion sir but i disagree!
kung makaka lipad ang airplane sa expt na ito,makakalipad di sya kahit sa 1 sqm na conveyor .ito ay dahil di naman kikilos forward ang plane dahil ang sabi sa expt ay The conveyer belt is designed to exactly match the speed of the wheels at any given time, moving in the opposite direction of rotation.


heto ay opinion ko lang din po...;) peace!

[liong]

Magkakaroon ng 3 consequences (in sequence):
1. The action of the propeller causes the plane to move forward

i disagree bec the experiment said>>>The conveyer belt is designed to exactly match the speed of the wheels at any given time, moving in the opposite direction of rotation.
action of the propellers to push the plane forward is thru the wheels bec it is still on the ground and not on the air.any rotation by the wheels caused by the action of the propeller will be counter by the conveyor at any given time.meaning, the plane will be at point 0 meter at any given time as long as it is on the ground.if the plane is designed to elevate at point 0 meter ala UFO or ala superman,then it can fly but its not designed that way.

2. contact of the wheels with the conveyor causes the wheels to rotate (of course)

true if the plane is moving but its is not bec it will remain at point 0 meter at any given time bec of this>>>>The conveyer belt is designed to exactly match the speed of the wheels at any given time, moving in the opposite direction of rotation.
it did not mentioned though that the conveyor is rotating or being rotated by the rotation of the wheels.it said,the conveyor is DESIGNED to match the speed of the wheels.there may be a seperate motor that is acting on the conveyor in order for it to rotate.just like a man can not make a threadmil to rotate just bec of his foot frictional contact with the belt.



3. Since the plane’s wheels rotate, the conveyor gets activated, turning with an equal speed in the opposite direction (as shown above)

so here,we see an airplane with propellers/engines working at the designed take-off speed---sitting on a massive conveyor that rotates counter forward at 0 meter from the starting point.
here,we see the thrust force produced by the engines/propellers that is being transfered thru the wheels become 0 bec it is being offset by the conter movement of the conveyor.
since its not moving,where is the necesary headwind velocity or the airspeed that is supposed to act on the wings?wala.kaya walang lift.walang lipad kung walang lift...walang lift kung walang enough airspeed na mag act sa wings.walang airspeed kung walang groundspeed.walang ground speed kung di makaka rotate forward ang mga gulong.



And to answer ninong’s earlier post (#23), the fact that no airfield uses a giant conveyor belt as a runway is not because the planes cannot take off, but because the conveyor belt will have no effect on the take-off (in other words, the conveyor would have to be the same length as a normal runway).

i respect your conclusion sir but i disagree!
kung makaka lipad ang airplane sa expt na ito,makakalipad di sya kahit sa 1 sqm na conveyor .ito ay dahil di naman kikilos forward ang plane dahil ang sabi sa expt ay The conveyer belt is designed to exactly match the speed of the wheels at any given time, moving in the opposite direction of rotation.


heto ay opinion ko lang din po...;) peace!

correct......:D bravo ninong...:D
di pa rin lilipad...

[infinite_trial]

i think i get andres' point (& LJ's) and i agree with the explanation

the wheels only have only minimal, if not irrelevant, effect on the plane's ability to take off. the plane's engine is causing it to move forward, not the wheel (so i think the question is flawed from the beginning). so kung ilalagay natin ito sa makatotohanang scenario, the speed of the plane (caused by the engine) = speed of the treadmill in the opposite direction, with enough air to provide lift...the plane would be still able to take off.

but if the wheels are powered like a car's...then the airplane would remain stationary thus causing friction...that would add weight and drag to the plane, which would cause it not to take off.

[ninong]

infinite trial said....

the wheels only have only minimal, if not irrelevant, effect on the plane's ability to take off.
correct

the plane's engine is causing it to move forward, not the wheel (so i think the question is flawed from the beginning).
correct again

so kung ilalagay natin ito sa makatotohanang scenario, the speed of the plane (caused by the engine) = speed of the treadmill in the opposite direction,....
korek ulit...but add ko lang na ang speed ng plane ay ang thrust force na gawa ng engines ay na-trasfer sa mga wheels.walang mechanical gears na nagta-trasfer na tulad sa car pero ang position ng airplane,presence at design ng wheels ang nagta-transfer sa thrust force na yun.


....with enough air to provide lift...the plane would be still able to take off.

wala ngang enough air dahil naka stationary ang plane.therefore walang lift.
as the expt said...The conveyer belt is designed to exactly match the speed of the wheels at any given time, moving in the opposite direction of rotation,
the plane will not move forward and therefore there will be no enough headwind or air velocity to act against the wings.without enough airspeed,lift is imposible.
airplanes' take-off speed is 240-280km/hr.imagine the amount of force of air acting on the wings at that fast speed.if the plane is not moving forward near that speed,lift is impossible.
the weight of a boeing 747 is about 363,000 kg.paano aangat ang bigat na yan kung di bubwelo pasulong para kumuha ng hangin. unless kung may rocket to nakakabit like space shuttle.

[ninong]

Okay... I have a side question... what if we have a plane taxiing down the treadmill/runway while the treadmill is off (in other words, same situation as on "solid ground"). And then suddenly, we turn on the treadmill (backwards in the opposite direction, to match the speed of the wheels, etc.). What would happen next? :confused:

my theory is di pa rin lilipad.ganito ang theory ko kung bakit lumilipad ang eroplano.

ang pinaka-importanting factor sa paglipad ng airplane ay ang air na mag-aact sa mga wings nito (ito yung tinatawag na lift sa aerodynamics).ang engine ay nagpo-produce ng force (heto yung thrust)para ang plane ay sumibat pa-forward at salubungin ng hangin para ito lumutang.magkaiba ang principle ng car at airplane.

ang engine ng car ay nagpo-produce ng force na tinatrasfer ng mechanical gears sa mga wheels para ito mag move forward o backward.meaning,dir etsang pinapatakbo ng engine ang mga wheels sa tulong ng mga gears.

ang airplane naman,ang trabaho lang ng engines ay magproduce lang ng forward force o boost para may hangin na sumalubong sa mga wings.hindi ang trabaho ng engines ang direktang nagpapalutang sa plane kundi ang hangin na sumasalubong sa mga pakpak na nagyayari dahil sa mabilis na thrust na gawa ng mga engines na ito.
kapag nasa itaas na,ang takbo ng makina ay rekta.walang high rev o low rev. meaning,kapag babagalan ang eroplano,hindi pwedeng bagalan ang takbo ng makina.ang kinokontrol ay ang hangin na nag aact sa mga wings or dinadagdagan lang ang drag. heto yung parang kabyo na ginagalaw ng pilot sa kakpit.dito ay may mga palikpik sa pakpak ang tumatayo para kontrahin ang hangin.

kapag nasa ground pa,kailangan ang mabilis na bwelo para may sumalubong na hangin at maka buo ng sapat na lift force at malapasan ang downforce o yung weight ng eroplano at gravity.
kung di makaka bwelo,imposibleng umangat ito dahil wala ngang sapat hangin na mag aact sa wings.

[infinite_trial]

korek ulit...but add ko lang na ang speed ng plane ay ang thrust force na gawa ng engines ay na-trasfer sa mga wheels.walang mechanical gears na nagta-trasfer na tulad sa car pero ang position ng airplane,presence at design ng wheels ang nagta-transfer sa thrust force na yun.


i disagree that the thrust is being transferred to the wheels.
the propellers to be exact provide the thrust to move the plane forward.

but i agree with your answer, only if the question would state that the wheel is powered that's why i've mentioned the question is flawed. a real airplane wouldn't have a powered wheel.

so if we put it in this condition, yung wheel ng airplane ay powered (like that of a car) then naka-off yung propellers, lagay sa treadmill...doon malamang stationary nga ang airplane.

[Dax]

Okay... I have a side question... what if we have a plane taxiing down the treadmill/runway while the treadmill is off (in other words, same situation as on "solid ground"). And then suddenly, we turn on the treadmill (backwards in the opposite direction, to match the speed of the wheels, etc.). What would happen next? :confused:The plane would run on the conveyor belt's surface but would stay stationary relative to a fixed object. It won't be able to take off.

I think we need the toy below + a large conveyor belt...:D
86IP9UXIHBM

Addition: (in support of ninong's theory)
Source: Aviation History On-line Museum (http://www.aviation-history.com/theory/airfoil.htm)
http://www.aviation-history.com/theory/foil.gif
From the source above:
"Pressure is reduced is due to the smaller space the air has above the wing than below. Air cannot go through the wing, so it must push around it. The surface air molecules push between the wing and outer layers of air. Due to the bump of the airfoil, the space is smaller and the molecules must go faster. According to Bernoulli's Law, faster air has lower air pressure, and thus the high pressure beneath the wing pushes up to cause lift."

In more simpler words:
1. Ordinarily (stationary runway), as the plane runs forward, air flows both over and under the wing. Agree ba tayo lahat? :D
2. Ok, the air that moves both over and under the wing reach the wing tip at the same time. Meaning the air over the wing travels faster than the air under...(greater speed = greater distance/same time). Agree ba tayo ulit? :D
3. Therefore the air pressure over the wing is less than that under the wing, based on Bernoulli's Law as explained above. Agree? :D
4. Kaya nahihigop ang wing/plane pataas = this is how a plane flies.
5. Now...if the plane does not move relative to a stationary point, there will be no difference in air pressure between over and under the wing. Agree?
6. Hence, the plane won't fly. Q.E.D. ;)

[ninong]

i disagree that the thrust is being transferred to the wheels.


maybe na mis-interpret mo ako dahil malabo ang explanation ko o sa pag gamit ko sa word na''transfer'' sa aking explanation.
iibahin ko ang sentence ko pero same ang meaning na ibig kong sabihin.

ang thrust ng airplane ay nata-trasfer sa wheels---ibig sabihin ay nagmamaterialize ang forward move dahil meron syang wheels at sa pamamagitan ng mga wheels na ito.katulad din ng isang cart na itinutulak ng tao.yung tao ang thrust force at umuusad ang cart dahil sa mga gulong nito.yun po ang ibig kong sabihin.


In more simpler words:
1. Ordinarily (stationary runway), as the plane runs forward, air flows both over and under the wing. Agree ba tayo lahat?
2. Ok, the air that moves both over and under the wing reach the wing tip at the same time. Meaning the air over the wing travels faster than the air under...(greater speed = greater distance/same time). Agree ba tayo ulit?
3. Therefore the air pressure over the wing is less than that under the wing, based on Bernoulli's Law as explained above. Agree?
4. Kaya nahihigop ang wing/plane pataas = this is how a plane flies.
5. Now...if the plane does not move relative to a stationary point, there will be no difference in air pressure between over and under the wing. Agree?
6. Hence, the plane won't fly. Q.E.D.

heto ang detailed explanation.yung post ko sa itaas ay basic....same principle.

[liong]

nice one sir dax.... may video pa...:D parang top gun ah....:D

Di pa rin lilipad......:D

siguro ganito isipin natin.... aangat lang ang ating eroplano kapag....

1. may enough speed na maiiproduce ang eroplano.... in our case wala...kasi nga
na sa ibabaw siya ng massive conveyor which is same sila ng acceleration ng conveyor.
in that case na sa same location pa rin si eroplano.

2. may nag-act na force sa wings....dito ngayon natin ipapasok ang theory ng lift and drag
kung walang enough speed... saan kukuha ng lifting force nakokontra sa wings para umangat..? look at the illustration na example ni sir dax...

pagisipan ng mabuti...:D

[infinite_trial]

i'd still say it would fly :D

and i would repeat the question is flawed. unless the treadmill can track the speed of the airplane's wheels, then the plane would remain in its position.

image (http://uploader.ws/upload/200611/ITTAKESOFF.gif)

[andres]

Hmmmmmm...... base sa aking obserbasyon, agree tayong lahat sa lahat, EXCEPT sa isang maliit na detalye. Pero napaka-importanteng detalye!

Tinanong ko yung side question para mabawasan ang mga variables (acceleration from rest, etc., etc.).

Okay... I have a side question... what if we have a plane taxiing down the treadmill/runway while the treadmill is off (in other words, same situation as on "solid ground"). And then suddenly, we turn on the treadmill (backwards in the opposite direction, to match the speed of the wheels, etc.). What would happen next? :confused:

Ngayon ang Tanong: gagalaw ba? Gagalaw ba ang eroplano sa ibabaw nang treadmill na umiikot? (Huwag muna nating isipin kung "lilipad ba?")

Ayon sa Team Dekinai~yo! :D , the plane will remain stationary with respect to the ground, the surrounding air etc., etc. Kaya imposibleng lumipad ang plane (korek ba?)

Ayon naman sa Team Lilipad Tayo!, gagalaw pa rin ang eroplano sa ibabaw ng conveyor belt. Paano nangyari yon? Kasi nga -- kasi nga -- pasensya na talaga at paulit-ulit ako -- freewheeling ang mga gulong. In other words, walang pipigil sa pag-abante ng eroplano along the x-axis. Kasi nga freewheeling ang mga gulong.

At kung aabante ang plane along x, makalilipad ito.

Kaya hindi apt ang analogy ng running man sa eskalavator. Kasi sa running man, ang nagpapatakbo ay ang mga hakbang ng mga paa na directly connected to the ground.


~~~~~~~~~~~

Baka ganito mas ma-feel natin.

Kunwari ikaw si Wile E. Coyote. Bumili ka ng rollerblades mula sa Acme corporation. Tapos kinabitan mo ng Taepodong-2 ang iyong Acme helmet.

Kung meron tayong situation tulad ng nakasulat sa itaas, anong mangyayari? Gagalaw ka ba?

Paano makaka-apekto and pag-ikot ng treadmill sa pagbiyahe mo?

~~~~~~~~~~~

Mga ganitong klaseng usapan mas enjoy kapag may kasamang beer at pulutan :D :toast:

[Sacod]

sali ako sa usapan. hindi lilipad ang eroplano.

kahit nasa maximum speed na ang jet engine ng eroplano nasa stationary point pa rin ang eroplano.why?
because yung forward force ng eroplano dala ng jet engine yung din ang speed ng conveyor na pabalik.so ang mangyayari NO DISPLACEMENT at walang hangin na babanga( air friction) sa pakpak ng eroplano.so pa ikot-ikot na lang ang gulong ng eroplano hangang sa makatulog ang Piloto at maubusan ito ng fuel.

O.T.
siguro alam na natin kung paano pinapalipad ang isang F16 sa aircraft carrier..
sa nakikita natin yung distance ng runway is not normal, maiksi or malapit compara sa ordinary runway ng airport mahaba o long distance..
para sufficient yung force para maka take off.they have a special machine na tinatawag nila na SLINGSHOT
ito yung tutulak pa abante sa F16 sabay ng pwersa ng jet engine nito ,kaya ito nakakalipad kahit na malapitan...


my conclusion: kung walang hangin na babanga sa pakpak ng eroplano hindi ito lilipad..

TAGAY!!!:D
:toast:

[infinite_trial]

hehe uulitin ko lang yung sinabi ko na dati at nisabi na din ni andres.

masasatisfy lang ang "no displacement" situation kung imamatch ng conveyor ang speed ng gulong by speed monitoring. kasi nga hindi powered ang gulong ng eroplano so mangyayari everytime na iikot ang conveyor, nadodoble ang speed ng gulong. in that case, hindi nga lilipad...malamang sumabog lang ang gulong.

so i therefore conclude, walang tamang sagot hahahaha.

[Dax]

~~~~~~~~~~~

Baka ganito mas ma-feel natin.

Kunwari ikaw si Wile E. Coyote. Bumili ka ng rollerblades mula sa Acme corporation. Tapos kinabitan mo ng Taepodong-2 ang iyong Acme helmet.

Kung meron tayong situation tulad ng nakasulat sa itaas, anong mangyayari? Gagalaw ka ba?

Paano makaka-apekto and pag-ikot ng treadmill sa pagbiyahe mo?

~~~~~~~~~~~

Mga ganitong klaseng usapan mas enjoy kapag may kasamang beer at pulutan :D :toast:
Galing ng imagination mo andres. Mas madali nga maimagine kapag ganito ang example na gagamitin. Pwede din nating palitan ang threadmill ng "giant turn table", say 1km in radius. :D Ok nagi-skate si Wile E. Coyote clock-wise (as is normal for public rinks), umi-ekes na ang legs nya kasi pa-curve ang takbo sa rink. Mas lalong bumilis kasi biglang nag-boost ang Taepodong-2. Walang sinabi ang time ni Shimizu sa bilis. Tapos, biglang umandar ang turn table sa kabilang direksyon. Babagal ba, mananatili, o bibilis ang ikot ni Wile E. Coyote relative sa gitna ng rink (stationary)? I think babagal...hanggat mag kasing bilis na ang ikot ng rink sa ikot niya, kung saan magiging stationary na siya, with respect to the center...unless makita nya si Road Runner. :p
masasatisfy lang ang "no displacement" situation kung imamatch ng conveyor ang speed ng gulong by speed monitoring. kasi nga hindi powered ang gulong ng eroplano so mangyayari everytime na iikot ang conveyor, nadodoble ang speed ng gulong. in that case, hindi nga lilipad...malamang sumabog lang ang gulong.Hehe given na nga yan IT - kayang i-match ng conveyor belt ang speed ng gulong. Kung pano gagawin ito ay di na natin problema. :p

Kagabi pinilit kong mag-agree sa sinabi ni andres na "freewheeling ang mga gulong". Pero hindi talaga yata magiging free-wheeling kasi nga may bigat ang eroplano na dumidiin sa mga gulong pababa (causing friction). Magiging freewheeling kung halimbawa may cranes na nagsususpend sa eroplano - pero wala.

Subukan nyong gumawa ng FBD (free body diagram) ng plane, weight of plane, boost of jets, friction due to conveyor belt etc. Ang magiging resultant ng forces ay pointing downwards sa conveyor belt, at an angle siempre. Magiging free-wheeling lamang kung ang resultant ay:
1. pointing horizontally to the front
2. pointing upwards

Neither 1 nor 2 will happen because we cannot cancel out the plane's weight with the force of the boost.

[Sacod]

OT
dagdagan natin yung problema..


what if lagyan natin ng isang higanteng electric fan sa harap ng eroplano.kung anu yung speed ng jet engine ng eroplano ganun din yung speed ng ikot ng electric fan at speed ng conveyor.
anu sa tingin nyo?aangat ba yun eroplano?


haaaayyy lasing na yata ako,hehehe!!!!!!!!! :D

[andres]

Sige simulation tayo.
Sa aking interpretasyon kasi, may interesting na nangyayari sa bilis ng pag-ikot ng gulong.


Let:
v1 = plane's velocity
v2 = wheels' velocity
v3 = conveyor belt's velocity (opposite direction)


For simplicity, sabihin natin na merong aiplane traveling at constant velocity of 50 kph along a treadmill turned OFF.

At t=0,
v1 = 50 kph
It follows that
v2 = 50 kph
But v3 = 0 kph.

At t=1, we turn on the treadmill, which is designed to match the velocity of the plane's wheels (v2) in the opposite direction.
Since v2 = 50 kph,
v3 (target) = 50 kph.

At t=3, v3 reaches the target velocity of 50 kph.

At this point, we should consider 2 things:

(1) By definition, v2 = v1 + v3.
The speed of the wheels' spinning is equal to the speed of the plane plus the speed of the conveyor. Correct?

(2) Now the controversial part -- I maintain that v1 will not change. Since the plane's wheels are freewheeling the movement of the treadmill cannot prevent the plane's forward motion. The plane get its thrust from the suction of air through the jet/propeller (it's as if the plane were grabbing the air to propel itself forward).

So, again, at t=3:
v3 = 50 kph
v1 = 50 kph
v2 = 50 + 50 = 100 kph.

The mechanism senses this, so at t=3,
v3(target) = 100 kph.

And so on....
At t=4, v3 reaches its new target velocity
v3 = 100 kph
v1 = 50 kph
v2 = 100 + 50 = 150 kph

We see that this goes on and on.... the velocity of the wheels (and the treadmill) is constantly increasing, while the velocity of the plane is a steady 50 kph.

[Dax]

(1) By definition, v2 = v1 + v3.
The speed of the wheels' spinning is equal to the speed of the plane plus the speed of the conveyor. Correct?
I'm sorry andres but I cannot agree that v2 = v1 + v3, for all values of v3 other than 0. v1 should be equal to v2 at all times as long as the plane is intact. :D The wheels are fixed on the plane and threfore cannot move forward faster nor slower than the plane. I am talking in terms of linear motion, not angular by the way.

(2) Now the controversial part -- I maintain that v1 will not change. Since the plane's wheels are freewheeling the movement of the treadmill cannot prevent the plane's forward motion.
I don't agree with the "freewheeling" wheels as I explained in post #60:
Subukan nyong gumawa ng FBD (free body diagram) ng plane, weight of plane, boost of jets, friction due to conveyor belt etc. Ang magiging resultant ng forces ay pointing downwards sa conveyor belt, at an angle siempre. Magiging free-wheeling lamang kung ang resultant ay:
1. pointing horizontally to the front
2. pointing upwards

Neither 1 nor 2 will happen because we cannot cancel out the plane's weight with the force of the boost.

[infinite_trial]

still i'd say wheel resistance relative to the weight of the plane would have minimal effect... :D

f - thrust to move a plane
w - weight of the plane (newtons)
s - speed (meters/second)

f = ws --> eq.1

given:

plane = boeing 747

weight = 800,000lbs
1lb = 4.48 newtons
w = 3,584,000 newtons

takeoff speed = 180 miles/hr
1 mph = 0.447 mps
s = 80.46 mps

f = ws
f = (3,584,000 N)(80.46 mps)
f = 288,368,640 joules/s

rr - rolling resistance (plane's wheel)
w - weight of the plane (newtons)
ar - actual wheel resistance
s1 - speed of plane (meters/second)
s2 - speed of the conveyor

given:

no. of wheels = 16 main wheels + 2 nose wheels*
ar = 1.16 (assuming rubber on rubber)

rr = (w/no. of wheels)(ar)(s1 - s2)
(s1 - s2) - since they are opposing forces
rr = (3,584,000 N/18) (1.16) (80.46 mps - 80.46mps)
rr = 230,968.889 joules/s

f > rr

288,368,640 joules/s > 230,968.889 joules/s
actual thrust force = f - rr
actual thrust force = 288,368,640 - 230,968.889 joules/s
actual thrust force = 288,137,671.111
therefore the airplane would move forward

sensya na kung may mali mang unit..limots ko na

*i forgot to link a site, it says the nose wheels carry the weight of the plane while the main wheels would be free-rolling/free-wheeling.

[andres]

Wow infinite!

Pero teka... hindi kaya may konting mali...

rr = (3,584,000 N/18) (1.16) (80.46 mps - 80.46mps)
rr = 230,968.889 joules/s



Your velocities cancel each other out. Anything multiplied by zero is zero. No rr?

[reon]

Hindi pa ba lumilipad yang eroplano na yan?! :)

(Sige ituloy lang ninyo ang discussion at nakakaaliw basahin.)

[infinite_trial]

Wow infinite!

Pero teka... hindi kaya may konting mali...



Your velocities cancel each other out. Anything multiplied by zero is zero. No rr?

haha oo nga noh tangeks :D

i made a big boo boo hahahaha

pero reresearch ko pa yung calculation ng opposing forces kasi yung original na formula nung rr wala namang s2...siningit ko lang.

[ninong]

basta ako,yung eroplanonmg sasakyan :D :D :D ko pauwi sa pinas bukas ay lilipad kasi walang conveyor sa runway...:D :D :D

[ninong]

Hehe given na nga yan IT - kayang i-match ng conveyor belt ang speed ng gulong. Kung pano gagawin ito ay di na natin problema. :p

Kagabi pinilit kong mag-agree sa sinabi ni andres na "freewheeling ang mga gulong". Pero hindi talaga yata magiging free-wheeling kasi nga may bigat ang eroplano na dumidiin sa mga gulong pababa (causing friction). Magiging freewheeling kung halimbawa may cranes na nagsususpend sa eroplano - pero wala.

Subukan nyong gumawa ng FBD (free body diagram) ng plane, weight of plane, boost of jets, friction due to conveyor belt etc. Ang magiging resultant ng forces ay pointing downwards sa conveyor belt, at an angle siempre. Magiging free-wheeling lamang kung ang resultant ay:
1. pointing horizontally to the front
2. pointing upwards

Neither 1 nor 2 will happen because we cannot cancel out the plane's weight with the force of the boost.

tumbok na tumbok mo ang ibig kong sabihin sa mga posts ko pareng dax.

[liong]

basta ako,yung eroplanonmg sasakyan :D :D :D ko pauwi sa pinas bukas ay lilipad kasi walang conveyor sa runway...:D :D :D

ninong pauwi ka pala!!:D buti nalang nga nakakalipad:D kapag may time ka...tanong mo na rin sa mga piloto kung ano ba talaga ang sagot...baka alam nila..:D

@IT...galing may computation pa...ang chulit....hihihihi:p sige maghahalungkat ako sa baul ng computation din.....:p pero batay sa computation mo di lilipad........:p

mukhang aabot pa ata ito sa inuman ah.......:D

[infinite_trial]

ninong pauwi ka pala!!:D buti nalang nga nakakalipad:D kapag may time ka...tanong mo na rin sa mga piloto kung ano ba talaga ang sagot...baka alam nila..:D

@IT...galing may computation pa...ang chulit....hihihihi:p sige maghahalungkat ako sa baul ng computation din.....:p pero batay sa computation mo di lilipad........:p

mukhang aabot pa ata ito sa inuman ah.......:D

anong di lilipad..lilipad kahit nagkamali ako ng compute! :p
nawala nga yung friction e...:D

[liong]

anong di lilipad..lilipad kahit nagkamali ako ng compute! :p
nawala nga yung friction e...:D

post mo naman yung link o..para ating siyasatin ng husto....:p nawawala yung mga orasyon ko eh....:D

[infinite_trial]

post mo naman yung link o..para ating siyasatin ng husto....:p nawawala yung mga orasyon ko eh....:D

nampoots e hiwalay hiwalay nga yon hahaha!!!
nasa office yung search history ko e :p

maghanap ka ng formula mo! disprove me!! hahaha!!! :D:p

sorry ot po.

[simor_buts]

OT
what if lagyan natin ng isang higanteng electric fan sa harap ng eroplano.kung anu yung speed ng jet engine ng eroplano ganun din yung speed ng ikot ng electric fan at speed ng conveyor.
anu sa tingin nyo?aangat ba yun eroplano?

haaaayyy lasing na yata ako,hehehe!!!!!!!!! :D

alak pa nga dyan!!!!:D tingin ko prof lilipad... ganyan kasi ang concept ng windtunnel experiment or testing (whatever!!!). tama ba?;)

is it worthy to discuss kung makakarating from point 1 to point 2 ang plane bago natin pag-usapan kung lilipad ang plane? tanong lang po....

EB na 'to: 'The Mystery of Plane and Treadmill Grand Conference For Good and Bad and Make Benifit of Timog Forum'

[Stacie Fil]

Ang daming EB fever ngayon ah! Epekto siguro nang paglamig nang panahon. Well, can't blame, masarap talaga ang may ka huntaan.:D

Its been awhile since my last visit at this thread, ang haba na at ang saya nang discussion. Ang galing!

Going back to the original question; (Imagine a plane is sitting on a massive conveyor belt, as wide and as long as a runway, and intends to take off. The conveyer belt is designed to exactly match the speed of the wheels at any given time, moving in the opposite direction of rotation. Can the plane take off?)

Its really hard to imagine a boeing 747 taking a lift from a running conveyor. Im not saying either thats its impossible or possible, (for the sake of theory or for the fact that it is not yet being done in actual practice.)

Whats playing in my head are only a possibilities and what if's. What if we are dealing with a smaller craft but powerful propulsion? How about putting a wheel on a missile and placing it to similar condition as the plane?

Will it not just go over the capacity of the spinning tire in contact with the ground/conveyor and speed overcome the other variables and fly off?

Just imagine if this are possible. A shorter place for flight and landing of plane.:D


:)

[ninong]

Whats playing in my head are only a possibilities and what if's. What if we are dealing with a smaller craft but powerful propulsion? How about putting a wheel on a missile and placing it to similar condition as the plane?

Will it not just go over the capacity of the spinning tire in contact with the ground/conveyor and speed overcome the other variables and fly off?

Just imagine if this are possible. A shorter place for flight and landing of plane.:D


:)

medyo may kahirapan na gawin kahit sa mini scale lang sir dahil sa condition na,dapat ima-match ng conveyor ang speed ng wheels.dito kasi kailangan ang accurate na computer program at iba pang materials para ma satisfy ang condition na yun.

[NemoySpruce]

Pinaka magandang paraan para ma test is to use a computer simulation, add all factors. Crucial to the experiment is the treadmill matching the speed of the wheels at all times. Palagay ko, If this condition is met, the plane will not move forward. Speed relative to the ground will be at zero. However 'lift' is a separate argument. Since the treadmill is as long and wide as a normal airstrip, it is possible that it will generate aircurrents that will provide enough lift for the plane to take off, the wheels will lose contact with the treadmill and the plane will move forward.IF there is enough lift, then the plane can generate enough ground speed to take off properly, if not enough lift the plane will not fly for long, when the plane leaves the aircurrent generated by the treadmill, it will 'stall' and crash. ayun sa aking hakahaka....hehehe.

medyo may kahirapan na gawin kahit sa mini scale lang sir dahil sa condition na,dapat ima-match ng conveyor ang speed ng wheels.dito kasi kailangan ang accurate na computer program at iba pang materials para ma satisfy ang condition na yun.

[infinite_trial]

Pinaka magandang paraan para ma test is to use a computer simulation, add all factors.

i'm willing to make a program out of it if we could agree on the formula to be used :)

[NemoySpruce]

abaaa. maganda yang idea mo ah. sige i will try to come up with the formula. Pero Math one lang ako nung kollehiyo eh, so kung may mga engineers/physicists etc.. jan, please contribute :D



i'm willing to make a program out of it if we could agree on the formula to be used :)

[infinite_trial]

abaaa. maganda yang idea mo ah. sige i will try to come up with the formula. Pero Math one lang ako nung kollehiyo eh, so kung may mga engineers/physicists etc.. jan, please contribute :D

well we should all agree on the factors that would be involved.
i posted a formula before but that only involves thrust and rolling friction. so if we give all the conditions (lift, drag, weight, thrust), this would be complicated. masyadong may pagkapiloto na ang dating :D

i'll try my best. what's on my mind is to use flash with actionscripting para macontrol yung exact movements ng ating model airplane. pahirapan nga lang ito...malamang matagal gawin. pero sabi ko nga try ko kapag may formula at mag-agree tayo lahat sa mga set conditions.

[NemoySpruce]

hehehe. ok yan infini, tulungan kita mag script at graphics. I think there would be a lot of people interested in it if we could do it. baka sumikat tayo all over the internet!! kasi sa ibang threads, mga aero engineers daw nag po-post at nanghuhula din, di alam kung lilipad ang eroplane. hehehe. sir Nick, pwede ba kaming balato pag lumaki ang income nyo sa adsense...wahehe, baka sakali.

tingin ko basic factors/variables should be,

speed of plane relative to ground in kph
airspeed of plane in kph
rev of wheels in rpms
speed of treadmill surface in kph
weight of plane in kilos

Force of thrust in Newtons
Force of lift in Newtons
Force of drag in Newtons

Headwind speed in kph


....anu pa ba?


well we should all agree on the factors that would be involved.
i posted a formula before but that only involves thrust and rolling friction. so if we give all the conditions (lift, drag, weight, thrust), this would be complicated. masyadong may pagkapiloto na ang dating :D

i'll try my best. what's on my mind is to use flash with actionscripting para macontrol yung exact movements ng ating model airplane. pahirapan nga lang ito...malamang matagal gawin. pero sabi ko nga try ko kapag may formula at mag-agree tayo lahat sa mga set conditions.

[infinite_trial]

hehehe. ok yan infini, tulungan kita mag script at graphics. I think there would be a lot of people interested in it if we could do it. baka sumikat tayo all over the internet!! kasi sa ibang threads, mga aero engineers daw nag po-post at nanghuhula din, di alam kung lilipad ang eroplane. hehehe. sir Nick, pwede ba kaming balato pag lumaki ang income nyo sa adsense...wahehe, baka sakali.

tingin ko basic factors/variables should be,

speed of plane relative to ground in kph
airspeed of plane in kph
rev of wheels in rpms
speed of treadmill surface in kph
weight of plane in kilos

Force of thrust in Newtons
Force of lift in Newtons
Force of drag in Newtons

Headwind speed in kph


....anu pa ba?

madaling magbigay ng mga variables if alam na natin ang formula.
dapat ba nating iconsider ang initial speed or takeoff speed lang?
kasinghaba ba ng typical runway yung treadmill?
kung icoconsider ang friction dapat malaman din yung material ng treadmill.
saka yung main na pinagtatalunan natin is yung mechanism ng wheels and kung positive or negative ang effect ng opposite motion ng treadmill.

hehe bigla naman ako napressure sa sinabi mong adsense. kailangan pacheck ang coding at calculation hehehe.

binabasa ko nga yung NASA (http://www.grc.nasa.gov/WWW/K-12/airplane/forces.html) saka dito (http://www.av8n.com/how/htm/4forces.html#fig-drag-venn).

[NemoySpruce]

Susmaryosep! komplikado pala ano. simplehan na lang natin para di na tayo pipili ng materials etc.. gawin na lang natin adjustable ang friction. Pati yung wing type adjustable din. so pwede adjust ng user kung gusto nya how much lift the wings will generate, tapos saka na lang natin research kung ano ang standard values. Length ng treadmill is typical runway, para may limit, if the plane cannot take off within that eh di hindi talaga pede. The more the merrier so kung sino man gusto maki gulo, tayo na at magpalipad ng eroplano!




madaling magbigay ng mga variables if alam na natin ang formula.
dapat ba nating iconsider ang initial speed or takeoff speed lang?
kasinghaba ba ng typical runway yung treadmill?
kung icoconsider ang friction dapat malaman din yung material ng treadmill.
saka yung main na pinagtatalunan natin is yung mechanism ng wheels and kung positive or negative ang effect ng opposite motion ng treadmill.

hehe bigla naman ako napressure sa sinabi mong adsense. kailangan pacheck ang coding at calculation hehehe.

binabasa ko nga yung NASA (http://www.grc.nasa.gov/WWW/K-12/airplane/forces.html) saka dito (http://www.av8n.com/how/htm/4forces.html#fig-drag-venn).

[infinite_trial]

Susmaryosep! komplikado pala ano. simplehan na lang natin para di na tayo pipili ng materials etc.. gawin na lang natin adjustable ang friction. Pati yung wing type adjustable din. so pwede adjust ng user kung gusto nya how much lift the wings will generate, tapos saka na lang natin research kung ano ang standard values. Length ng treadmill is typical runway, para may limit, if the plane cannot take off within that eh di hindi talaga pede. The more the merrier so kung sino man gusto maki gulo, tayo na at magpalipad ng eroplano!

how bout step by step analysis?
pagtalunan muna kung uusad ang eroplano :D

anyway, additional site (http://www.auf.asn.au/groundschool/umodule11.html) for our study :D

http://www.auf.asn.au/groundschool/todistance.jpg

and pdf (http://www.google.com/url?sa=t&ct=res&cd=6&url=http%3A%2F%2Fwww .dfrc.nasa.gov%2FEdu cation%2FOnlineEd%2F NewtonsLaws%2Fpdf%2F studtakeoff.pdf&ei=GaCLRcvWF4OusALto PGQDw&usg=__65KKfPSze6B0c2 BeVvrDGK9s2kk=&sig2=h9_u_amzhTpX1F7 070_aNw)for some formulas

[andres]

EB na 'to: 'The Mystery of Plane and Treadmill Grand Conference For Good and Bad and Make Benifit of Timog Forum'

Hahahahahahaa!!! :roll:

[andres]

I'm sorry andres but I cannot agree that v2 = v1 + v3, for all values of v3 other than 0. v1 should be equal to v2 at all times as long as the plane is intact. :D The wheels are fixed on the plane and threfore cannot move forward faster nor slower than the plane. I am talking in terms of linear motion, not angular by the way.


Duuuuuuuuuuuuuuuuuud e......

I think v2 = v1 + v3 is always true*
(*on condition that the wheels do not skid)
Now let me try to prove that :)


Let's say I have a toy car ("matchbox" type). Let's say we have a treadmill (like for doing exercise on).

Let:
v1 = vehicle's velocity
v2 = vehicle's wheels' velocity
v3 = conveyor belt's velocity (opposite direction)

case 1:
I hold the toy and roll it along the ground at 10 kph.
v2 = v1 + v3 = 10 + 0 = 10 kph.

case 2:
I hold the toy stationary on top of a treadmill which is running "backwards" with respect to the toy at 10 kph.
v2 = v1 + v3 = 0 + 10 = 10 kph.

case 3:
I move the toy forward at 10 kph on top of a treadmill which is running "backwards" at 10 kph.
v2 = v1 + v3 = 10 + 10 = 20 kph.

case 4:
I move the toy forwards at 10 kph on top of a treadmill which is also running "forward" at 10 kph.
v2 = v1 + v3 = 10 + -10 = 0 kph.

I cannot see how one can argue with this.
Case 1 and case 2 are obvious. In case 3, the toy is moving at 10 kph with respect to the ground, but since the treadmill is moving in the opposite direction at 10 kph, the wheels spin twice as fast, at 20 kph. In case 4, we essentially move the toy in time with the moving treadmill, and thus the wheels do not turn. You can try it at home! :D

I think that unless we can agree about this, we cannot have a productive discussion about whether our plane will fly or not. ;)

[infinite_trial]

^ may nakita nga akong experiment electric fan sa ibabaw ng skateboard pero hindi sa ibabaw ng treadmill.

[ninong]

Let:
v1 = vehicle's velocity
v2 = vehicle's wheels' velocity
v3 = conveyor belt's velocity (opposite direction)




v1=v2 kaya (v1 or v2 )+ (-v3)=0
v1 is and will always be uqual to v2.syempre,magkadugt ong yan kaya magkapareho ang bilis.iba ba ang speed ng torso ng tao kesa sa speed ng paa kapag tumatakbo ang tao ?:D

also,curious ko lang itanong...
is there such thing as wheel velocity?di ko yata napapansin sa mga physics problems ang term na yun.wheel rev or wheel rotation ay madalas.kasi pag wheel velocity ay parang imagination ko ay naka break ang wheels at kaladkad ng sasakyan.

[andres]

v1=v2 kaya (v1 or v2 )+ (-v3)=0
v1 is and will always be uqual to v2.syempre,magkadugt ong yan kaya magkapareho ang bilis.iba ba ang speed ng torso ng tao kesa sa speed ng paa kapag tumatakbo ang tao ?:D

Oh come on. ...how then do you explain case #2 above? v1 is obviously not necessarily equal to v2.

[infinite_trial]

v1=v2 kaya (v1 or v2 )+ (-v3)=0
v1 is and will always be uqual to v2.syempre,magkadugt ong yan kaya magkapareho ang bilis.iba ba ang speed ng torso ng tao kesa sa speed ng paa kapag tumatakbo ang tao ?:D

kaya nga hindi pwedeng icompare yung eroplano sa tao (kahit sa kotse), kasi sa outside observer, yung speed ng wheels lets say 100 knots...pero yung speed ng eroplano relative to air is only 50 knots.

[andres]

also,curious ko lang itanong...
is there such thing as wheel velocity?di ko yata napapansin sa mga physics problems ang term na yun.wheel rev or wheel rotation ay madalas.kasi pag wheel velocity ay parang imagination ko ay naka break ang wheels at kaladkad ng sasakyan.

Ok let me clarify, by velocity of the wheels, I mean the angular velocity. Sorry about the confusion.

[Dax]

I think that unless we can agree about this, we cannot have a productive discussion about whether our plane will fly or not. ;)Dude, ang pagkakaintindi ko sa original proposition ay linear motion, hindi angular. Dyan tayo hindi magkasundo, for you it's angular/rotational speed of the wheels, for me it's linear (paabante lang). So there, I agree that we can't agree. :D

[andres]

Dude, ang pagkakaintindi ko sa original proposition ay linear motion, hindi angular. Dyan tayo hindi magkasundo, for you it's angular/rotational speed of the wheels, for me it's linear (paabante lang). So there, I agree that we can't agree. :D

There you go!

[ninong]

kaya nga hindi pwedeng icompare yung eroplano sa tao (kahit sa kotse), kasi sa outside observer, yung speed ng wheels lets say 100 knots...pero yung speed ng eroplano relative to air is only 50 knots.

kinowt ko ang post ni andress...di naman eroplano ang ginamit na sample sa mga cases ni andres.toycars daw.pwedeng i-compare ang speed ng tao sa toycar.



btw,meron ibang forum na ganyan din ang usapan....check it out.
http://forum.physorg.com/index.php?showtopic= 2417&st=0
http://www.boingboing.net/2006/12/11/airplanetreadmill_pr .html

[Dax]

There you go!But...I already cleared that in my post #63. :D
I'm sorry andres but I cannot agree that v2 = v1 + v3, for all values of v3 other than 0. v1 should be equal to v2 at all times as long as the plane is intact. :D The wheels are fixed on the plane and threfore cannot move forward faster nor slower than the plane. I am talking in terms of linear motion, not angular by the way.
@ninong,

Sa ibang forums di rin sila magkasundo. :biglaugh:

[andres]

But...I already cleared that in my post #63. :D



There you go! I missed that one HAHA! Alam mo ba malapit na akong umiyak! Hindi tayo magkaintindihan :D

Now the question is.... was the original question referring to linear velocity or angular velocity?

I would argue that "speed of the wheels" refers to angular velocity. If it was referring to linear velocity, wouldn't the question just have said "speed of the plane"??

[ninong]

guys,meron bang SI conversion ang rad/s sa kph?

[Stacie Fil]

guys,meron bang SI conversion ang rad/s sa kph?


Engot na talaga ako, this was long time ago for me. Let me try anyway.

I may be wrong but in rad or deg, I think,you are considering rotation in a circular plane by unit in angular velocity/rotaion. You must know the radius or dia(of the wheel where the conveyor attached/rotates) to get the circumference, and later convert the unit to SI or in km as you wish/hour.

:)

[infinite_trial]

guys,meron bang SI conversion ang rad/s sa kph?

wala yata...rev/min meron.

1 rev/min (rpm) = 0.1047 rad/s

[Dax]

Alam mo ba malapit na akong umiyak! Hindi tayo magkaintindihan :D Nagkakaintindihan tayo andres, hindi lang magkasunduan. :D
Now the question is.... was the original question referring to linear velocity or angular velocity?

I would argue that "speed of the wheels" refers to angular velocity. If it was referring to linear velocity, wouldn't the question just have said "speed of the plane"??Original: "The conveyer belt is designed to exactly match the speed of the wheels at any given time, moving in the opposite direction of rotation."

Ganito ang sitwasyon:

The conveyor belt is moving : -->
The wheels are moving in the opposite direction : <--

Bale ini-stress ng salitang "moving" ang linear motion. Hmm, you don't buy that do you? :p Kung angular dapat sana sinabi explicitly sa proposition, say "rolling in the opposite direction", "rotating in the opposite direction" and so on. Kaya ang pagkakaintindi ko ay linear talaga. :)

[ninong]

wala yata...rev/min meron.

1 rev/min (rpm) = 0.1047 rad/s

kung ganoon,di acceptable ang theory ni andres na v2(rad/m)= v1(kph) +v3(kph) dahil magkaiba ng unit. kung angular velocity ang v2,bakit kph ang unit ni andres sa v2 nya?dapat rad/m or rad/s di ba?paki explain pls,sir andress.

[infinite_trial]

nalimutan na yata etong thread na to hehe...

waiting pa din magpalipad ng eroplano :)

[ninong]

bakit kaya?busy siguro ang mga engrs or pagod pa sa holidays.