Bounce Definition and 124 Threads

  1. U

    Do photons bounce off of each other?

    What would happen if a photon moving in one direction were to meet another photon moving in a perpendicular direction? Would they behave like billiard balls and bounce off each other, would they just pass through each other, would they combine together somehow and move in some new direction, or...
  2. B

    Calculating Bounce Equations for 3D Physics Simulations

    Finding the "bounce equation" Due to reasons forementioned, I am unable to access the necessary data required to avoid the release of the following information: I am making a 3d physics simulation. What are the equations for bounce based on the velocity and elasticity of a sphere when it...
  3. P

    Why some materials bounce off more than the others?

    why some materials bounce off more than the others? What happens with the microstructure?
  4. H

    The art to become special and a bounce

    The art to become special and the bounce. Roger Penrose in his book “The Road to Reality” showed us a road/trajectory from a super special low entropy state, at the Big bang, to nowadays’ less special and higher entropy state. Nothing wrong with symmetric physical laws valid during that...
  5. D

    At what velocity should we bounce the ball

    If we drop a ball from 1.5 m it is bouncing for 3 seconds. At what velocity should we bounce the ball in order to make it reach the height of 1.5 m?
  6. S

    Tennis serve bounce - spin doubles, speed halfs, why?

    First of all, can someone delete my table tennis post? Second, why does a tennis ball in a serve right after it bounces reduces its speed to half and increases its spin to double?
  7. DaveC426913

    Spam bounce back sign of zombiism?

    Occasionally I get administrator emails that indicate emails bounced back. The email is some spam thing. It looks for all the world like I sent that piece of spam, though I have the latest spam blocking s/w. Does this, in fact, mean that my system is affected, or is it a fake?
  8. A

    Why Things Bounce: Exploring the Physics Behind Bouncing Objects

    This is probably a stupid question, but why is it that things bounce back at you when they hit the floor or a wall? When the kinetic energy is transformed into potential energy as the ball compresses, is there a force that transforms the potential energy back into kinetic energy? From my...
  9. H

    Uniqueness of Bojowald's Bounce in the Multiverse

    Is Bojowald’s Bounce unique? (In a sense that the BB’s bounce is the one and only). I foresee 3 possible answers: 1) Yes. But IMO there is no evidence (theoretical or experimental) for this answer. 2) Physics can’t say anything about it. But because of 3) also this answer is wrong. 3) No...
  10. marcus

    Bounce replaces bang: articles in *Nature Physics*

    Bojowald's What happened before the Big Bang? article in the August 2007 issue of NATURE PHYSICS is available to non-subscribers To get the article directly in HTML http://npg.nature.com/nphys/journal/v3/n8/full/nphys654.html Or you can go thru the Table of Contents and see the other...
  11. marcus

    Could a Black Hole Bounce Lead to a New Universe?

    In the past two years work by Ashtekar and others in Loop cosmology has modified the LQG dynamics. Two postdocs at Portsmouth, one of whom is an Ashtekar PhD, have recently studied the Schwarzschild black hole using the improved dynamics. They got some new results which seem to point in the...
  12. wolram

    Can LQC explain the bounce of black holes?

    If theories of cosmology produce a (bounce) what happens to Black holes, it is hard to imagine that these posited things being riped apart.
  13. marcus

    Anisotropic LQC bounce: Bianchi-I case (Chiou and Vandersloot)

    It turns out that this work has a timely significance. In reacting to Martin Bojowald's bounce article in July 2007 Nature Physics one or more blog personalities spoke as if they understood LQC to deal only with the homogeneous and isotropic case. It doesn't. Current LQC does not only deal with...
  14. E

    Tennis ball bouncing on the floor - How high does it bounce?

    Homework Statement A tennis ball bounces on the floor three times. If each time it loses 21% of its energy due to heating, how high does it bounce after the third time, provided we released it 4.6 from the floor? Homework Equations The Attempt at a Solution I just can't deal...
  15. marcus

    Wolfgang Priester forsaw Big Bounce cosmology

    http://arxiv.org/abs/astro-ph/0608644 Wolfgang Priester: from the big bounce to the Lambda-dominated universe James Overduin, Hans-Joachim Blome, Josef Hoell 12 pages, 7 figures, optimized for A4 paper. Partly biographical, partly historical review of subjects to which Priester contributed...
  16. marcus

    Steve Hsu and Loop Gravity's black hole bounce

    Steve Hsu has started a conversation that closely parallels discussion in Loop Quantum Cosmology regarding black hole bounce. http://infoproc.blogspot.com/2006/08/spacetime-topology-change-and-black.html http://arxiv.org/abs/hep-th/0608175 http://arxiv.org/abs/gr-qc/9908031...
  17. marcus

    Black hole bounce comes out of the closet

    This is a long-awaited paper. http://www.arxiv.org/abs/gr-qc/0509075 Quantum geometry and the Schwarzschild singularity Abhay Ashtekar, Martin Bojowald 31 pages, 1 figure IGPG-05-09/01, AEI-2005-132 "In homogeneous cosmologies, quantum geometry effects lead to a resolution of the...
  18. S

    Help 2-dimensional motion, with a bounce

    If a ball is launched from a launcher at a height h and an angle theta and it lands x meters away from its original x position, and bounces, how can I figure out the angle at which it bounces? How does it relate to what I know? And how do I find the new y velocity?
  19. A

    What Makes a Bouncing Ball Bounce?

    this is a rather stupid question: the other day, I found a bouncing ball in my room, and I started boucing it around. And I want to know what makes it bouce?
  20. F

    Angle for maximum height of ball bounce

    There is a ball of mass m. It is at height L (see the picture). The kinetic energy is fixed (=E). What is the angle a, for which the ball catches up the maximum height after one bounce? The bounce is elastic. Thanks, Final.
  21. G

    News What is the difference between Kerry and Bush's campaign policy teams?

    USA TODAY/CNN/Gallup Poll has found that poor Kerry got no convention bounce and he’s pissed ‘cause the fxcking balloons didn’t fall. With the vast number of advisors and consultants all Kerry can manage is to “stand up for the people” whatever that means. No platform, no budget, no...
  22. marcus

    What is the Black Hole Bounce Theory and How Can it Be Tested?

    Smolin has presented a testable theory which offers a possible explanation for some parameters in the Standard Model and in Cosmology. In his recent paper he presents a handful of empirical tests which could shoot down the theory---that is, the theory is falsifiable: it makes predictions...
  23. marcus

    Big Bounce generic, Date and Hossain

    the Big Bounce is generic in LQC, say G.Date and G.Hossain in a new paper http://arxiv.org/gr-qc/0407074 In LQC, as long as there is a scalar matter field, the bounce is generic in the sense of being independent of quantizing ambiguities and details of scalar field dynamics. they also...
  24. A

    Predicting Light Bounce: Mirror vs Wall

    To start, I don't actually mean "how" (the means by which) but rather how to predict where it will bounce. Is it always going to bounce off like it does in a mirror (first angle = end angle relative to line perp to mirror). If so, why is it when you shine a flashlight on a wall, you see the...
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