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Yeah, psikey, carry on.
Good to see you again, Fallenangel. Am I correct in my recollection that you were studying the last time you popped in? Physics? Gnarly physics, I believe. How's it going?
Sounds quite fascinating and way way over my head....Orientation Bias in Galaxy Cluster Mass Measurement...
So what exactly N-body simulations simulate then?!? You know the ones that rely on a mathematical representation of particles interaction through gravity...
Fallen.
You said it... a mathematical representation of gravity is not gravity. In reality can you change the strength of gravity by just changing numbers in a computer program?
psik
ROFLMAO
There is no gravity in SIMULATED physics. The acceleration vector has to be computed and applied to the simulated mass. No SUPPORT is required.
What is your problem Dorman? Even I know you are smarter than that! Or can you copy the code from my program for these weightless connections you are imagining.
psik
Sounds quite fascinating and way way over my head.
psikey, could you give this nice young person some advice and instruction on potential energy?
Nice try there mate...but you've specifically stated the following in red.
...so... yes there is gravity in simulated physics, as one can simulate gravitational interaction between objects of different or similar mass.
PS. Just for laughs, how else you propose to quantitatively describe objects and the interaction between them besides using math?!? As according to your last statement for example "mathematical representation of an angle is not an angle".
Fallen.
ROFLMAO
There is no gravity in SIMULATED physics. The acceleration vector has to be computed and applied to the simulated mass. No SUPPORT is required.
What is your problem Dorman? Even I know you are smarter than that! Or can you copy the code from my program for these weightless connections you are imagining.
psik
...and yet you've specifically claimed the following:
...which is false, as gravitational interaction can be simulated in simulations as the other parts of ones simulation.
You can try and mask your ignorance with rational wiki links and attempts at pseudo-logical arguments, yet, your original claim will still be false.
PS. So how about that non mathematical quantitative representation of a concept, got any suggestions?!?
Yeah, psikey, carry on.
A simulation of gravity is not gravity. The map is not the territory just like I said.
A simulation is merely useful and informative if it is sufficiently accurate. But it is not reality.
So part of our problem with 9/11 is "experts" not demanding accurate data about the towers. How can worthwhile simulations be made without that information. You can believe I am masking ignorance all you want. Where are the physical models and simulations of the north tower collapse? I don'tknow anything about satisfactory ones. :roll:
psik
ROFLMAO
There is no gravity in SIMULATED physics. The acceleration vector has to be computed and applied to the simulated mass. No SUPPORT is required.
What is your problem Dorman? Even I know you are smarter than that! Or can you copy the code from my program for these weightless connections you are imagining.
psik
The concepts aren't really that hard, we've done something similar to this: https://arxiv.org/abs/1405.0284I see, maybe not as involved as I thought, but definitely heady stuff. Remember you're now looking at these things through the lens of expert. Feels good, doesn't it?
I commend you for trying with psikeyhackr... I think. Definitely sorry for the dirty trick of turning him on you. It's okay; click the 'x' button in the upper right of your browser window and >poof< he goes away.
I think I've still got the record for most posts responding to psik.I commend you for trying with psikeyhackr... I think.
Sure I can. They're the "magic supports".Apparently you can't by specifying any massless connections in my code. :lol:
psik
psikeyhackr said:In each case four masses are magically suspended and when struck from above each mass is released with no resistance.
psikeyhackr said:This could only happen in a computer with masses held up by “magic”.
psikeyhackr said:It is a magical collapse in that the masses are held up without supports until they are struck from above...
psikeyhackr said:This could only happen in a computer with masses held up by "magic".
(Note masses which do not fall in a gravitational field ARE supported, even implicitly)psikeyhackr said:But I also did a Python program with magical floating masses and no supports.
WOOOOO! This thing that you've heckled me for so much is STANDARD OPERATING PROCEDURE in professional and research grade physics and simulation software.
In YOUR program (and my analytic programs), yes. If you wanted to do the same thing in off-the-shelf software, you'd have no choice but to supply a support element because gravity would affect your mass.The acceleration vector has to be computed and applied to the simulated mass. No SUPPORT is required.
In the past, you've said that ignoring the mass of the spring (support) is okay if the mass of the spring is small compared to the mass of what it supports.
The mass of the largest columns in the towers - at the bottom - is neglible compared to the mass of the entire tower above, which they support.
Small is whatever is too small to affect the result significantly, rather than some fixed ratio. But practically speaking, all of the numbers you list will be small enough for most problems. Even 10% can be small enough for some problems. Depends on the problem.What is "small"? 1%? 0.1% 0.001%?
Yes, I suppose. Sort of like knowing if a driver was wearing a wristwatch when hitting a wall at 90mph will help determine how badly the car will be crushed. The watch has mass, you know.If we had accurate data on the amount of steel and concrete on every level then we could do a better job of deciding what was and was not small.
Very small, just like the weight of the WTC columns relative to the load they held. Why keep focusing on the parachute lines, though, after seeing all of the other examples I've posted? There's a ****ing restaurant on top of a MASSLESS rod.You said NASA treated the lines on a parachute as massless in one of their simulations. What was the weight of the lines relative to the load on the parachute?
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