I continue to be amazed at the folks who just don't get it.

You see...this is a bit of a trick question and whoever came up with it threw a big distraction into the riddle so that the answer wouldn't be so obvious. That distraction is the jet engine.

Because the jet engine doesn't push against the ground but against the air, it seems logical to think that the conveyor belt could not possibly have any affect on the movement of the plane. However, the reality is that the airplane on the conveyor would act no differently than a car on the conveyor. Even though the force required to move the plane is applied differently than the force required to move a car, the conveyor belt STILL applies an equal and opposite force against the plane due to the friction in the wheels and the fact that it ALWAYS matches the wheel speed.

Like I said, the jet engine is the "trick" in this riddle...and the majority of you are falling for it.

Simple physics folks...simple physics.

 

Hoss, can a Plane take off with all its wheels locked? because of how a jet engine works. the only way the wheel speed will stay the same is if the wheel speed and belt speed are 0 units... it is simply impossible for the wheels to turn on a jet airplane and not move. And since it was only stated the there is no Wind and not no air as long as the wheel speed remains at 0 units. That plane can move in relation to a stationary object. Since nothing was stated about traction that is ok.

Hoss is correct. That the plane cannot take off or even move if traction is held at 100%

In the real world a plane on a conveyor belt moving any speed would take off.
the Qustion at hand is illogical and impossable to awnser.

 

AMEN HOSS, simple physics!!!

 

Likewise here.

THE PLANE WILL FLY!!

The reason a car couldnt/wouldnt move on the conveyor is because it is propelled by the wheels, and the conveyor matches the speed of the wheels. Well; the plane is NOT driven from the wheels. The wheels have NO effect on the plane taking off. They just spin.

For those who think it wont fly:

Let me ask it to you this way. What if you make the wheels on the plane HALF the size they are now, and put it on a normal runway. They will spin twice as fast as they would normally, so it would be just like being on the converyor, right(wheels spinning twice as fast)? You still think it wont take off?? Thats why they have bearings in them,and not crappy bushings. So they can spin free!

Im interested to see how you guys can explain that one...

Eric

 

The faster the belt goes the less friction between the tire and belt . Since no pacific aircraft was mentioned I would have one that had enough power to compensate for what little drag would be left . It would be like water skiing bare foot the belt would moving fast enough their would be very little contact with it. We have all seen race cars take off and speed boats when high speed is involved Simple physics folks...simple physics. It would fly with very few changes to the aircraft if any .You are way over thinking the drag of those little tires it would not be that much .Plus the pilot could reduce a great deal by just pulling back on the stick . Aircraft tires have very little traction .

 

The intelligence or lack there of in this forum is humors, to say the least. Its frustrates me that some of you lack the capacity to fully comprehend the Varity of Variables left it the equation.

Justin

 

OK, after following this throught 457 posts, I just have one question.... Does the wing of an aircraft derive lift directly from the air moved by the engine? If so, the plane will fly. If the lift is provided by the plane moving forward through the air, proppelled forward by the thrust of the engine, then the plane will not fly.....


this whole thing has become

geico , bet yer laughin yer you-know-what off.........

 

The air moved by the jet engine has nothing to do with lifting the wings. It is due to the air the plane drives through going over the curved topside of the wing. It makes a vacuum that lifts the plane. Bernoulli's Law (I think that is which one it is).

The jet engine compresses massive amounts of air that pushes against the static air behind the plane and makes it go. Also quite a bit of vacuum in front (just ask the many people who have been sucked into the jet). This is what actually MOVES the plane ... not the wheels.

Look at the bush planes in Alaska ..... no wheels on them but they still move even on hard snow pack (with the ski's). The props do the same thing as the jets just in a different way.

PISTOL

 

The size of the wheel doesn't matter. The condition was that the conveyor speed ALWAYS matches the wheel speed. The result of that condition is that no matter how fast the plane tries to go, the conveyor will always match the speed at which it is trying to roll along, but in the opposite direction. Two equal and opposite forces mean one thing....STATIONARY OBJECT.

Not only will the plane not take off, but it will never even MOVE.

You folks who think it will fly need to start thinking outside of the box. The seemingly logical and obvious answer to this riddle is not the correct answer. It's a trick question.

John, that's the second argument you've tried that doesn't hold water. Come on now...I know you're smarter than this. Don't let the trick get the best of you.

HA!!! The irony!!!

 

In the real world that would be one BHCB (Big Honkin Conveyor Belt) Only hoss the designer of the concrete bed liner would come up with something like that (that was you, right hoss)

Same thing with the a man in the woods, if a tree falls on him does he make a sound. Of course (CRUNCH!!!!)

 

i guess you didn’t understand that i said you where right. just not for the reason you think you are. only if traction is 100%
If the belt and wheels are forced to be the same speed in opposite not only will the plane not move but the wheels will not spin. that is because in no way is energy from the engine put towards spinning the tires. only towards forward motion and since no forward motion can be achieved while the belt and wheel are in perfect opposite, the wheels CANOUT start spinning.
If u don’t understand what im saying you have some serious problems with understanding energy transfer. Energy cannot be made or destroyed. It is transferred. In order for the wheels to spin and not have the plane move forward energy would have to be MADE. Simple Physics Guys… but the plain can take off. If the wheels and belt are both 0mph, the only number u can divide 0 by is 0

PS. im getting payed to write this stuff i hope the Rest of you arnt waisting your free time in here.

 

It would take off, and make the mechanics happy too because the wheel bearings wouldnt have any wear!

 

I didn't realize you were agreeing with me. You're all running together now!!!

That being said, I think you misunderstood the intent of the riddle. The wheels and the conveyor are spinning in OPPOSITE directions. In other words, if the wheels are turning clockwise then the conveyor belt is turning counter-clockwise. Both the wheels and the conveyor are spinning....and of course there is no wheel slip (and there doesn't need to be since the wheels are just rolling on the conveyor belt).

 

it doesnnt say the wheels are spinning at the start. that has no affect. the wheel speed cannot change.
IT is 100% imposable for the belt to keep 100% traction and maintain exact opposite speeds if the plane moves in relation to a stationary object. There fore either the plane cannot move or traction must be lost.

Justin

 

Ok, here is another situation.
You have a trike( a 3 wheel motorcycle). the rear wheels are the powered wheels(just like the engines on the plane). there is a conveyer just wide enough to fit the single front wheel on and said conveyer matches the speed of the trike. If the rear wheels are on a solid surface and provide propulsion, and the front wheel rides on a conveyer that matches the speed of the trike in the opposite direction, will the trike move. YES! because the engine/drive wheels are not working in direct relation to the conveyer. If the front wheel was the drive wheel, it would just sit there and spin.