A plane on a conveyor belt

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idd, should be thought along the lines more of when you rip a table cloth from underneath your plates etc, providing theres minimal friction they are not hardly going to move, so if they had something pushing them the other way at the same time they will obviously go the other way, even with the table cloth being ripped under them. In real world this is obviously providing the forward force is greater than friction/coefficient etc.
 
[FnG]magnolia;11087958 said:
I can't wait until the same thread happens in 4 weeks time :)
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I can, I think I could quite happily go the rest of my life without hearing this question again. :)

I don't object to people not understanding the question or not knowing physics (I've never taken a physics class in my life so lots of it goes way over my head) but what I do find wearing is when it seems people don't even try to understand, especially after repeated explanations. I really don't care about knowledge or ability provided people actually try - whether that be at understanding, sports or whatever.
 
Agreed with the above. I didn't mind Helium not grasping the idea. But people keep coming in and stating that it can't, followed by several pages of repeated theory. And then someone else (jas) comes in and it repeats. It's like Groundhog Day. Read the thread, what do you think we've been talking about for 8 pages?
 
Everyone is mentioning the lack of airflow over the wings. Think of it like this. If you're running you'll feel air rushing past you. On a conveyor belt, although you are stationary relative to some point on the ground, the fact you are running to stay in that same place rather than being whisked back by the belt means there will be airflow and therefore airflow of the wings if the plane was on the belt instead. Of course, on a treadmill at the gym, you don't feel the air rush past you as you're not running that fast.
 
Ken said:
Everyone is mentioning the lack of airflow over the wings. Think of it like this. If you're running you'll feel air rushing past you. On a conveyor belt, although you are stationary relative to some point on the ground, the fact you are running to stay in that same place rather than being whisked back by the belt means there will be airflow and therefore airflow of the wings if the plane was on the belt instead. Of course, on a treadmill at the gym, you don't feel the air rush past you as you're not running that fast.
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So if you run fast enough on a treadmill you'll create wind? :\
 
Ken said:
Everyone is mentioning the lack of airflow over the wings. Think of it like this. If you're running you'll feel air rushing past you. On a conveyor belt, although you are stationary relative to some point on the ground, the fact you are running to stay in that same place rather than being whisked back by the belt means there will be airflow and therefore airflow of the wings if the plane was on the belt instead. Of course, on a treadmill at the gym, you don't feel the air rush past you as you're not running that fast.
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The plane isn't stationary though, your thinking as if the plane is a car and wind is rushing over the roof, this is wrong.
 
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Ken said:
Everyone is mentioning the lack of airflow over the wings. Think of it like this. If you're running you'll feel air rushing past you. On a conveyor belt, although you are stationary relative to some point on the ground, the fact you are running to stay in that same place rather than being whisked back by the belt means there will be airflow and therefore airflow of the wings if the plane was on the belt instead. Of course, on a treadmill at the gym, you don't feel the air rush past you as you're not running that fast.
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No that's definitely wrong.:)

Read the thread. The plane doesn't have to try and stay stationary. The air is stationary relative to the plane (assuming zero friction in the wheel axles). The thrust provided by the plane engines propels the whole plane forward regardless of the speed of the wheels, or the original airflow over the wings.

The forward motion of the plane relative to the ground cannot happen without motion relative to the air, and vice versa.
 
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MookJong said:
The plane isn't stationary though, you thinking as if the plane is a car and wind is rushing over the roof, thsi is wrong.
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The plane is stationary relative to the ground as the conveyor belt matches the plane's speed. The plane is however overcoming gravity and drag when it does take off.
 
Ken said:
The plane is stationary relative to the ground as the conveyor belt matches the plane's speed. The plane is however overcoming gravity and drag when it does take off.
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No, the plane moves forwards through the air as the wheels connecting it to the conveyor belt spin freely. It's this movement through the air that produces lift.
 
Zefan said:
No, the plane moves forwards through the air as the wheels connecting it to the conveyor belt spin freely. It's this movement through the air that produces lift.
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How can there be any forward movement if the belt matches the plane's speed. It takes off because there is airflow. This airflow is due to the fact the engines are producing thrust and keeping the plane from moving backwards along the belt. Because it's moving, although not relative to the ground, there is airflow and therefore vertical component to wings i.e lift.
 
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