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Farrok posted:As I pilot myself, I am completely shocked that the dude they hired to fly that ultralight actually thought this ridiculous myth was plausible...seriously, I don't understand the vehemence about this myth, its so loving stupid. A commercial (and former military)pilot that I know was insistent that the plane couldn't take off, going so far as to say we all didn't understand high school physics if we thought it would.  As for the question itself, it is worded brilliantly and I do not think that the original author (whoever it was) made a mistake. It actually reads like an exam question since it is very specific about how the situation is setup. I find the debate around it really interesting because it shows just how much of our own pre-conceived notions we bring into any situation. Despite the question being worded very specifically most people read it incorrectly at first because it is outside what we would usually experience.
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Feb 1, 2008 03:49
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Senor Tron posted:I find the debate around it really interesting because it shows just how much of our own pre-conceived notions we bring into any situation. Despite the question being worded very specifically most people read it incorrectly at first because it is outside what we would usually experience. Exam questions try to be as sneaky as possible. Those specifics just cloud the situation. 
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Feb 1, 2008 04:11
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I just watched the M5 Industries tour on discovery.com, and honestly, the "pencil" thing wasn't that bad. I thought he was going to bust into a grin when he started in on the cameraman, like "hey, gotcha now, you can't say anything because you're filming!". Jamie's a little OCD - and it *is* his shop, M5 Industries, whether MythBusters films there or not. Did you see the "CLEAN UP OR DIE" sign? I've read numerous times in interviews that he *hates* when people use the shop and then don't clean up the mess they made. I also read where he stated that he and Adam don't really have a lot in common. They work together (and he's the person who recommend Adam to the producer for the "other host" role), but they don't "hang out" together. There's nothing wrong with his neat-freak-ness; it's his business that he built from the ground up, and he has the right to be a little picky about having the proper supplies in the proper places.
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Feb 1, 2008 04:40
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What is the exact question? I don't think I've seen anything other than "Plane on a treadmill."
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Feb 1, 2008 04:40
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Cojawfee posted:What is the exact question? I don't think I've seen anything other than "Plane on a treadmill." "A plane is standing on a runway that can move (some sort of band conveyor). The plane moves in one direction, while the conveyor moves in the opposite direction. This conveyor has a control system that tracks the plane speed and tunes the speed of the conveyor to be exactly the same (but in the opposite direction). Can the plane take off?" edit: now that i re read the original problem it is kinda obvious the author knew perfectly well what he was asking. He specifically states the ENTIRE runway can move, not just a small treadmill sized one. bag of a bee fucked around with this message at 08:54 on Feb 1, 2008 |
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Feb 1, 2008 08:49
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It doesn't say anything about keeping the plane stationary, just that the conveyor belt moves at the exact opposite speed. No matter how fast the belt moves, it can't move the plane unless the wheels are locked. Sure there is some force that gets transferred to the plane via the wheels, but the propellor or jet is going to outweigh that force.
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Feb 1, 2008 09:31
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James IV posted:edit: now that i re read the original problem it is kinda obvious the author knew perfectly well what he was asking. He specifically states the ENTIRE runway can move, not just a small treadmill sized one. 
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Feb 1, 2008 16:14
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Dr. Memory posted:What difference would that make? I think the difference is that it's a hypothetical situation that was never meant to be tested in reality.
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Feb 1, 2008 18:21
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Dr. Memory posted:What difference would that make?
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Feb 1, 2008 19:37
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I would suggest using matchbox cars to simplify this enough for anyone to understand. As Adam so plainly showed with the RC car, when in neutral the car rolls easily along the runway and any force which is applied independent of the wheels can move it forward. So, I would strap a bottle rocket to a matchbox car on a superfast treadmill to see if it makes the car go forward. It's exactly the same principle being tested as with an aeroplane, but done in such a way that even the dimmest person would have to see what it going on. After all, if it can move, then it can take off.
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Feb 2, 2008 16:12
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The plane is supposed to be stationary relative to a person standing still on the ground, off of the treadmill. If a treadmill is moving backwards at one hundred miles per hour with (for simplicity's sake) a car on top of it moving forward at one hundred miles per hour, the car would appear to be stationary. Now put wings on the car. Do the wings generate lift? No, they don't. Why not? Because there is NO AIR PASSING OVER OR UNDER THE WING. The Mythbusters didn't even understand the question. I hate this episode so much.
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Feb 2, 2008 21:06
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n0n0 posted:The plane is supposed to be stationary relative to a person standing still on the ground, off of the treadmill. If a treadmill is moving backwards at one hundred miles per hour with (for simplicity's sake) a car on top of it moving forward at one hundred miles per hour, the car would appear to be stationary. I wish I lived in your world where I could strap wings onto my car and fly it to Europe for the weekend. Alas, Ron Weasley doesn't return my calls.
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Feb 2, 2008 21:36
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n0n0 posted:The plane is supposed to be stationary relative to a person standing still on the ground, off of the treadmill. If a treadmill is moving backwards at one hundred miles per hour with (for simplicity's sake) a car on top of it moving forward at one hundred miles per hour, the car would appear to be stationary. With a plane, the wheels are basically roller skate wheels. The plane engine is using the air, not the ground, to generate forward velocity and moving the plane forward at 100 MPH independent of the wheels. If the treadmill is going the other direction at 100 MPH, the wheels just free-spin extra fast and the plane continues to move forward at the exact same 100 MPH, reaches takeoff velocity and launches, regardless of the counter velocity applied by the treadmill.
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Feb 2, 2008 22:25
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n0n0 posted:The plane is supposed to be stationary relative to a person standing still on the ground, off of the treadmill. If a treadmill is moving backwards at one hundred miles per hour with (for simplicity's sake) a car on top of it moving forward at one hundred miles per hour, the car would appear to be stationary. I really don't understand the point of this line of argument. You want the mythbusters to test whether a plane will take off if there's no air moving under the wing? Of course it won't. If they could somehow get a conveyer belt to move SO FAST that the friction on the wheels alone will counter any forward movement by the plane - which is nigh-impossible - and the plane stood still - it wouldn't take off. Happy? There's your answer.
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Feb 2, 2008 22:55
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n0n0 posted:The plane is supposed to be stationary relative to a person standing still on the ground, off of the treadmill. Show me where in the question it says the plane is stationary. Hint: You can't, because it's not there. In fact, the question states that the plane moves. What you think the plane is "supposed" to do is irrelevant, what the question actually says is all that matters. quote:If a treadmill is moving backwards at one hundred miles per hour with (for simplicity's sake) a car on top of it moving forward at one hundred miles per hour, the car would appear to be stationary. Within this single sentence you have switched reference frames from the earth to the belt. You say that the treadmill is moving backwards. You of course mean relative to an observer on the earth. You then go on to say that the car is moving forward. Relative to the observer on the earth, who you JUST USED to define the belt's movement, the car is NOT moving forward. This is because you have switched your reference frame in mid stream for the sole purpose of erroneously defining the car as "moving." There are a number of reasons why this is dumb. quote:I really don't understand the point of this line of argument. You want the mythbusters to test whether a plane will take off if there's no air moving under the wing? Of course it won't. Exactly. We don't need to test that a plane can't take off with no airspeed, it's a basic fact, a given. Planes need airspeed to fly. That's how they work. It would be like asking if a car can drive when it's on it's roof because you are pushing the gas pedal. The car's wheels spinning obviously don't do anything if they aren't touching the ground, it's not a question that needs to be asked. Elysium fucked around with this message at 00:23 on Feb 3, 2008 |
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Feb 3, 2008 00:09
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Elysium posted:Within this single sentence you have switched reference frames from the earth to the belt. You say that the treadmill is moving backwards. You of course mean relative to an observer on the earth. You then go on to say that the car is moving forward. Relative to the observer on the earth, who you JUST USED to define the belt's movement, the car is NOT moving forward. This is because you have switched your reference frame in mid stream for the sole purpose of erroneously defining the car as "moving." There are a number of reasons why this is dumb. If a planes wheels are good enough, if the bearings (or whatever) are all super slick and bitchin, and the runway "treadmill" were in perfect sync with the plane's engines, there would be no lift because the plane would still be stationary, moving forward at the same rate as the 'treadmill' moving backwards. Thinking more about it, it turns out that I may be completely wrong. But you are still some kind of an rear end in a top hat.
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Feb 3, 2008 01:23
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n0n0 posted:I should have said that the wheels were moving rather than the car. I mean, nothing is really MOVING. Only the wheels are turning. And the axles. And so on. What are you, some kind of an rear end in a top hat? To a more accurate adjustment to your analogy, instead of strapping wings to the car tie a rope (representing the propellers providing a plane thrust), when the rope is pulled the car will go forward, putting the car in neutral will still have it travel at same speed (with more resistance on the rope, this is what Adam showed with the toy car on the treadmill). Strap wings to the car and pull the rope fast enough giving it enough airspeed it will fly, you don't see wheels on a kite. For those to believe the plane can't fly they have to deny the existence platoon planes, water provides much more resistance then wheels ever will. keeper fucked around with this message at 01:57 on Feb 3, 2008 |
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Feb 3, 2008 01:54
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n0n0 posted:If a planes wheels are good enough, if the bearings (or whatever) are all super slick and bitchin, and the runway "treadmill" were in perfect sync with the plane's engines, there would be no lift because the plane would still be stationary, moving forward at the same rate as the 'treadmill' moving backwards. You're wrong but I won't comment about Elysium's assholeness.  I'll give you two ways to understand why you're wrong. Imagine you're looking at a car on a treadmill. The guy in control of the treadmill isn't that hot so he takes a half second to adjust to the car's position. So the guy in the car guns his engine and moves a ways on the treadmill before the guy can catch up. But he does and by adjusting the speed of the treadmill he can move the car backwards, forwards, or stationary on a painted line as long as the car engine is providing rotation to its wheels. With a plane and the same low reaction time operator, he can never keep it under control. The airplane starts to get some thrust and moves on the treadmill. The operator then starts gunning the treadmill but it seems to have no appreciable effect on the forward motion of the plane. No matter how fast he goes, 1000mph or otherwise, the plane keeps on moving forward. The operator can never make the plane move backwards, forwards, or keep it stationary as long as the propellers are providing thrust. As a second reason to understand why this doesn't work, imagine a car jumps off a small ramp at 25 mph. Imagine a plane flies in with enough thrust to go at 25 mph. Beneath both is a long treadmill running the opposite direction at 50 mph. When you drop either vehicle on the long treadmill, the results are wildly different. The car is going to lose all kinds of traction on impact and then go flying backwards at 25 mph even while the engine continues providing gas. The plane will get a little tire screeching and then will continue to move forward at 25 mph while its little wheels spin like 75 mph madmen. And it'll keep on going forward. The treadmill can't be "in sync" with the plane's motion because you can't exert direct control over a plane in motion by adjusting the ground (removing rolling friction from the question). You can with a car but you can't with a plane. In practical application, the only way to keep a plane stationary while it has thrust is if the thrust is so small that it matches rolling friction. So, if a plane is stationary at 1% thrust on a rolling treadmill, will it take off? No. Will a plane on regular tarmac at 1% thrust take off? No. At the levels of thrust that a "stationary on a treadmill" plane would be at, flight isn't even a possibility.
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Feb 3, 2008 03:45
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Clearly, a better way to test this is to use a model airplane and a small treadmill. Further, if the airplane has three (or more) wheels, and if the airplane is parallel to the ground when at rest, and if the wheels, axles, bearings, and -whatever- are all perfect, and if there is no risk of the wheels (for instance) exploding... and further, if the treadmill is in perfect sync with the airplane's mode of thrust, then there would be no movement. It is no different than a car. If a car were propelled by a rocket engine instead of four wheels, the same idea would apply. This only works with an 'active' treadmill, ie, a treadmill that has a motor in it. This is true of both the car and the airplane, UNLESS we could temporarily and selectively remove friction from the universe, in which case a passive (motorless) treadmill would suffice. ps, Ape Agitator, you are not very agitating at all. Sneeze Party fucked around with this message at 06:18 on Feb 3, 2008 |
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Feb 3, 2008 06:13
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Dude you are just rambling now. "if the treadmill is in perfect sync with the airplane's mode of thrust" what the gently caress does that even mean. Read the question, the airplane goes speed x, the treadmill is set to speed x in the other direction. If the airplane is not moving, the treadmill is not moving. The only question is what you consider speed to be relative to, because it's technically not specified, and for several reasons you should use a single fixed frame of reference outside the two objects to measure speed from, such as pointing a radar gun at them from the position of an observer.
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Feb 3, 2008 06:21
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n0n0 posted:Clearly, a better way to test this is to use a model airplane and a small treadmill. The better the bearings, the less likely this would be, not more. You would want bad bearings for this to even work at all, to provide friction so the motion of the wheels would actually influence the plane. If the bearings were perfect, it would be literally impossible for this situation to occur because the wheels are not attached to the axle in a plane, and so there would be no friction between the wheel and the axle to affect the plane's motion at all. For this to work even with a normal plane, you would have to be driving the treadmill at much faster than the plane to get it to stop. Driving it at the same speed as the plane would not work, because the wheels are essentially frictionless if well kept, and are barely having any effect on the plane at all. You could attach a motor to the wheels directly (as long as it wasn't done by attaching the wheels to the axle) and drive them backwards at the same speed as the plane, and it wouldn't have any effect; they would just be drug along the ground by the thrust of the engines while uselessly spinning against the plane's forward motion. You could bolt the wheels to the axle and keep them from spinning at all, and a plane could probably still take off, even if it had to rip up the tires to do so. Idran fucked around with this message at 06:23 on Feb 3, 2008 |
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Feb 3, 2008 06:21
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Idran posted:so the motion of the wheels would actually influence the plane. quote:If the bearings were perfect, it would be literally impossible for this situation to occur because the wheels are not attached to the axle in a plane, and so there would be no friction between the wheel and the axle to affect the plane's motion at all. quote:You could bolt the wheels to the axle and keep them from spinning at all, and a plane could probably still take off, even if it had to rip up the tires to do so. 1) The treadmill was stationary and locked. In this case, the airplane's thrust would propel it forward after the wheels had broken off of the fuselage. 2) The treadmill is moving. The airplane moves backwards until it falls off of the treadmill. Hilarity soon follows. I still maintain that I am correct. That with perfect synchronicity between the airplane's motor and the treadmill's motor, the airplane would neither move forward nor backward. It would also never fly. edit: this is stupid and I am done making GBS threads up the thread. How bout that Dirty Jobs show? Sure hope they don't run out of ideas!
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Feb 3, 2008 06:28
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n0n0 posted:It is no different than a car. If a car were propelled by a rocket engine instead of four wheels, the same idea would apply. Man, you just don't see the distinction at all. I can't believe you think a rocket propelled car can be kept from motion by a treadmill. Do you think that rockets and airplanes have a different method of propulsion when they leave the ground? Do you think that when planes land that they are instantly stopped by the equivalent of a relative treadmill running opposite their flying speed? Okay, take airplane out of it entirely. You've got a jeep. Drive the jeep regularly. How fast does the treadmill have to go to counteract movement? Okay, now put the jeep in neutral and tie the winch on the bumper to a tree. How fast does the treadmill have to go to counteract the movement the winch would cause? Turn the winch on. How fast does the treadmill have to go to counteract this new forward movement? Edit: This is better, from the producer of the show. Dan Tapster posted:Dear all, Edit: n0n0 posted:I still maintain that I am correct. That with perfect synchronicity between the airplane's motor and the treadmill's motor, the airplane would neither move forward nor backward. It would also never fly. How fast does a treadmill have to go to counteract the speed of a guy riding a skateboard on it? Does it matter if it is going 1, 5, or 10 mph? Does it matter if it's going backwards? Think about that question and you should understand why it's different. http://www.youtube.com/watch?v=XQTTI0dr5So Oh great, you're going to wallow in your ignorance as soon as anyone challenges you to back up your assertions. Wonderful. Ape Agitator fucked around with this message at 06:40 on Feb 3, 2008 |
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Feb 3, 2008 06:30
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Actually the producer's explanation is pretty dumb. He does a good job explaining how the belt has no effect on the plane, but he does a horrible job of defining speed. He jumps back and forth between the frame of reference of the earth/air and the belt for arbitrary reasons, and says ridiculous poo poo like "At take off speeds, the plane will ALWAYS move forward and will NEVER stay where it is." We know what he means, but that sentence is pretty loving dumb, if the plane is moving at takeoff speed (obviously he is using the airspeed frame of reference) why would it "stay where it is" also using an airspeed frame of reference? He just said it was moving at takeoff speed! The only reason people think it would stay still is because they are using a belt frame of reference. Then when he goes on to the running/skateboard analogy, he starts out from the belt frame of reference, and then immediately switches to the earth frame of reference, it's dumb and countermands the true argument that he should be making about figuring out the proper single frame of reference and using that to define all movement and speeds. Ape: This is a much better link for showing how the speed of the treadmill basically has no effect on the movement of the plane: http://www.youtube.com/watch?v=4owlyCOzDiE Elysium fucked around with this message at 06:48 on Feb 3, 2008 |
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Feb 3, 2008 06:44
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No, seriously, I just wanted to stop making GBS threads up the thread. I stand corrected. I was thinking of it wrong.
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Feb 3, 2008 06:47
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And this ladies and gentlemen is why this topic is banned in GBS.
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Feb 3, 2008 06:58
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Darth Freddy posted:And this ladies and gentlemen is why this topic is banned in GBS. Rather than ban the topic, we should be banning the people stupid enough to think the plane doesn't take off.
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Feb 3, 2008 18:22
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IRQ posted:Rather than ban the topic, we should be banning the people stupid enough to think the plane doesn't take off. Only after it's been explained to them and they still relent. Sadly, most people don't remember what they learned in high school physics six months after they had it.
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Feb 3, 2008 23:40
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IRQ posted:Rather than ban the topic, we should be banning the people stupid enough to think the plane doesn't take off. To be fair at first I was one of those people who thought it would stand still. It took me a bit to figure out it was all about the propulsion from the props. Though I do agree a lot of bans were handed out the last time the topic got started
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Feb 3, 2008 23:44
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Is anyone else watching the Puppy Bowl on Animal Planet? http://animal.discovery.com/tv/puppy-bowl/puppy-bowl.html I didn't know this existed until about five minutes ago, and now it's the only thing I ever want to see on Animal Planet. How is this not the only thing on Animal Planet? Here's a clip from last year's event: http://www.youtube.com/watch?v=zXT-sJcJka4 Ironically, I usually hate it when an educational channel dumbs down its programming. But it's nice to see a puppy on Animal Planet who's not emaciated and homeless or seriously injured.
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Feb 4, 2008 00:02
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Jack Gladney posted:Is anyone else watching the Puppy Bowl on Animal Planet? I just turned into it and it has to be the stupidest thing I have seen all week. I am also smiling and laughing harder then I have all week so it is great. As for the poor dogs that don’t get to look like that I do recommend donating to the SPCA, I try to as often as I can, every little bit helps.
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Feb 4, 2008 01:03
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Darth Freddy posted:To be fair at first I was one of those people who thought it would stand still. It took me a bit to figure out it was all about the propulsion from the props. Though I do agree a lot of bans were handed out the last time the topic got started I think at first blush it catches a lot of people, including me. That's presumably why the question was created in the first place, as some have suggested it's a trick question intended for teaching. The car scenario is a relationship between two things: the car and the treadmill. The grounded plane scenario is a relationship between three things: the plane, the treadmill, and the standing air. The treadmill cannot affect the interaction between the plane and the standing air which is precisely where the trick of the question comes in. It's why a car without wheels can't do anything but a plane without wheels can. It presupposes an impossible situation that only attentive students will catch. Most will accept the premise unquestioningly and dive into the meat of "will it fly" without figuring out that the entire premise is broken. I know I had to go so far as to think about how you'd practically setup an experiment before my lightbulb went on.
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Feb 4, 2008 02:38
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McSpanky posted:Only after it's been explained to them and they still relent. Sadly, most people don't remember what they learned in high school physics six months after they had it. Fair enough, I'm just tired of the dumb debate. At least "nOnO" did kind of relent after it being explained 20 times.
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Feb 4, 2008 04:57
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Jack Gladney posted:Is anyone else watching the Puppy Bowl on Animal Planet? The Puppy Bowl has been my Super Bowl halftime entertainment for the last several years now. It beats the official halftime shows.
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Feb 4, 2008 05:28
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I've not seen this Pirate episode, so I have to ask... Does anyone know why Adam apparently thinks pirates talk like Warhammer Orks?
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Feb 4, 2008 09:03
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Filthy Assistant posted:I've not seen this Pirate episode, so I have to ask... Does anyone know why Adam apparently thinks pirates talk like Warhammer Orks? Because he liked pirates and wanted to have fun.
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Feb 4, 2008 13:52
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Filthy Assistant posted:I've not seen this Pirate episode, so I have to ask... Does anyone know why Adam apparently thinks pirates talk like Warhammer Orks? That's Adam's voice for pretty much everything not Adam.
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Feb 4, 2008 14:41
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IRQ posted:That's Adam's voice for pretty much everything not Adam. I actually don't think I've ever seen him do a voice besides himself before. I did like how Jamie was visibly annoyed by it.
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Feb 4, 2008 22:24
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Filthy Assistant posted:I actually don't think I've ever seen him do a voice besides himself before. If you're watching tonight's Bond myths episode, he trots out his all purpose Not-Adam voice again.
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Feb 7, 2008 03:05
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Maybe I missed something, but in the Pen Grenade, did they use a styrofoam/foam dummy? Doesn't that defeat the entire purpose of doing that test since any kind of explosive will probably destroy something made of styrofoam in close proximity?
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Feb 7, 2008 03:08
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