Path Definition and 1000 Threads

One more question: it appears that portions of the universe are expanding away from us faster than the speed of light. Given this, particles in two 'parts' of the universe that are no longer causally connected should not be able to influence each other (due to speed of light constraint). So...

I’m a Master’s student in math at a Canadian university. I am in a dilemma where I cannot decide which career path to choose. I have a very deep interest in math and computer science, but I am not sure if I want to dedicate my life to a research based job in that field. I have participated in...

In general, ##\displaystyle{\langle q_{f}|e^{-iHt/\hbar}|q_{i}\rangle=\int\mathcal{D}q(t)\ e^{iS[q]/\hbar}}## and ##\displaystyle{\langle q_{f}|\hat{Q}(t)|q_{i}\rangle=\int\mathcal{D}q(t)\ e^{iS[q]/\hbar}}\ q(t).##How can one switch from the above expressions to the following...

How does the path integral formulation of quantum mechanics as given by ##\langle q_{f}|e^{-iHt/\hbar}|q_{i}\rangle = \int \mathcal{D}q(t)\ e^{iS[q]/\hbar}## make manifest aspects of quantum mechanics such as symmetries?

I was looking at the diagrams from the lhc of the path of particles and notice that the path of the particles always craved parabolically not traveled strat outward from the point of impact. Why does this happen explachely when the particles are traveling at near light speeds thank you ahead...

Hello,I had a discussion with my professor. He tried to convince me but I couldn't understand the idea. The Stokes Theorem (Curl Theorem) is the following: My professor says that the value of the equation should be zero whenever the area of integration is closed! (which will make a volume in...

Homework Statement Homework Equations s=r* theta The Attempt at a Solution

Homework Statement Homework Equations s= r* theta 1/2 mv^2 = mgh energy conservation The Attempt at a Solution [/B] I think I might be having something wrong in the attempt. And how do you do using the polar coordinate approach?

Homework Statement Log A weighs 20Kg is laid on a diagonal smooth plane with a diagonal angle of 27 37 degree, log A is tied by a rope to the head of the plane and there through a wheel with no friction the rope descend vertically to the bottom of the plane and through another friction-less...

For line integrals in vector calculus, \int^a_b F \cdot dl I almost always see the path oriented from a to b. But my textbook has the following (look at the first equation for V(r): Since the integral's limits are from O to r, I would have expected dl to also be pointing in the direction...

So I'm really interested in orbital mechanics. I'm only 16 so my knowledge of physics is restricted to an intermediate level. If there is a planet with large mass and a planet with small mass they are attracted to each other... So imagine a system where the large mass is fixed and the small...

I know that aerospace engineering is a branch of mechanical engineering, and as a student of mechanical engineering myself, I'm curious to know what kind of knowledge a MechE coming out of a Bachelor's Degree should have if he wants to start working with aircraft (or pursuing a Master's Degree...

An nucleus of an atom is really surrounded by circular orbits or not. And why there is a pattern that orbit k can contain only two electrons, orbit l can contain only 8 electrons and so on. But at some places I observe that the nucleus of an atom is surrounded by cloud like structure containing...

I've seen several online sun path calculator like this one: http://keisan.casio.com/exec/system/1224682277 I'm wondering just how accurate are these tools? the tool above can even produce results for year 2099. is this possible? I mean, is there no possibility that these might change in the...

Recently I have reviewed by reference books to get a better understanding of the fundamentals of QFT and there is one thing I still do not understand. In the QFT derivation of the path integral formula, it seems that every book and online resource makes the assumption that for the field operator...

Hi PhysicsForums! I'm a game developer planning a project involving simplified, idealized orbital mechanics. I made this reddit post which did not generate the sort of response I was hoping for, but it summarizes my issue in greater detail for anyone curious...

Homework Statement A double slit apparatus is held 1.2 m from a screen. (a) When red light (λ = 600 nm) is sent through the double slit, the interference pattern on the screen shows a distance of 12.5 cm between the first and tenth dark fringes. What is the separation of the slits? (b) What...

Ok. I get that objects seem to fall because of curved spacetime, when they're actually just moving in straight paths. I get the example of ants walking in straight lines on the surface of a sphere, thinking that something attracts them to each other. What I don't get is how the "ants" are...

It is customary, when discussing a particle's motion through spacetime, to talk about its path x^{\mu}(\lambda) , where x^{\mu} are the the spacetime coordinates of the particle in some frame, and \lambda is some parameter. I have a doubt regarding this parameter. Everywhere I've looked...

Homework Statement [/B] Homework EquationsThe Attempt at a Solution Honestly speaking , I have little idea about this problem . All I can think of is that since the particle is in static equilibrium , the particle has no acceleration . So , if T is the tension in the string then resolving...

Trying to accomplish a monte carlo simulation on the condensed state of 4He, yet I am in my sophomore year and know only a bit of quantum statistical physics. Is there any documentations recommended for beginners to the algorithm applied to 4He? I've found some but they are not friendly to...

I'm now at my sophomore year in college, studying Mechanical Engineering. When I chose this field, I was interested in things like aircrafts and my main goal was working in the aerospace industry. This interest has shifted towards control systems/robotics since then. I started dealing with...

Homework Statement Charged pion with average life time $$\tau=10^{-8} sec$$, and mean free path in the water$$\ell=100m$$ falls prependicular to a lake (depth of lake is at $$\ell_0 =30m$$ with velocity $$V=0.9999c$$ What of the next is correct? 1). The particle isn't gona touch the bottom of...

Is there a short path to becoming a nuclear engineer if you have a B.S in physics? Can you get into grad school and specialize in nuclear engineering?

So I've heard from multiple sources that one explanation for why light slows down whilst traveling through mediums other than a vacuum is that the light "takes every possible path at the same time" through the medium. Below I've drawn my two possible interpretations of what that means. Can...

Homework Statement If an object moves with non-zero, constant accelerations in two dimensions which are equal in magnitude, its path is 1) linear 2) hyperbolic 3) elliptical 4) parabolic 5) circular Homework Equations no equations The Attempt at a Solution apparently, the correct answer...

Consider the path of a proton at 7 TeV Ke at LHC. Wikipedia says: Length contraction is the phenomenon of a decrease in length of an object as measured by an observer which is traveling at any non-zero velocity relative to the object. This contraction (more formally called Lorentz contraction...

Homework Statement Hi everybody! I'm really struggling with those exercises from my special relativity class, and I'd like to know what you think about that one because I come up with a strange result: The motion of a point mass in a plane is given by: x = a cos(ωt), y = b sin(ωt) Calculate...

Homework Statement A projectile of mass m is launched with an initial velocity [PLAIN]https://www.webassign.net/images/boldv.gifi making an angle θ with the horizontal as shown below. The projectile moves in the gravitational field of the Earth. Find the angular momentum of the projectile...

Hello people, I am currently in my third year of Physics B.Sc., and I will prospectively get the B.Sc. Degree in half a year...if I just knew in which direction to go. I wonder if it I can get into cognitive science and machine learning from that position. Which physics bachelor theses do build...

Homework Statement A right circular cylinder of ##4## cm (inner) radius and ##19.9## cm (inner) length contains ##4 \times 10^{14}## Argon atoms (atomic number ##18##). The cylinder is maintained at room temperature, nominally ##300## K. (a) Estimate the momentum transfer per square meter per...

Homework Statement I can't understand the concept of internal path length. I can't understand what this value mean in the tree? For instance if a IPL of a tree is 30 then what does it mean for the tree. Tree does not have 30 nodes so what the path length means? Li is the number of nodes in...

Homework Statement Homework Equations Find the path of a particle. What is the general or fundamental way to solve this type of questions ? The Attempt at a Solution I don't know where do i start. I can't able to find a relation between these vectors.

Hi There. I want to ask a question, here it is :- How to find the path of a particle if initial velocity(vector) is given and constant force(vector) acts on the particle. Like :- 1) How can we determine the path will be PARABOLIC 2) How can we determine the path will be CIRCULAR. 3) How can we...

Homework Statement Hi,I am trying to understand the proof attached. My problem is shown by a red arrow.Can someone explain those 2 steps? And please answer it as simply as you can...Since I haven't done multivariable calculus..It is a physics course.Thanks Homework EquationsThe Attempt at a...

Homework Statement A 0.5 kg ball is swung in a circular path from a 80 cm long rope, attached to a vertical pole. A. What is the speed of the ball theta (between the pole and rope) is 40 deg? B. What is the KE of the ball at theta = 40 deg? C. The ball slows down and the KE drops to 50% of the...

The school I plan to attend does not have a physics major. However, it has a chemistry major, as well as applied mathematics, general mathematics, and theoretical mathematics majors. It also has a physics minor. My question is this: With a double major in chemistry and applied math (or even...

Hello, I've read a few of the responses in the guidance section on this site and had some conversations with guidance personnel at my college, but I was hoping to get some other, potentially more objective insights from the group here. I will be 34 this year and am currently a sophomore at a...

If a plane has to fly across latitudes as opposed to flying across longitudes, there's also rotational motion of the earth, so if it flies from antarctica to siberia and it takes too long, it is in no way certain whether it lands in siberia, norway or Canada, so it must constantly need to move a...

Homework Statement I am only currently in multivariate calculus, so i haven't even touched differential geometry yet, but a question that i had while learning about gradients came up and it led me to the topic of geodesics and differential geometry, so here goes: Class problem: Find the...

Suppose I have a arbitrary path X(u) for u∈[0,1] of length L. I want to traverse the path at a variable speed (I'm only really concerned about the magnitude of velocity). I want the graph of my speed function σ(t) to have the shape of a sigmoid and I want it to start at an arbitrary value s0...

Homework Statement I know that at 18,000 ft. above mean sea level, the atm. pressure ~half of what it is at seal level (760 Torr). The temperature also decreases by 70C. a. How would this change the speed distribution of the air molecules quanitatively? b.How would it change the mean free...

Hello. I am a 24 yr old male who dropped out of HS in 9th grade i was young and dumb and all about partying at that time. Currently I am in school at PennFoster doing the online High School they offer in order to earn my High school Diploma then am going to college for physics chemistry biology...

Hi, I wish to not only learn, but prove every theory I come across. This requires a ton of math research, and at this point, I am about to begin quantum mechanics, and general relativity after I finish up my differential geometry book. My question, I suppose, is after I finish differential...

Homework Statement In a Young’s two-slit experiment a piece of glass with an index of refraction and a thickness is placed in front of the upper slit. (a) Describe qualitatively what happens to the interference pattern. (b) Derive an expression for the intensity of the light at points on a...

Homework Statement Given the electric field E = (2x−y2)ax + (3z−2xy)ay + 3yaz, and the piecewise linear path joining the points A(−2,1,−1), P(2,1,−1), Q(2,3,−1) and B(2,3,1), find −∫E⋅dl from A to P − ∫E⋅dl from P to Q − ∫E⋅dl from Q to B along the straight line segments. Homework Equations...

Hi everyone, i hope this is the right place to post this. Anyway, I'm creating a game, and I'm trying to calculate and project future car movement path based on steering angle of the wheels. By using equation: r = wheelbase / sin(steeringAngle) I'm able to calculate turning radius. But the...

Homework Statement Letting c(t) =(t2,t,3) for 0<t<1 (Really it's a smaller than or equal to sign) 1. Find the length of the path 2. Find the average y coordinate along the path Homework Equations What we're given in the book: (These equations are not necessarily relevant) (formula 1) l(c)...

Homework Statement A time-dependent two-dimensional fluid flow is given, in a Cartesian coordinates system (x, y), by the velocity field: u = (y, t-x) Show that, at time t = 0, the streamlines of this flow are circles centred on the origin. Find equation of the streamline that passes through...

Hi all, I'm a college sophomore studying physics and computer science, and I was hoping to get a bit of perspective on graduate school and careers with respect to physics. In high school, I was very much a slacker, who would slide by in the "Honors Classes", but would occasionally do quite well...