conveyor belt and plane answered at last ??

[crank39]

In theory it should hover so long as the wind stays constant, but then again its nots hovering as it has air flow of the wings so far as they're concerned they are moving forward

 

[doitall]

Aircraft with landing gear down, stationary on a conveyor, then a 300mph headwind hits it and the landing gear is retracted, what happens?


Ooooooooooooh!

The plane would probably turn upside down and blow away.

 

[joe-90]

It's got nothing to do with the wheels. If the wheels don't turn at double the speed - then you have no question. It's not viable. No point discussing it.

We know it's not viable but it's the rules laid down in the problem.

The plane can't take off, and it has every thing to do with the wheels, because they are what the plane is sat on and has to match the conveyor speed.

It doesn't matter what anything else is doing, if the wheels and belt match speeds the toy is stationary.

The question isn't a question if it isn't possible. You need to re-read the question.

 

[doitall]

The question is can the plane take off given certain conditions.

The answer is No.

And it doesn't matter how big the engine is.

 

[joe-90]

A question that isn't viable isn't a question. It's just nonsense.

 

[doitall]

A question that isn't viable isn't a question. It's just nonsense.

Of course it's nonsense, pleased you have seen the light at last.

Either the question is flawed or it's a trick question to get poster wound up, but either way the plane ain't going no-where.

 

[joe-90]

You simply don't understand the question.

 

[crank39]

Joe, the plane needs forward motion to take off, if the ground below it is constantly being dragged from under it then its physically impossible to move forward if the 2 speeds are matched simple as, no ifs or buts, the only way for the plane to move forward would be to throttle up and increase its thrust without the ground/conveyor speeding up

 

[joe-90]

You need to read newtons third law.

 

[securespark]

It's got nothing to do with the wheels. If the wheels don't turn at double the speed - then you have no question. It's not viable. No point discussing it.

Yet discussing it you are.

 

[Trazor]

It doesn't matter what anything else is doing.

What matters is that the engines of a jet aircraft are producing 120,000lb of thrust. Newtons third law of motion says that every action has an equal and opposite reaction.
You seem to think that virtually frictionless bearings in the planes wheels can negate this force.

if the wheels and belt match speeds the toy is stationary.

The only time the plane and the conveyor belt can be stationary is when the plane is not moving.

The only time when the conveyor can move is when the plane is MOVING FORWARD as the conveyor reacts to the wheel movement generated by the plane.

If the plane stops, the wheels stop moving, therefore the conveyor stops.

You cannot have the the conveyor moving at 100 mph whilst the plane is stationary, because it would be the conveyor producing the speed independently, not by reacting to the wheels.

 

[doitall]

You cannot have the the conveyor moving at 100 mph whilst the plane is stationary, because it would be the conveyor producing the speed independently, not by reacting to the wheels.

The conveyor is moving independently, exactly the same as the Tesco and treadmill belt.

In case you didn't know the conveyor is going in the opposite direction as the plane.

 

[Trazor]

The conveyor is moving independently.

Read the original question, it should react to the wheels not move independantly

In case you didn't know the conveyor is going in the opposite direction as the plane.

Thought that was a given, Are you on drugs........

 

[AronSearle]

Now lets say the magic tarmac is moving at 85knots, all things being equal I'm not going anywhere.

Why, what is providing traction/friction to stop the plane?

I don't think you understand what a wheel is, hint, there is a reason wheels have brakes fitted to them.....

It doesn't matter what anything else is doing.

What matters is that the engines of a jet aircraft are producing 120,000lb of thrust. Newtons third law of motion says that every action has an equal and opposite reaction.
You seem to think that virtually frictionless bearings in the planes wheels can negate this force.

 

[doitall]

Why, what is providing traction/friction to stop the plane?

I don't think you understand what a wheel is, hint, there is a reason wheels have brakes fitted to them.....


What matters is that the engines of a jet aircraft are producing 120,000lb of thrust. Newtons third law of motion says that every action has an equal and opposite reaction.
You seem to think that virtually frictionless bearings in the planes wheels can negate this force.

why do we need friction, the conveyor is moving at 100mph and you sit the plane on it with no engine it will travel at the same speed as the conveyor and the wheels wont be turning.

Now start the engine and you need a force/energy to stop the plane travelling along the belt, Grasshoppers 1st law. The wheels are now turning at the same speed as the conveyor.

For the plane to take off the wheels have to go faster than the belt, which they are not allowed to in the question.

You can fit 10 jumbo jet engines if you like and have 12,000000 lbs of trust if you like, the wheels cannot go faster than the belt without breaking the rules.