Physics Puzzle

[tim west]

If you mark a cross under the toy, when it gets to the checkout it will not have moved. even if you throw the box away, to get back to the end of the conveyor, it will need more speed than that of the conveyor belt

if the wheels were broken or had brakes and didnt turn then it wouldnt move off your cross, but it will have moved in space

The surface is moving, the plane is in the same spot all the time.

how can that be when a normal(not VTOL)aircraft needs airflow over its wings to take off and the plane in the video did indeed take off, if it hadnt moved from the spot as you say where did it get the lift from?

 

[doitall]

Dont think this ones 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 aircrafts 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?

[quote="balski" You have taken the OP's question and re-arranged it completely out of context.
Just reading through this jumble I have seen that Spacecat has given a good explanation .
Though being a physicist he ought to. icon_wink.gif

What are your credentials diyitall on the subject ? [/quote

Which bit don't you understand balski and which bit have I re-arranged.

The plane is stood on the runway/conveyor doing take off speed of 100mph, to hold it position in relation to its surroundings it has to apply thrust = to 100mph

 

[Balenza]

Dont think this ones 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 aircrafts 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?

[quote="balski" You have taken the OP's question and re-arranged it completely out of context.
Just reading through this jumble I have seen that Spacecat has given a good explanation .
Though being a physicist he ought to. icon_wink.gif

What are your credentials diyitall on the subject ? [/quote

Which bit don't you understand balski and which bit have I re-arranged.

The plane is stood on the runway/conveyor doing take off speed of 100mph, to hold it position in relation to its surroundings it has to apply thrust = to 100mph

Lets have you're credentials first then I might consider taking you seriously.
Does jobbing plumber sound about right ?.

Have you any experience in aviation at all ?.

 

[doitall]

If you mark a cross under the toy, when it gets to the checkout it will not have moved. even if you throw the box away, to get back to the end of the conveyor, it will need more speed than that of the conveyor belt

if the wheels were broken or had brakes and didnt turn then it wouldnt move off your cross, but it will have moved in space

The surface is moving, the plane is in the same spot all the time.

how can that be when a normal(not VTOL)aircraft needs airflow over its wings to take off and the plane in the video did indeed take off, if it hadnt moved from the spot as you say where did it get the lift from?

It's a toy and nothing is broken and no brakes, and no trust, yet it will reach the checkout without moving of the cross.

The plane in the video was not on a conveyor, it was supported by another force, e.g. the ground.

 

[tim west]

I think the first 8 words of Softus's OP should have given you an idea of what was to follow

 

[doitall]

Lets have you're credentials first then I might consider taking you seriously. icon_rolleyes.gif
Does jobbing plumber sound about right ?.

Have you any experience in aviation at all ?.

Would you like me to post my ppl

You could phone Bristol Airport and ask.

 

[Balenza]

Lets have you're credentials first then I might consider taking you seriously. icon_rolleyes.gif
Does jobbing plumber sound about right ?.

Have you any experience in aviation at all ?.

Would you like me to post my ppl

You could phone Bristol Airport and ask.

You can post whatever you like as long as its nothing to do with airplanes on conveyors as you ain't got a clue.

 

[tim west]

Would you like me to post my ppl

You could phone Bristol Airport and ask.

about the toy plane you fly down at tescos?

 

[doitall]

More of a clue than you that is quite obvious.

A plane needs a land speed to take off, 2400 rpm and 85 knots and I'm flying, assuming the elevator, ailerons, rudder are where they should be and you trim for the take off position.

However the conveyor is preventing forward movement so no air flow over the wings

 

[Balenza]

Diyitall wrote

and which bit have I re-arranged.

This...........

The problem we have is the runway is moving at takeoff speed say 100mph.

The Op stated

This conveyor belt has a control system that tracks the aircrafts wheels speed and tunes the speed of the conveyor belt to be exactly the same as the wheels, but in the opposite direction.

Where do you get the 100mph from ?. The control system is in place to match the conveyor speed with the wheel speed.

Do you know what a control system is ?

The pilot starts the engine, and has to do 100mph just to stop going backwards

No. The conveyor is at a standstill.
The control system will ensure that the conveyor only operates when the airplane begins to move forward.

Imagine a running machine and the person steps on. Nothing happens until the runner turns the speed control up and at the same he starts to move his legs.

Now strap a jet thrust engine to his back and watch him take off across the floor.
Might be a good idea to try this experiment on you. Can't speak for anyone else but I would be cracking up watching you being propelled of the end of the machine. lol

 

[tim west]

Seems they give out these pilots licences to just about anyone these days

 

[heatingman]

is there any luggage on this conveyor belt, if so its mine

 

[doitall]

Would you like me to post my ppl

You could phone Bristol Airport and ask.

about the toy plane you fly down at tescos?

Your argument is getting very weak Tim, and the toy plane didn't fly it moved in space as you kindly put it.

 

[tim west]

Your argument is getting very weak Tim

Something to do with the weak answers you've been giving perhaps?

 

[doitall]

while the conveyor belt moves in the opposite direction. This conveyor belt has a control system that tracks the aircrafts wheels speed and tunes the speed of the conveyor belt to be exactly the same as the wheels, but in the opposite direction.

So the plane is running on the spot.

Unless the wheels go faster than the belt they're stood on there can be no forward movement.

and your jet pack theory is sound except the legs would not be in contact with the belt