Will it take off?

[Champagne taste beer budget]

Oh My Goodness... []

And that's all I have to say on this matter.

[Jeff Matthews]

Sput, you're it. The Cecil guy got me thinking with the A=A+5 argument. I think that could be my flaw, but am not totally sure.

Here's what I want to know. The plane's wheels are on the treadmill. When a force is applied behind the plane by the engine, the plane moves forward - wheels still on the ground but moving faster. The treadmill speeds up by an increasing force supplied to it. But none of this increased force is applied to the plane because the coefficient of friction for the wheels has already been overcome. Is this it?

If so, double check this assertion. The roller skates and rope on a treadmill test calls for me to be able to pull myself forward at a specified rate (x mph) using the same amount of pulling force no matter how fast the treadmill is turning - again because once the coefficient of friction in the skates' wheels is overcome, all additional force applied to the wheels is dissipated in the wheel and is never transfered to the load.

Is this the rationale?

[sputnik]

Yes, that's pretty much it. Jeff gets a beer.

[BEC]

Man, I made one little post to this thread back on page 26 thinking it would make a nice "thread ender" and look what happened.  8 more pages now.

Bob

[sputnik]

Yeah Bob. This was all your fault. Now Jeff and I will have to double bill all of our clients today to make up for yesterday.

[Jeff Matthews]

Yes, that's pretty much it. Jeff gets a beer.

See? I get a beer for all that. What's to be embarrassed about? Knowledge, plus a beer! It's all good! [Y]

[oldtimer]

New guy buys the beer for everyone else, Jeff. Shall I send you my address for that case of Shiner?

[Jeff Matthews]

The rule is we have to drink together. When you're in H-town, give me a holler. Beer's on me.

[oldtimer]

Roger that!

[pauln]

In a frictionless environment, a fly could bump into the plane and send it off at the speed of light - never to stop again.

In this one sentence you reveal that that you are clueless about friction, force, impact, mass, inertia, velocity, acceleration, much less special relativity (since the plane is not accelerating in its reference frame prior to the fly impact).

Jeff, you have no understabding of physics whatsoever. In order to discuss physical ideas you must know the meaning of the words and understand the concepts. You are thinking in a mode that uses words to make a demonstration, but it doesn't work that way in science and has been out of serious use since the Dark Ages - recall the Monty Python segment about the witch (Will she float?).

[Jeff Matthews]

In a frictionless environment, a fly could bump into the plane and send it off at the speed of light - never to stop again.

In this one sentence you reveal that that you are clueless about friction, force, impact, mass, inertia, velocity, acceleration, much less special relativity (since the plane is not accelerating in its reference frame prior to the fly impact).

Jeff, you have no understabding of physics whatsoever. In order to discuss physical ideas you must know the meaning of the words and understand the concepts. You are thinking in a mode that uses words to make a demonstration, but it doesn't work that way in science and has been out of serious use since the Dark Ages - recall the Monty Python segment about the witch (Will she float?).

Well, now, Paul, you just couldn't let it die, could you? If you apply a force to an object in a frictionless environment, what happens? Since you are "quite-the-physicist," Let's apply 10 newtons to a 5 kg mass. Show me the formula, with all the math.

[oldtimer]

Do you really want to know Jeff? Yes, he's right about the literal ridiculousness of the statement, but I for one did not take you literally. Did I give you more credit than was due?

[oldtimer]

For example, check out this link for broad overview of something as simple as option pricing. Keep in mind this is the basic idea, without each component broken down into it's own formula.

http://en.wikipedia.org/wiki/Black-Scholes#Derivation_and_solution

Simple right? LOL.

[Jeff Matthews]

Do you really want to know Jeff? Yes, he's right about the literal ridiculousness of the statement, but I for one did not take you literally. Did I give you more credit than was due?

Yeah, Oldie, I really want to know. It may be a literally ridiculous statement, but I saw a similar statement while researching this jet issue. I recall when I took physics many years ago that there were alot of seemingly absurd nuances in physics that you don't think about - such as the ground pushes against a car.

I took the statement at face value with the idea being that if there is no friction to stop an object once it starts in motion, it will move forever. I know that is not exactly the statement made, so I'd like to know what happens in the example I posted. Somebody here who recalls all those formulas might certainly be able to show the math.

[Jeff Matthews]

For example, check out this link for broad overview of something as simple as option pricing. Keep in mind this is the basic idea, without each component broken down into it's own formula.

http://en.wikipedia.org/wiki/Black-Scholes#Derivation_and_solution

Simple right? LOL.

I glanced, but "no thanks." I took lots and lots of math and science, finance and statistics back in high school and college. It was really my forte at that time. I made A's in every math, science, finance and statistics course, including calculous and physics. These types of courses got me into UT Law. But like all things that don't get used over time, they go stale. I am just glad to know that there are principles that exist in these areas that I could find if I needed to. It at least helps to know they exist. Kind of like forgetting case names in the law, but remembering hearing something about the issue at hand back in law school. Then, you research.

[oldtimer]

OK, you probably would understand it then, but don't care. But you took physics (way more than I) and yet need to be shown the solution to your question? Plus you made the statement in the first place which you must have known to be ridiculous? Now you want pauln to show you an answer just to make him work? I think there is a personal conflict at work here.

[Jeff Matthews]

Oldie, as I said I took physics, but I don't remember all that stuff. So, of course, I'd need to be shown solutions. Sure, I made the statement in the first place, accepting that the person who I cited was right. It could be wrong. Paul says it is. I am not saying it is not. But if Paul was to show me so that I'll agree with him, I'm all ears. If Paul doesn't want to do that, it's fine, too. No skin off my back either way. I'm not trying to provoke anyone into doing anything nonsensical just for my amusement.

It's like this. If you state something you think is the law, such as "oral contracts are not enforceable." I can tell you that you are wrong. You may have even had a little business law years back, and still made that comment. It doesn't mean you are trying to make me spin my wheels to explain for no reason at all. See what I mean?

[Jeff Matthews]

OK, you probably would understand it then, but don't care. But you took physics (way more than I) and yet need to be shown the solution to your question? Plus you made the statement in the first place which you must have known to be ridiculous? Now you want pauln to show you an answer just to make him work? I think there is a personal conflict at work here.

Oldie, you think I could just look at that math with a few paragraphs of instruction and understand it? Not on your life! I think you'd have to sit down with me for probably a couple of hours to get a good grasp on what is going on with the formulas to which you linked. Sure, I could be a monkey and plug numbers into an equation even though I don't know how the equation was derived. But if you want me to understand, it will take a little educating me, for sure.

[oldtimer]

Yeah I see what you mean. One of these days, very possibly in the next 3 to 6 months I will be in Houston and would enjoy meeting you face to face. As far as the math to your question I can't help, but I can understand why bumping a mass the size of a plane in space (practically and as close as we can imagine to frictionless) with a smaller mass will not send the larger mass off at the speed of light. It will alter its course perhaps. If it was going the speed of light it would also be slowed down. If it was stationary the plane would then move in a direction and not stop until it hit something else large enough to stop it. Even if the fly was at the speed of light the plane would not then reach light speed as a result of collision. Obviously I am not a physicist and use words like you to explain a point. BTW, some witches float, and some don't Pauln.

Edit: I will not go into Black-Scholes when in Houston, just as you will not regale me with case law!

[Ray Garrison]

Do you really want to know Jeff? Yes, he's right about the literal ridiculousness of the statement, but I for one did not take you literally. Did I give you more credit than was due?

Yeah, Oldie, I really want to know. It may be a literally ridiculous statement, but I saw a similar statement while researching this jet issue. I recall when I took physics many years ago that there were alot of seemingly absurd nuances in physics that you don't think about - such as the ground pushes against a car.

I took the statement at face value with the idea being that if there is no friction to stop an object once it starts in motion, it will move forever. I know that is not exactly the statement made, so I'd like to know what happens in the example I posted. Somebody here who recalls all those formulas might certainly be able to show the math.

Relatavistic effects aside, it's pretty simple. An object's velocity is defined as a change in position over time. Changes in velocity result from acceleration. Specifically, an object's velocity at any time "T" is given by the sum of its initial velocity plus the rate of acceleration times the time during which it has been accelerating. That is, Vt = Vo + aT. An object with an initial velocity of 0 m/s accelerating at 10 m/s for 5 seconds will be traveling at 50 m/s at the end of that time. If the acceleration is removed at that point (we run out of gas) and we are in a frictionless environment (as you stated) the object will continue to move at 50 m/s indefinately.

The rate of acceleration is determined by the formula Force = Mass X Acceleration, or Force / Mass = Acceleration. If we apply a force of 1 Newton (one kilogram meter per second per second) to a 2 kilogram mass, it will begin to accelerate at a rate of 0.5 meters per second per second.

If relativity were not a factor, any acceleration applied continuously to a mass would continue to accelerate that mass without bound. Given a sufficient amount of time during which the acceleration was applied, the mass could attain any specific finite velocity. This is pretty much true for most things we interact with (planes, cars, guns, baseballs) because the velocities are so low compared to the velocity of light ©. The proportional amount of relativistic effects can be approximated by dividing something (mass, in this case) by the term (1 - (v^2 / c^2)) (that is, one minus (velocity squared divided by the speed of light squared)). At any speed far below the speed of light, the v^2 / c^2 term approaches zero, so the mass is divided by (1-0), or 1. As velocity begins to approach c, this term begins to take on a value that impacts the mass, increasing it. As velocity begins to approach c, mass begins to increase rapidly. This is important in things like partical accelerators, where the partical streams are moving at a significant portion of the velocity of light.