NO...Jet engines creates thrust, which moves the plane forward because the thrust pushes the plane. The wheels are the *****es, they just roll along and in this case isolate the plane from any drag or affect from the ground being manipulated below it. I'm right, guaranteed.....
The reason the toy car goes forward in your experiment is because the car is pushed at a speed faster than the treadmill is going not because the force is "external". If you push the toy car with less force, then it would be taken off the back of the treadmill rather than getting pushed off the front of the treadmill. This is because real treadmills are set for a certain speed and don't match the wheels of a toy car exactly, while this exact rotational match is assumed by the problem. I guess we can get to 8 pages after all...
DING DING F-IN DING!!!!!!!!!!!!!!!! Dude Payne, this is your cup of coffee......take a long & deep smell
Dude, it's really simple. I would agree with you if it said that conveyor speed equals plane speed. The plane takes off easily. However, that isn't the case when wheel speed equals conveyor speed. Get it? Wheel speed & Plane speed are two completely different things. When a wheel travels along something going the same speed in the opposite direction there is no movement. Basic stuff really. With no ground speed for the wheel, then the plane has no ground speed and therefore the plane doesn't get any airflow.
assume infinite wheel speed, this would lead to no friction. the closest we can come to that condition is a hovercraft. a curtain of air allows for little ground friction, the prop thrusts the craft forward with its prop. strap yourself to metal rails and sit on an ice'd pond, can't generate friction for movement, but you could move forward if you were in a plane taking off.
I dont get why this is is such a trick question... Does a plane fly in the air at 33,000ft even though the wheels are NOT in motion? The engines create thrust which propel the plane forward. PERIOD. The traction which pushes the plane forward is atmospheric gas, not the ground it sits on. The Jets push the plane forward. The proper question to ask would be, if there was a 250mph tail wind (747's takeoff at 250mph last i remember) would the plane still be able to take off if travelling at 250mph? Think about it...
People are getting hooked up on the fact that planes aren't wheel driven, they think they are smart and end up not looking at the most basic definitional problems. Wheel Speed - Conveyor Speed = Plane Ground Speed. Wheel Speed = Conveyor Speed by the problem statement. Therefore 0 = Plane Ground Speed. Now, if you want to argue that it is an impossible problem statement, go ahead.
in the case of the original question you are to assume that the wheels speed is matched no matter how fast it travels. that would create a lack of friction for forward movement.
Let me try to explain this with an alternate thought experiment... Take a toy wagon, put it on a real treadmill. Let the treadmill run but hold the wagon in place by putting your hand on the back of the wagon (assume the front wheels aren't swiveling so you don't have steering problems. Now whatever speed the treadmill runs, the wheels "freewheel" and the wagon stays fixed (because you are holding it). The force diagram of you holding the wagon in place is no different than if you provided thrust with an engine (forward force vector), but since the treadmill/wheel system is designed to keep the speeds matched, there is no forward motion in either case.
Engine directs thrust back....which makes the engine mounted to the wing push the wing forward and the whole plane moves foward. Uhhh.....PERIOD. How will the rotation of the wheels alter this? You take cream with that coffee?
yar i'm not seeing the train of thought on how people think the plane can move forward. i still agree with my first post, none of the banter since has changed that.
Just thought about this again, the conveyor belt could travelling at a 100000mph dyno. The plane would still take off because this aint no flintstones mothafcking aeroplane gus. It relies on Jet thrust and not grounded torque. So the issue here is how fast the air is moving, not how fast the "conveyor belt" is moving. Much in the same way a bald eagle can fly even if it isnt "running for it".
Dude, you have to adhere to the problem statement first. If you want to argue the validity of the problem statement, go ahead.
okay, it's 2am....I'm headed to bed, catch you when the sun comes up. Unless of course someone puts the earth on a giant treadmill and.... night boys!
no it only relies on thrust if it's a VTOL type aircraft, otherwise it depends on Bernouli's Principle, drag over the wing.
i think i've figured out how to explain it better. the treadmill would not have to increase it's speed past the wheel rotation of a normal non moving runway. here is why. in any rotational object travling against a surface the surface speed is match excactly to it. car on road or car on dyno. the reason a car on the dyno does not travel forward is becouse the dyno rollers are in a fixed position relitive to the car. the rollers and wheels travel past each other at the same speed. if one or the other were to a different speed then you would get scrubbing. i.e. burnouts and skidding at a stop. the movement of the treadmill past the wheels is a non issue for the plane since it generates forward movement from the engines and not the wheels. when you drive down the street, your forward movement causes the road to match your speed.
