Read about classical | 24 Discussions | Page 1

  1. nineteen

    B Does speed of light depend on the wavelength or frequency of it?

    I heard that the speed of light doesn't depend on the wavelength or frequency of it, how does it happen? I don't understand it because the ultimate equation is c = fλ (where c is the speed of velocity of light, f is the frequency and λ is the wavelength of it....).
  2. T

    Reference frames and Galilean transformation

    Homework Statement I am having a issue relating part of this question to the Galilean transformation. Question Relative to the laboratory, a rod of rest length ##l_0## moves in its own line with velocity u. A particle moves in the same line with equal and opposite velocity . How long dose it...
  3. qttv

    A Classical Mechanics: Continuous or Discrete universe

    Good morning. The question of the "continuous" or "discrete" nature of the universe is the subject of diatribe among the greatest physicists in the world. I would like to discuss the same topic, but asking a question about the aspect of continuum in classical mechanics. The use of mathematical...
  4. W

    I Motion of a particle from its momentum distribution

    Hi all, I recently learnt the concept of Maxwell's speed distribution and became interested in how to use similar momentum distributions to study the probabilistic motion of a classical free particle. I have done some of my own reading on probabilities and distributions (no formal lessons yet)...
  5. W

    Generalized Velocity: Lagrangian

    Homework Statement [/B] In this example, I know that I can define the horizontal contribution of kinetic energy to the ball as ##\frac{1}{2}m(\dot{x} + \dot{X})^2##. In the following example, Mass ##M_{x1}##'s horizontal contribution to KE is defined as ##\frac{1}{2}m(\dot{X} -...
  6. W

    Lagrangian: Pendulum down a slope

    Homework Statement I have the answer for part a, which is: $$\theta '' + \frac{a}{r} \cos \theta + \frac{g}{r} \sin \theta$$ My issue lies with getting the following equation of motion for part b, $$\theta '' + \frac{g}{r} \cos \alpha \sin \theta = 0$$ Homework Equations The Attempt at...
  7. mcaay

    Lagrange Multipliers in Classical Mechanics - exercise 1

    Homework Statement The skier is skiing without friction down the mountain, being all the time in a specified plane. The skier's altitude y(x) is described as a certain defined function of parameter x, which stands for the horizontal distance of the skier from the initial position. The skier is...
  8. maltmana

    I Planetary Orbits: Force needed for circular orbit

    Hi! first time poster here. I'm making an orbital simulation and I am having a problem with one minor detail. The gravity is working great, and I've programmed it using this formula: A force vector is applied = DirectionOfCentralBodyNormalized * ((GravConstant * centralbodymass *...
  9. C

    I Goldstein Action-angle Variables

    I'm currently working (slowly) through Goldstein (et al), 3rd Edition, and a remark in the section on Action-angle Varibles for Completely Separable Systems (10.7) is giving me pause. We're told that the orbit equations for all ##(q_i, p_i)## pairs in phase space describe libration or periodic...
  10. A

    How to find maximum force on a velocity vs time graph

    The velocity versus time graph is the following: http://imgur.com/kyebx8H As the title asks, how would you find the maximum force on a velocity vs time graph given nothing but the graph and the mass of the object in question. My reasoning was that since f = ma and m is never changing, that...
  11. F

    Classical Need a Classical Mechanics book that covers these topics

    I'm a freshman in Computer Engineering at a university. I have a Classical Mechanics course that will cover these topics: Newton's law of motion Vector Algebra Equilibrium of bodies Plane Trusses First moment of area, centroid, etc. Calculation of virtual displacement and virtual work...
  12. D

    Classical The best physics books to build theoretical knowledge

    Could you name your best picks of books that expand on the high school knowledge. Example is the Goldsteins Classical Mechanics which is a classic. What do you recommend for Electricity and Magnetism, Optics, Relativity and Quantum Mechanics? Also what would be the same criteria for some Math...
  13. brad2292

    I How do we formulate the electromagnetic Lagrangian?

    I'm trying to understand how we set up the lagrangian for a charged particle in an electromagnetic field. I know that the lagrangian is given by $$L = \frac{m}{2}\mathbf{\dot{r}}\cdot \mathbf{\dot{r}} -q\phi +q\mathbf{\dot{r}}\cdot \mathbf{A} $$ I can use this to derive the Lorentz force law...
  14. O

    A satellite, the sun and the satellites heat protector

    Homework Statement A spacecraft is protected from the Sun’s radiation by a planar baffle whose size is much greater than that of the spacecraft itself. The baffle is aligned perpendicular to the direction of the Sun. Show that the equilibrium temperature of the baffle is...
  15. DeldotB

    Calculate the Lagrangian of a coupled pendulum system

    Homework Statement Calculate the Lagrangian of this set up: Imagine having two ropes: They are both attached to the ceiling and have different lengths. One has length b and the other has length 4b. Say they are hooked to the ceiling a distance 4b apart. Now, the ropes are both hooked to a...
  16. bananabandana

    Euler Lagrange Derivation (Taylor Series)

    Mod note: Moved from Homework section 1. Homework Statement Understand most of the derivation of the E-L just fine, but am confused about the fact that we can somehow Taylor expand ##L## in this way: $$ L\bigg[ y+\alpha\eta(x),y'+\alpha \eta^{'}(x),x\bigg] = L \bigg[ y, y',x\bigg] +...
  17. G

    Quantum Mechanics, Cart filling, + friction as it moves

    Homework Statement A cart roles down the track with an initial velocity vo. Because of falling rain, water starts filling the cart such that its mass increases linearly with time. The rain that has fallen on the track cause the wagon to experience a frictional force characterized with a...
  18. R

    What causes the liquid to rise in this picture?

    This is a diagram of a pitot-static tube. My question is however not related to its applications but rather, what causes the liquid to rise up the static tube? The static tube is at right angles to the fluid flow. I understand that this is a very basic question but I can't seem to get my head...
  19. B

    The real freefall

    We always consider the accelaration as a constant thing, while calculating the freefall problems. What if we try to calculate the real. I mean taking the accelaration GM/x^2. I tried it but i could not handle that integral(Just graduated from high school). I would be happy if you reply. Thank you
  20. G

    Prefactor of classical electron radius

    Hi, Assuming the electron is a sphere of finite extent, the classical electron radius is derived by equating the energy of the electric field with mec2. For the computation of the field energy, we have to assume a charge distribution. Both constant charge density and constant surface density...
  21. C

    Stress tensor from action in Landau-Ginzburg field theory

    I would appreciate any help with the following question: I know that for relativistic field theories, the stress tensor can be obtained from the classical action by differentiating with respect to the metric, as is explained on the wikipedia page...
  22. J

    What are momentum,configuration and coordinate spaces?

    What is a momentum space,a coordinate space and a configuration space? Are they in classical or quantum mechanics or both? What are their similarities and differences and when,where and how are they used? thank you in advance!
  23. C

    Physics Puzzle Problem

    So I've been trying to do some physics puzzles and I've come across this in a book called "200 puzzling physics problems." The solution in the back makes no sense to me and I can't seem to figure it out by myself. Can anyone help me?
  24. Diego Fernandez

    Very simple question (basic kinematics)

    Homework Statement I'm taking my first basic physics course and I came across this simple question (which I got the wrong answer apparently). The question was this: what is the velocity and acceleration of an object which has reached it's maximum height after being thrown directly upwards...
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