Going to settle the plane on a treadmill once and for all.

[ballz2wallz]

You have to address it from the reality of the situation:

If what you're saying is true (and ideally, it would be), then the same would apply if the jets weren't on. If the treadmill was still going the same speed and the jets weren't on, the plane, in your scenario, wouldn't move; only the wheels would move under the plane. But that just isn't the case. If they plane's jets were not on, the plane would follow the treadmill back. Therefore, you have to account for the fact that the jets are fighting a negative force against the treadmill.

[7960]

Originally Posted by Ardentfrost

But since the motile function is exerted from the jets, not the wheels, wouldn't that just mean the wheels would be moving twice as fast as the plane is moving forward?

That's why with absolutely zero friction the plane would take off exactly like any other plane. It would look, sound, and feel like any other takeoff. With no friction a plane would take off on a treadmill just like any other plane, same takeoff speed and everything.

This whole time I've been saying friction adds a twist. The plane will still take off but adding in friction will change the takeoff a bit.

[ballz2wallz]

Originally Posted by 7960

This whole time I've been saying friction adds a twist. The plane will still take off but adding in friction will change the takeoff a bit.

I agree.

[7960]

Originally Posted by ballz2wallz

You have to address it from the reality of the situation:

If what you're saying is true (and ideally, it would be), then the same would apply if the jets weren't on. If the treadmill was still going the same speed and the jets weren't on, the plane, in your scenario, wouldn't move; only the wheels would move under the plane. But that just isn't the case. If they plane's jets were not on, the plane would follow the treadmill back. Therefore, you have to account for the fact that the jets are fighting a negative force against the treadmill.

All the jets would have to do is overcome the initial coefficient of friction, which would be minimal. Like I just said above it would take some amount of time to overcome that, but the engines of *any* plane can do that.

All this talk about jets sometimes gets people thinking this only works because "jet engines are strong." That's not the case. Any plane with the power to take off should be able to overcome the friction. Put an old bi-plane on a treadmill and start it going backwards at 100mph (far faster than take-off speed for a bi-plane) and when you turn the engine on it will overcome the previous backward momentum and friction and eventually take off. It will take a bit longer because it has to overcome backward motion, but it will take off.

[Ardentfrost]

Yes, the friction on the wheels (bearings and created by the ground) would reduce the amount of thrust going to forward mobility, however, b2w's claim that if the plane is started off moving backwards then the thrust must overcome that backward momentum doesn't make sense. As I pointed out in my long post on the previous page, the thrust has little to do with the plane moving backwards. Almost immediately the plane would be moving forward (relative to an onlooker) and the wheels would be spinning the speed of forward mobility plus the speed of the treadmill (that is in rotational speed at the circumference). The only twist the friction would add is a reduction in the amount of thrust available to get the plane moving. This could cause the need for a longer take off (to reach the desired speed for lift), but given that plane wheels should be pretty efficient, it shouldn't be too much.

And 7960, the bi-plane doesn't have to overcome it's backward motion, it has to overcome the friction the wheels will generate when going 100mph before moving forward. That should happen pretty fast (I'm not saying instantly, but very quick, like before the propellers are even going top speed for take off). If you were relative to the actual plane (like, the pilot of whatever) then you would feel like you were going 100mph backwards, then very quickly slowed and started going in the opposite direction.

And, of course, if the system were frictionless (but still moving backwards) the change in direction would be immediate.

[7960]

Originally Posted by Ardentfrost

Yes, the friction on the wheels (bearings and created by the ground) would reduce the amount of thrust going to forward mobility, however, b2w's claim that if the plane is started off moving backwards then the thrust must overcome that backward momentum doesn't make sense. As I pointed out in my long post on the previous page, the thrust has little to do with the plane moving backwards. Almost immediately the plane would be moving forward (relative to an onlooker) and the wheels would be spinning the speed of forward mobility plus the speed of the treadmill (that is in rotational speed at the circumference).

I believe we said that (I know I did).

And 7960, the bi-plane doesn't have to overcome it's backward motion,

I was saying if the treadmill started up and got the plane moving backwards and *THEN* the propeller started after the plane was moving backwards.

it has to overcome the friction the wheels will generate when going 100mph before moving forward. That should happen pretty fast (I'm not saying instantly, but very quick, like before the propellers are even going top speed for take off). If you were relative to the actual plane (like, the pilot of whatever) then you would feel like you were going 100mph backwards, then very quickly slowed and started going in the opposite direction.

Again, isn't that what I said?

[Ardentfrost]

What about if there were motherfucking snakes on the motherfucking plane?

That just throws all previous ideas out the window!

[7960]

snakes on a plane?!?!

how about fucking SCORPIONS on a plane?!?!?


Scorpion stings man on a plane

[Emfuser]

Originally Posted by Dumpy Dooby

Oh, and yes the plane takes off.

On a side note: I actually used to enjoy going into forums and starting these threads, and then trolling the people that knew what they were talking about. I would make up all sorts of funny shit like "the tires would get really hot and become sticky, causing the plane to stick to the ground and not take off." It was so funny. I won't do that here, though.



It's difficult to explain to people that just don't "get it." But yes, the plane takes off because the wheels freespin. They are only there to keep the plane from hurting its belly. Imagine one of those planes that can take off from the water. Stick some ice on the bottom of those little skis and stick it on a treadmill. Will the treadmill stop it? Probably not. What about the current when the plane is in the water? Does that prevent it from taking off? Not really.

The treadmill would have an impact, but not much because it's pushing/pulling (depending if it's a plane or a jet) against the wind, rather than using the wheels to make it go forward. Take all of the wheels off of a car, and try to go somewhere, will it move? No. Take the wheels off of a plane, and try to go somewhere, will it move? Yes.

It absolutely astounds me just how many people don't understand this.

[AVengeance]

Originally Posted by Emfuser

It absolutely astounds me just how many people don't understand this.

The biggest reason is that people create their own assumptions and images in their minds. When you say "plane on a treadmill tries to take off" they immediately think- okay, the plane is going to be thrusting, the treadmill is going backwards, and the plane is just sitting still- of course it can't take off, because it would have to levitate straight up! My wife even said this (and she's college educated) before I finally explained that her mind had made some assumptions based on the question, and that's why she was answering it incorrectly. When someone asks "will the plane take off" many people ASSUME the question is "will the plane take off without moving forward" because of what they have observed with people running on a treadmill.

It's amazing how our own factual observations can skew the way we think about a question and determine its answer. This is actually useful in debate, I think, to point out to someone how easily they'll assume incorrect things, even though the assumptions are based on fact.

[ballz2wallz]

It's anti-intuitive. You really have to break it down. I'm somewhat educated, and even I needed to be convinced.

[7960]

Originally Posted by AVengeance

The biggest reason is that people create their own assumptions and images in their minds.

Yep.

I used to ask an extra credit question on a logic test (when I taught) and you'd be surprised how many kids didn't understand logic but got it right and how many got 100% on the test but had no fucking clue what the (right) answer was to the question.

the question:

It's 3:22 and a boat with a porthole is sitting at a dock. The porthole is 3' 4" above the water line and the tide is coming in. If the tide rises at a rate of 5" every 25 minutes, how long will it be until the water reaches the porthole?

I was constantly amazed at how many "dumb" kids laughed when they read it and how many "smart" kids spent 15 minutes figuring out "the answer."

[ballz2wallz]

Originally Posted by 7960

Yep.

I used to ask an extra credit question on a logic test (when I taught) and you'd be surprised how many kids didn't understand logic but got it right and how many got 100% on the test but had no fucking clue what the (right) answer was to the question.

the question:

It's 3:22 and a boat with a porthole is sitting at a dock. The porthole is 3' 4" above the water line and the tide is coming in. If the tide rises at a rate of 5" every 25 minutes, how long will it be until the water reaches the porthole?

I was constantly amazed at how many "dumb" kids laughed when they read it and how many "smart" kids spent 15 minutes figuring out "the answer."

I used to ask a similar extra credit question:

Why don't polar bears eat penguins?

Mind you, I was teaching organic chemistry, and I always asked this when talking about polarity.

[7960]

Originally Posted by ballz2wallz

I used to ask a similar extra credit question:

Why don't polar bears eat penguins?

Mind you, I was teaching organic chemistry, and I always asked this when talking about polarity.

I had parents call and bitch that their kid "deserved the extra credit for figuring it out."

It was eveyrthing I could do not to laugh.

[Ardentfrost]

I had a quiz one time that had a lot of questions for the time given, but the directions were this:

1. Read over the entire quiz before starting.
2. Finish within 15 minutes.

The last question on the quiz (which was like 2 pages front and back) said "Do not answer any questions, just write your name on the front page and turn in the quiz when time is up"

That wasn't logic based, it was following directions, but I thought it was funny. So many kids got pissed about that one.

[DosEquis]

Originally Posted by Ardentfrost

I had a quiz one time that had a lot of questions for the time given, but the directions were this:

1. Read over the entire quiz before starting.
2. Finish within 15 minutes.

The last question on the quiz (which was like 2 pages front and back) said "Do not answer any questions, just write your name on the front page and turn in the quiz when time is up"

That wasn't logic based, it was following directions, but I thought it was funny. So many kids got pissed about that one.

I have had that one before. Half the class is sitting there going while the others are stressing to get it done in 15 minutes.

[Dumpy Dooby]

Originally Posted by ballz2wallz

I used to ask a similar extra credit question:

Why don't polar bears eat penguins?

Mind you, I was teaching organic chemistry, and I always asked this when talking about polarity.

That reminds me of one that I use.

Why didn't George Washington sign the Declaration of Independence?

The question is leading one to believe that George Washington made an active decision to not sign the Declaration, which wasn't the case at all. He was just busy fighting some redcoats.

I used that one when we did that gay thing where high school kids get sent to the elementary schools to tutor them and be a good influence or whatever.

[Donkey®]

I am really hoping more of you draw pictures so I can laugh.

[Dumpy Dooby]

Like I mentioned earlier, I used to love to troll these threads. Here are some of my posts...

• Perhaps unbeknownst to yuo, as the wheels start spin faster, they would heat up and make them stickyer. They would then grab the treadmill, and with increased friction, the plane would take off. The forces at play here would rise to such extrimes, that it would pull the treadmill up from the ground and take off with the treadmill dangling from the sticky wheels.
  
• well ya, but what about the sticky tires? They would surely make the plane take off.
  
• well the sticky wheels would stick it to the treadmill, of course it could never take off.
  
• hypocritical questions can't be tested. this being one of those, it can't be tested, being one of those. Those being a hypothetical question, and the hypothetical question being the one regarding planes and treadmill.
  
• the spinning wheels would blow the wind upwards under the wings, and cause massive lift. It would not never take off.
  
• Building a treadmill that size is like trying to exceed the speed of sound. They are both impossible.
  
• The wheels would create enough lift. Because they get sticky. duh!
  
• The thrust alone would lift the plane. Plus we've already established that the sticky tires would create substantial lift on their own Because the stickier the tires get, the lighter the plane gets. Because the air in the tires turns to helium.
  
• Well it IS traveling forward, relative to the treadmill. With enough forward motion, wind is unnecessary.

I didn't post the quotes from the people to whom I was responding because it's kind of irrelevant. It was so hilarious messing with everyone though. People were taking me seriously even though I was contradicting myself left and right and making no sense.