JohnSSM Posted January 12, 2015 Author Posted January 12, 2015 Im also really glad that you noted that I wasnt "against" GR even in the beginning...just the goofy latex sheet...and sure, I slaughtered it all with some of my attempted explanations...but ive never tried to understand anything more than these concepts... It can be, but I feel that to make mathematics really fun it should have some applications. Not that everyone will agree with that statement. I do see that...Yknow, when i look at SOME of the equations, the math isnt that daunting at all, but all the terms! I need to know the terms...IS there a good listing of all the terms in oneplace so I can just start memorizing them? .I cant believe my computer cut and pasted that...I do not have those characters on my keyboard...alas...terms...little sub b, little sub uv...whaaa? Where Rμv is known as the Ricci curvature tensor, gμv is the metric tensor, R is the scalar curvature, Λ is the cosmological constant, G is the gravitational constant, π is pi, c is the speed of light, and Tμv is called the stress-energy tensor.They use the Cosmological constant? I thought that was the biggest blunder of his career that hubble disproved...but its in the equations still?
ajb Posted January 12, 2015 Posted January 12, 2015 I would not recommend simply trying to memorise things. The best thing to do is to use them enough so that you become familiar with them. Anyway, for general terms in mathematics and physics Wikipedia is okay, but not all the physics sections are great. Sometimes you need to be careful with some of the language they use, as you have already seen. For GR in particular I like the lecture notes by Carroll, they are free online. Or you can buy his book which is based on these notes, but further polished and extended.
Strange Posted January 12, 2015 Posted January 12, 2015 They use the Cosmological constant? I thought that was the biggest blunder of his career that hubble disproved...but its in the equations still? Einstein added the constant because it was assumed at the time that the universe was static, while GR predicted it should expand or contract. When it was confirmed that it was expanding, then it was taken out again (or rather, set to 0). When it was then found that the expansion was accelerating, it was reintroduced (with a value set by the observed rate of acceleration).
JohnSSM Posted January 12, 2015 Author Posted January 12, 2015 The lecture notes by Carroll are one of the "books" i'm reading right now...I love the first line in the GRAVITY section,,,,"Now that we have paid our mathematical dues...etc"and I thought...I am going to have to pay my mathematical dues cuz im not getting this...but still a good read so far Einstein added the constant because it was assumed at the time that the universe was static, while GR predicted it should expand or contract. When it was confirmed that it was expanding, then it was taken out again (or rather, set to 0). When it was then found that the expansion was accelerating, it was reintroduced (with a value set by the observed rate of acceleration). Wow...awesome info...thats pretty wacky!
Strange Posted January 12, 2015 Posted January 12, 2015 Wow...awesome info...thats pretty wacky! That's science!
JohnSSM Posted January 12, 2015 Author Posted January 12, 2015 That's science! It kinda shows that every once in a while a real observational finding is made that does demand a need to change...but when most of the findings still show that it needs to stay the same, you wouldnt scrap the entire model...i think i get it... When I think of all the success ive had in "doing it myyyyyy way" as Sinatra would say, this just isnt that type of study... When I look at the backwards approach I often take to many things, I was starting off with my own "models" and adjusting them as I find evidence that suggests that I must...its pretty much what I did here in this topic...I made up this notion of space foam so I could have something to shape in my mind...and I shaped that "model" according to what I was learning from people who KNEW or had the BEST INFO about what is true...yes, always with mathematical proof...I didnt have to have it, THEY did...and I could mold my interpretation of what they were saying and adjust the way my foam acted...i constructed it's properties from the realities that I thought they were finding...It was my journey...I suppose that IF it could make ANY sense to anyone with real knowledge, it would validate my process to any degree...i didnt need totality of truth...Just trying to see how close I came with some of my estimations and such... I was and still am very grateful when someone listens and acknowledges...and I still get a bit poopy when someone suggests there is nothing behind what Im expressing.... I dont have a different way to share, but here is a facebook link to my 2d graphic representation of Spacetime foam with object of mass at center https://www.facebook.com/photo.php?fbid=1523304897958045&set=a.1399707273651142.1073741829.100008356482793&type=1&theater and an improved version... https://www.facebook.com/photo.php?fbid=1523319187956616&set=a.1399707273651142.1073741829.100008356482793&type=1&theater Best and final version... https://www.facebook.com/photo.php?fbid=1523323271289541&set=a.1399707273651142.1073741829.100008356482793&type=1&theater And here is my rendering of a mass in motion in the direction of the arrow. https://www.facebook.com/photo.php?fbid=1523336581288210&set=a.1399707273651142.1073741829.100008356482793&type=1&theater
elfmotat Posted January 12, 2015 Posted January 12, 2015 (edited) I do see that...Yknow, when i look at SOME of the equations, the math isnt that daunting at all, but all the terms! I need to know the terms...IS there a good listing of all the terms in oneplace so I can just start memorizing them? . Terms are not so important. Knowing the name of something is not the same as knowing something. (Another Feynman video.) You'll learn the terms over time, in their proper context, by reading textbooks or lecture notes -- the same way you learn interesting vocabulary words by reading books. Memorizing things is almost always a bad idea, as it does not really contribute to any meaningful understanding. What's important is understanding the math, what it means, and how to extract information from it. For example, the equation you posted above is a statement of local energy-momentum conservation. It means that energy/momentum cannot be locally created or destroyed. Edited January 12, 2015 by elfmotat
Mordred Posted January 12, 2015 Posted January 12, 2015 As far as posting the math to get assistance etc. You will want to learn latex. Here is this forums guide on that. http://www.scienceforums.net/topic/3751-quick-latex-tutorial/#
JohnSSM Posted January 13, 2015 Author Posted January 13, 2015 Terms are not so important. Knowing the name of something is not the same as knowing something. (Another Feynman video.) You'll learn the terms over time, in their proper context, by reading textbooks or lecture notes -- the same way you learn interesting vocabulary words by reading books. Memorizing things is almost always a bad idea, as it does not really contribute to any meaningful understanding. What's important is understanding the math, what it means, and how to extract information from it. For example, the equation you posted above is a statement of local energy-momentum conservation. It means that energy/momentum cannot be locally created or destroyed. Feynman could definitely use words to convey concepts...Ive watched just about every feynman video on youtube... In one of them, wearing no shoes, he explains probability and had me grasping it ways I never considered....he is an eye opener... As far as posting the math to get assistance etc. You will want to learn latex. Here is this forums guide on that. http://www.scienceforums.net/topic/3751-quick-latex-tutorial/# Eh, ive allready got a dominatrix,,,not the same?
Mordred Posted January 13, 2015 Posted January 13, 2015 Lol latex is the syntax to post math equations Instead of F=GM/r^2 If you use latex you get [latex]f=\frac{GM}{r^2}[/latex] The guide will step you through how to use the syntax. Just like that formula you cut and pasted in your earlier thread. Like the dominatrix joke though
JohnSSM Posted January 13, 2015 Author Posted January 13, 2015 I did take a good look at the post...definitely need to review it i length...but yeah...just some tools to begin with this stuff are great Do you all think they will let me make another topic in "classical physics" about the "golf ball spin" idea I was inquiring about earler in this topic?
Mordred Posted January 13, 2015 Posted January 13, 2015 If you post it as a specific question and set of relations of influence. Probably. Your now trying to understand GR specifically so I don't see why not. Keep the post specific to understanding the GR metrics rather than your own model ideas. Your golf balls is an exercise is the conservation of angular momentum.
JohnSSM Posted January 13, 2015 Author Posted January 13, 2015 If you post it as a specific question and set of relations of influence. Probably. Your now trying to understand GR specifically so I don't see why not. Keep the post specific to understanding the GR metrics rather than your own model ideas. Your golf balls is an exercise is the conservation of angular momentum. But you dont even need GR to talk about golf ball impacts...So, where to post it. is in question...Classical Physics or Relativity...seems classical physics would be the best fit...ill try it My rationing is, Couldnt Newton tell us everything we know about the physics of golf? Did GR effect those types of things? I know that GR could it explain it, but i was hoping to talking out it in terms of, angle of impact, conservation of energy and spin...
Mordred Posted January 13, 2015 Posted January 13, 2015 (edited) Classical physics covers the angular momentum laws GR simply conforms to it. Frame dragging of space time is where GR kicks in. The rest is explained in the classic models Edited January 13, 2015 by Mordred
JohnSSM Posted January 13, 2015 Author Posted January 13, 2015 (edited) Wow...I found it...but I wont be understanding this much sooner than GR anyway...http://www.real-world-physics-problems.com/physics-of-a-golf-swing.html Edited January 13, 2015 by JohnSSM
Mordred Posted January 13, 2015 Posted January 13, 2015 Lol lot of differential geometry and trigonometry involved.
JohnSSM Posted January 13, 2015 Author Posted January 13, 2015 So, I have these questions that need to be answered (for my own reasoning) and the math has allready been done to get the answers...Like..If you hit a gold ball "straight on"...i know that implies so much i terms of a swinging club.But is there an angle for which you can make contact (a vector?) which will only send the ball in the exact direction from which the force was applied?The answer to the question has been figured and resides as a mathematical truth now...I just need the answer...I get to use GPS all the time without knowing GR... Once again, im asking for fish without learning to fish...But just imagine that everytime you started to cook, someone demanded you know the physics of heat before you asked at what temperature to cook your pork chops... Am i just being lazy when I buy ziplock bags instead of making them myself? ie "You dont deserve to have and use that ziplock bag because you dont undertand it's nature!" No zip lock bags for you!
Mordred Posted January 13, 2015 Posted January 13, 2015 (edited) Try something similar look at when you hit a ball on a pool table. If you hit the cue ball straight on without spin on the cue if it hits straight on the next ball it moves straight. Now if you hit an edge of the second ball the angle of deflection opposite to the surface of impact. Ie if you hit the ball at 5 o clock it will head to 11 o clock If you convert that to degrees ball will move 180 degrees from point of impact. Now say the second ball is hitting the rail on a bank shot. In this case measure the angle in the angle out will be the same (provided no spin is introduced). Here is a free vector calculus book to help study http://www.google.ca/url?sa=t&source=web&cd=1&ved=0CBsQFjAA&url=http%3A%2F%2Fwww.mecmath.net%2Fcalc3book.pdf&rct=j&q=vector%20calculus%20pdf&ei=toC0VIfCEIaoogS104KoCA&usg=AFQjCNHaZioCHqqCO924EPbzoMQrUS2fIg&sig2=uAzhUQQ0eu4MpH9HM78yyg&bvm=bv.83339334,d.eXY Pool is a good game to understand angles of deflection. Keep in mind in the first example you will induce a spin on the second ball. Edited January 13, 2015 by Mordred
StringJunky Posted January 13, 2015 Posted January 13, 2015 ...Once again, im asking for fish without learning to fish... You want to know everything but understand nothing?
JohnSSM Posted January 13, 2015 Author Posted January 13, 2015 (edited) You want to know everything but understand nothing? No...once i have the ziplock bag I still need to learn how to use it...and in using it, I learn about it... and then i can tell the next person without fail "You cannot use that bag to hold battery acid, nor can you fill it past this pressure and expect it to stay zipped...So i dont know everything, but i do learn what i need to know... When you turn on your computer, do you want to know everything but understand nothing? This may not apply to you, but most folks have no idea how to make a computer and can still use it very very well...and they do learn and understand it...on different terms than creating it... I think the solution lays in me offering payment for answers...in the cases of specific questions anyway...I understand the method that yall as experts and moderators have used for addressing such questions...and its probably the same rules that every forum comes up with if they have any organization at all...This is where the logic tends to go... But yall just sit around waiting for me to say something to attack...when i am right, I rarely hear, you are right...you tell me to prove to you that am right...and after that lengthy process, i get to move on... If we were trying to tow a car with a shoestring, i wouldnt make you prove how and why the shoestring will break if we try...is that how you live and make your way? Im not trying to offend anyone...truly...its just a perspective... Id rather be going back and forth about golf ball spin, but to drive the point home, Mordred even refused to discuss it in my terms...he made new terms with a pool table...fellas...I get it...Ill stop until I have questions about math,,, But you could just say "We will not discuss these things in any terms with you besides math, ever." Then i never would have gone there... Because Im very observant, I figured the approach...it might confuse others to your actual intentions which aren't confusing or mean, they just come off that way unless you explain them... Edited January 13, 2015 by JohnSSM
StringJunky Posted January 13, 2015 Posted January 13, 2015 No...once i have the ziplock bag I still need to learn how to use it...and in using it, I learn about it... and then i can tell the next person without fail "You cannot use that bag to hold battery acid, nor can you fill it past this pressure and expect it to stay zipped...So i dont know everything, but i do learn what i need to know... When you turn on your computer, do you want to know everything but understand nothing? This may not apply to you, but most folks have no idea how to make a computer and can still use it very very well...and they do learn and understand it...on different terms than creating it... I think the solution lays in me offering payment for answers...in the cases of specific questions anyway...I understand the method that yall as experts and moderators have used for addressing such questions...and its probably the same rules that every forum comes up with if they have any organization at all...This is where the logic tends to go... But yall just sit around waiting for me to say something to attack...when i am right, I rarely hear, you are right...you tell me to prove to you that am right...and after that lengthy process, i get to move on... If we were trying to tow a car with a shoestring, i wouldnt make you prove how and why the shoestring will break if we try...is that how you live and make your way? John, what I said was with the sincerest of positive intentions towards you. I've spent five years on here, just skimming the maths without really getting a handle on it. I've got the general picture but I can't alter or really understand what makes up the the picture because I haven't got the required techniques to make them myself. I acknowledge that one cannot be scientifically creative without understanding it's core language; maths. I fear the path you are trying to take - just looking for answers - will ultimately be deeply unsatisfying. 2
Mordred Posted January 13, 2015 Posted January 13, 2015 The pool table Is easier to understand angles of deflection spin and how the laws of inertia apply to the conservation of angular momentum. The math involved Is easier to calculate as involve less sources of force. In the golf ball you have the force of the swing the centripical acceleration of the end of the golf club force of gravity to add. In pool you just have the force applied to the pool cue. Which one would you like to start off on? The harder problem first or The easier problem set ?
JohnSSM Posted January 13, 2015 Author Posted January 13, 2015 John, what I said was with the sincerest of positive intentions towards you. I've spent five years on here, just skimming the maths without really getting a handle on it. I've got the general picture but I can't alter or really understand what makes up the the picture because I haven't got the required techniques to make them myself. I acknowledge that one cannot be scientifically creative without understanding it's core language; maths. I fear the path you are trying to take - just looking for answers - will ultimately be deeply unsatisfying. Fer sure...I just like to make a point when I make it ...or try...don't take that effort as aggression, please...two different models of energy! The pool table Is easier to understand angles of deflection spin and how the laws of inertia apply to the conservation of angular momentum. The math involved Is easier to calculate as involve less sources of force. In the golf ball you have the force of the swing the centripical acceleration of the end of the golf club force of gravity to add. In pool you just have the force applied to the pool cue. Which one would you like to start off on? The harder problem first or The easier problem set ? I totally see how the pool table is easier, there is much less happening... But im asking about the moment of impact...an event horizon...at that moment, all the physics it took to get there dont matter...we have an impact with direction and force....if we do this in a vacuum, are there any other forces effecting that reaction? Lets just make it one square block hitting another square block...If one block impacts another "straight on" while neither object is spinning, will any spin be transferred between the two blocks? sorry for changing the terms once again, but i thought pool is easier than golf, but two square blocks seem to offer a very easy model...
Mordred Posted January 13, 2015 Posted January 13, 2015 No head on in the non rotating BH case no spin is induced. For a rotating BH yes. This is due to the frame dragged space time path
JohnSSM Posted January 13, 2015 Author Posted January 13, 2015 No head on in the non rotating BH case no spin is induced. For a rotating BH yes. This is due to the frame dragged space time path Ha...ok...so you can stop pretending that you dont know the game im playing too...
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