Psychics Puzzle

[Blasphemous]

What a brilliant question !!! It's had me wracking my brain all night, I think my brain will blow................ a bit like the OP's question blows

And your answer iiiisssss........?

 

[r.bartlett]

A Harrier jump jet will take off alright

 

[MarkBarl]

Of course it will. The forward acceleration of the plane is not driven through the wheels but rather the thrust of the engines.. The wheels just turn as the plane moves forward. Once the friction of the bearings in the wheels has been overcome the plane will continue to move forward. The conveyor will never be able to match the speed of the wheels. not because it couldn't go that fast, but because the forward movement is supplied by the thrust not driven through the wheels.

 

[Blasphemous]

Of course it will. The forward acceleration of the plane is not driven through the wheels but rather the thrust of the engines.. The wheels just turn as the plane moves forward. Once the friction of the bearings in the wheels has been overcome the plane will continue to move forward. The conveyor will never be able to match the speed of the wheels. not because it couldn't go that fast, but because the forward movement is supplied by the thrust not driven through the wheels.

Yeah... read the thread, I've answered it.

 

[blondini]

Will the plane ever take off?

Does the conveyor have paranormal powers?

 

[Trazor]

Of course it will. The forward acceleration of the plane is not driven through the wheels but rather the thrust of the engines.. The wheels just turn as the plane moves forward. Once the friction of the bearings in the wheels has been overcome the plane will continue to move forward. The conveyor will never be able to match the speed of the wheels. not because it couldn't go that fast, but because the forward movement is supplied by the thrust not driven through the wheels.

Yeah... read the thread, I've answered it.

Nearly, but you are both wrong.

 

[mattylad]

I thought that planes flew by air passing over/under the wings, how does the air do that when it is for all intents stood still?

 

[IJWS15]

Because it does not matter what the conveyor does - Try it with a child's toy and a piece of paper, it does not matter how fast you pull the piece of paper backwards pushing the plane forwards with your finger (as the engine thrust applied to the air surrounding the plane does, will cause the plane to move foprwards.

Now which way does the original post say the belt will move???


With a normal road car the answer would be different (rolling road) but not with a jet/rocket car like Thrust or Thrust SST.

 

[Blasphemous]

Of course it will. The forward acceleration of the plane is not driven through the wheels but rather the thrust of the engines.. The wheels just turn as the plane moves forward. Once the friction of the bearings in the wheels has been overcome the plane will continue to move forward. The conveyor will never be able to match the speed of the wheels. not because it couldn't go that fast, but because the forward movement is supplied by the thrust not driven through the wheels.

Yeah... read the thread, I've answered it.

Nearly, but you are both wrong.

Really? Oh well, come on then Einstein, give us the benefit of your wisdom on this. I cannot wait to hear you embarrass yourself. Begin....

 

[blondini]

Don't think this one's been posted here before.

An aircraft is standing on a very long runway that can move (a conveyor belt). The aircraft moves in one direction, while the conveyor belt moves in the opposite direction. This conveyor belt has a control system that tracks the aircraft's wheels' speed and tunes the speed of the conveyor belt to be exactly the same as the wheels, but in the opposite direction. There is no wind. The pilot begins to add thrust to the engines...

Will the plane ever take off?

I say no.

Its a bad question to start with as the conveyor and the aircraft wheels cannot go at the same speed.

Really! And why would that be then?

As soon as the plane moves forward relative to the conveyor, it's wheel speed will be greater than the conveyor speed. The conveyor cannot match the wheel speed once the plane is moving.

That's not why I say no.

 

[Blasphemous]

Don't think this one's been posted here before.

An aircraft is standing on a very long runway that can move (a conveyor belt). The aircraft moves in one direction, while the conveyor belt moves in the opposite direction. This conveyor belt has a control system that tracks the aircraft's wheels' speed and tunes the speed of the conveyor belt to be exactly the same as the wheels, but in the opposite direction. There is no wind. The pilot begins to add thrust to the engines...

Will the plane ever take off?

I say no.

Its a bad question to start with as the conveyor and the aircraft wheels cannot go at the same speed.

Really! And why would that be then?

As soon as the plane moves forward relative to the conveyor, it's wheel speed will be greater than the conveyor speed. The conveyor cannot match the wheel speed once the plane is moving.

That's not why I say no.

errr ok? So why do you say no then?

And I see trazor Einstein ain't been back on with his pearls of wisdom.

 

[crockett]

Are you guys seriously taking the p!5s ???!!!!! Leave it out.......

 

[Trazor]

Really? Oh well, come on then Einstein, give us the benefit of your wisdom on this. I cannot wait to hear you embarrass yourself. Begin....

What an arrogant reply from some one who does not fully understand the question or the forces involved.

I will give you my reasoning of the problem as follows...

Firstly to those who believe ( not you ) that the plane will not move, because the conveyor prevents forward movement, remember this.
The conveyor responds to wheel movement, wheel movement is caused by forward movement of the plane, so the only way the conveyor can ever move is if the plane moves FORWARD.
If the plane ever stops, so must the conveyor.

Whether the plane will take, off needs to be considered in 2 ways, theoretical or in practice

As a theoretical problem only, the plane will have no problem in taking off, as Newtons third law of motion ( As you said ) is all you need to understand.

Practically it's a different matter altogether.
And for this debate lets imagine that such a conveyor could be built.

The pilot now applies thrust and the plane moves forward, the conveyor now responds and moves in the opposite direction, as the plane increases speed so does the conveyor.
Now is the moment to look at this part of the question......."and tunes the speed of the conveyor belt to be exactly the same as the wheels"

"Tunes the speed" means a response time.
If the response time is instantaneous, then the wheels will be destroyed, well before take off.
At some point when the response time is long enough the plane will take off, as the conveyor is always playing catch up.

So their are 2 answersdepending on which view you take.

The You tube video although interesting, was not a direct comparison, as the wheels were always in contact with the runway, through the tarpaulin.

I would only embarrass myself, if I insulted anyone who disagrees with me.....

 

[breezer]

they did it on mythbusters, first a real conveyorbelt and a rc plane then a real plane and a very long sheet of paper stuff, in both cases the plane took off

 

[crockett]

So what supports a conveyor along its length when in operation ?? Or does it just sag in the middle?? It is normally supported by rollers, or a length of wood, metal, etc. So whether a length of tarpaulin has a hard surface under it, such as a runway, makes no difference to anything.

Jeez, the plane will take off. Just let this one be put to bed now.