General Definition and 1000 Threads

Sorry if this seems like a stupid question but I cannot find an answer. I am asking this because to me, it seems like the hard part of coming up with general relativity would be discovering what gravity actually was ( the deformation of spacetime ), and the field equations and mathematics would...

How many general electives are typical for a bachelors degree in Physics? They are accepting 18 of my art credits for the Physics Transfer program at the associates level. I would like to know how many credits will count towards a bachelors. I am guessing 9 credits...I am trying to get an...

Hello There, I hope I posted this in the right thread. I've been struggling with solving this particular Differential Equation and just couldn't find any way to solve it completely.. 1. Homework Statement I am only required to find the general solution of the differential equation y'' + y' =...

Homework Statement A rocket of force 1000N is propelled upwards by a thrust of 1800N. The air resistance is 500N. a) Work out the resultant force on the rocket. A bungee jumper of mass 60kg jumps from a bridge tied to an elastic rope which becomes taut after he falls 10m. Consider the jumper...

We know that the solutions of time-independent Dirac delta potential well contain bound and scattering states: $$\psi_b(x)=\frac{\sqrt{mu}}{\hbar}e^{-\frac{mu|x|}{\hbar^2}}\text{ with energy }E_b=-\frac{mu^2}{2\hbar^2}$$ and $$ \psi_k(x)= \begin{cases} A(e^{ikx}+\frac{i\beta}{1-i\beta}e^{-ikx})...

Homework Statement [/B] http://www.dartmouth.edu/~sullivan/22files/New%20Laplace%20Transform%20Table.pdf (see item 26a) homogenous solution to underdamped in amplitude phase form: (see attached image) 2. Relevant info - non zero initial conditions: x(t=0) = xo AND dx/dt(t=0) = vo - unforced...

i'm ashamed, that i never understand this, eventhough I'm studying quantum mechanics... so... why is there "weightlessness" on the top of a verticle circular motion? ie, if a plane if flying in verticle circles, why is there weightlessness while on the top of a circular path? i mean, if it's...

Homework Statement Find the general solution to differential equation y''-6y'+9y=e^x((2x+1)\cos x+(x+3)\sin x) Homework Equations -Non homogeneous differential equation -Homogeneous differential equation with constant coefficients -Method of undetermined coefficients The Attempt at a Solution...

I'm very interesting in functions of the nature: f(x) = x^{x} f(x) = x^{x^{x}} and so on. I believe these are called tetrations? Regardless, I sought to generalize the nth derivative of f(x)=x^x and it is proving to be difficult. First I tried just repeatedly differentiating until I could...

Hello. I have 2 books in General Relativity: MTW Gravitation and Bernard Schutz First Course in General Relativity. I studied Calculus I, II, and have a basic understanding of Linear Algebra(did not studied extensively). I want to learn about GR as much as possible, and improve myself to become...

Hi, I am just confused, regarding some definition above, I hope anybody can help explain differences. Does atoms resonate when subjected to some wave?

We recently touched base with gravity in regards to general relativity and I'm a bit perplexed. So apparently (and correct me if I'm wrong) gravity is created when the mass of the universe warps, or bends, space-time. I've read all those analogies about a trampoline curving due to an object of...

Homework Statement Which of the following are not extensive functions: S[1] = (N/V)[S[0]+[C][v] ln(T) + R ln(V)] S = (N)[S[0]+[C][v] ln(T) + R ln(V/N)] S[3] = ([N])[S[0]+[C][v] ln(T) + R ln(V/N)] 2. Homework Equations I'm not really sure how to approach this problem. The definition that I...

Hi, in the book 'Introduction to Quantum Mechanics' by Griffiths, on page 71 in the section 'The Delta-Function Potential' he states that the general solution to time independent Schrodinger Equation is $$\psi(x) = Ae^{-\kappa x} + B e^{\kappa x}$$ he then notes that the first term blows up as...

I am reading John M. Lee's book: Introduction to Smooth Manifolds ... I am focused on Chapter 3: Tangent Vectors ... I need some help in fully understanding Lee's conversation on computations with tangent vectors and pushforwards ... in particular I need help with a further aspect of Lee's...

So I doubt that this suggestion is going to be taken but I'd thought I'd make it anyway: I propose the Classical Physics forum be supplanted by 3 separate forums(for classical physics): Electrodynamics, Classical Mechanics, and Fluid Dynamics. And perhaps a Thermodynamics forum if there isn't...

My friend is a 7th grade teacher and has asked for help finding resources she can share with her students. Web sites, videos, books, etc. appropriate for a Jr High/middle school level. Specific topics she'd like to cover would be: time travel economics (socialism vs capitalism - real economics...

What makes physics interesting to physics majors (ik this is kind of general)? Also how could I get interested into physics.

Hello, since gμν gμν = 4 where g = diag[1,-1,-1,-1], see: https://www.physicsforums.com/threads/questions-about-tensors-in-gr.39158/ Is the following equation correct? xμ xμ = gμνxν gμνxν = gμν gμνxν xν= 4 xμ xμ If not, where is the problem? Cheers, Adam

I'm watching a Stat. Mech. lecture and in it, the lecturer mentions a "general probability distribution" but doesn't explain what exactly that is, yet in the context of the video, everything necessary to understand is understood. On some cursory google searches I'm finding several hits for a...

I am preparing a couple questions for the Nuclear Engineering forum, about nuclear weapons. During the past few weeks, I've been reading a number of interesting articles and books, most notably "The Goldsboro Broken Arrow" by Joel Dobson, and a number of articles reported through the book and in...

"The presence of this field, now believed to be confirmed, explains why some fundamental particles have mass when based on the symmetries controlling their interactions they should be massless." (wiki) It would seem, to myself, a novice, that the Higgs field and its corresponding particle, if...

I am reading Susan Colley's book: Vector Calculus ... and am currently focussed on Section 8.1: An Introduction to Differential Forms ... ... Colley, on page 491 in Example 3 gives a formula for a general 2-form as follows:I am trying to understand what Colley describes as 'the somewhat curious...

What is the underlying feature of general relativity that, unlike Newtonian mechanics, results in the correct calculation of orbits i.e. including precession (e.g. Mercury). I not asking for the mathematics (i.e. the additional term in the equation) but rather what underlying "physical"...

Hi all, just curious. I am just learning about user-defined functions in MSSQL2014. What kind of Math can we do with it? Didn't get much useful from my search.

Hi, I am looking for the general form of 2x2 complex transformation matrix. I have the article, that says "the relative position of a self-adjoint 2x2 matrix B with respect to A as a reference (corresponding to the transformation from the eigenspaces of A to the eigenspaces of B) is determined...

Which books in QFT give representations about general proof of renormalization?I know that the book of QFT of Peskin&Schroder does not give the full demontration.

I'm looking for a nice set of basis matrices ##B_{i,j}## that cover the matrices of size ##n \times n## when linear combinations are allowed. The nice property I want them to satisfying is something like ##B_{i,j} \cdot B_{a,b} = B_{i+a, j+b}##, i.e. I want multiplication of two basis matrices...

I am having a little trouble with a problem I am trying to solve. Given three particular solutions Y1(x)= 1, Y2(x)= x and Y3(x)= x^2 Write down a general solution to the second order non homogeneous differential equation. What I have done so far is to realize if Y1,2 and 3 are solutions...

Mentor note: this discussion was split out of a different thread. The speed of light in a vacuum is constant, but what I would like some information regarding is Black Holes. Does a Black Hole increase the speed of a light photon as it is being pulled into the Event Horizon?

Just a question about the theory of solutions to differential equations? Given a second order differential equation and two particular solutions y1 and y2, what is the best way to find the general solution? i.e variation of parameters or something else

Homework Statement Show that Ccos(wt+phi) = Acos(wt)+Bsin(wt) Homework Equations Trig identity that states cos(wt+phi) = cos(wt)cos(phi)-sin(wt)sin(phi) The Attempt at a Solution Ccos(wt+phi)=(Ccos(phi))cos(wt)+(-Csin(phi))sin(wt) let A = Ccos(phi) Let B = -Csin(phi) Ccos(wt+phi) =...

Is there a general way of knowing if an elementary boson for example is virtual or real? So for example, two leptons annihilate into an elementary boson. Then you can get real photons, W+-/Z° bosons depending on the leptons. However W+-/Z° and photons can also be virtual when acting as...

Does the stress-energy tensor depend on direction of the relative velocity of two celestial bodies? Assume vy is directed parallel to the gravitational field of the planet, vx and vz are perpendicular to the field, and that the speed would be the same whichever direction it is in. Does it matter...

Hi, I'm new here and I'm trying to learn GR. I wanted to know the math books that I need to tackle GR properly, so far the books that I came across are: Tensor Analysis on Manifolds by Bishop and Goldberg Tensors, Differential Forms, and Variational Principles by Lovelock and Rund I have a good...

Not a homework problem, so not sure if this is in the right area. Thought it was too sophomore to post in the maths forums. So, when you integrate y within defined limits for x, you get the area between the graph and the x-axis within those limits for x. But a) Why is this always between the...

So far I have calculated this for a cone, which elegantly results in the conic sections. However, I would like to do this for the other quadric surfaces. Is the calculation for this been published anywhere online?

Mod note: Thread moved from HW section 1. Homework Statement My native language is not English,and I'm not good in reading hand writtings.I got a short passage on mathematics.Please tell me if you could help me with that.I've attached it as "Lif.pdf".Homework EquationsThe Attempt at a Solution

I was reading through some main stream scientific literature, and I came across Sean Caroll's "Energy Is Not Conserved" post. Essentially, he contends that through general relativity energy is not conserved, at least not in conventional manner of thinking about energy. Anyways, some portions of...

I am about to take General Physics 1 (Calculus version) in the spring and I am nervous. What is it like? Can you post an example of the kind of questions I will be given in Physics 1.

I was pondering Mars missions and wondered about what kind of vehicle an astronaut on Mars would need in order to get home. My first thought was that Mars gravity is .38 that of earth, so he would need a rocket about 38% as large to get off of Mars as he needed to get off of earth, This of...

Hi, I have 0 background in engineering nor robotics. I have a project requiring both, so if you can help at all or give good feedback that would be very appreciated. The true reason behind my project is a bit secretive for me, purely because I think it’s a smart idea and I don’t want the idea...

Hello, I'm currently enrolled in a 6 week General Chemistry 1 class that starts in January. The class meets about 5 hours a day Monday - Friday. I took the introductory chemistry course offered at my college this fall, and I was able to keep an A+ without much trouble. What can I do between now...

Hello, I'm Harry. I'm new here, hope not breaking any posting rules in any ways :) I have a question and would like to ask for some suggestions and information. The question is about general relativity or gravity and structure of the Universe in general; I know there are definitely quite a...

I understand this topic has been brought up before, however there appears to be "truth" or "lies" and very little in between when it comes to explaining the Heisenberg Uncertainty Principle (HUP) to students of freshman chemistry. I'm teaching university general chemistry to students who've had...

I've been leafing through a recently bought copy of James B Hartle's Introduction to Einstein's General Relativity and I notice that some of the questions have one or more letters assigned to them, such as A, B, C, S, P. It seems that my Pearson New International Edition does not contain the key...

I am attending college next year but I am really confused between two majors. I am interested in astronomy and my dream is to pursue my career doing astronomy and I can wait to study astronomy in college. I know that astronomy is completely physics but I am confused whether should I choose...

Given a scalar function g defined on a manifold and a curve f:λ -> xa, the change of the function along the curve is \frac{dg}{d\lambda} = \frac{dg}{dx^{a}}\frac{dx^{a}}{d\lambda} = T^{a}\frac{dg}{dx^{a}} where \frac{dx^{a}}{d\lambda} = T^{a} is the tangent to the curve. The argument that I...

I know this question has been asked by others before, but: I did poorly on the math part of the general GRE. I got a 160 (78%). I actually did better on the verbal (161, 87%)! I just ran out of time because I took too long on some problems. I did practice tests and did fine on them, but I...

…… is the splitting of light into its constituent colors (wavelengths). Can I use the term ‘dispersion’ here? Or is ‘dispersion’ only restricted to splitting due to phase velocity/refraction differences of different wavelengths (prism)? If not ‘dispersion’, is there another general term that...