Collisions Definition and 709 Threads

  1. R

    The problem of excitation of vibrations during collisions

    Homework Statement Dear colleagues, my problem is following: The ball of mass with the initial velocity collides with a system of two identical balls of mass each, connected by a massless hookean spring with stiffness and length . It is necessary to find the final velocities of the...
  2. Stitch1775

    Momentum and collisions homework help

    I need help, I've been staring at this problem for over an hour and trying to find similar problems online with no luck. A 65 kg person is skiing down a hill. The skier's speed at the bottom is 15 m/s. If the skier hits a snowdrift and stops in .30s A)how far does the skier go into the drift...
  3. M

    B Moving Center of Mass Collisions

    If I fire an electron and positron bunch both in the same direction away from my experimental accelerator rest frame such that the electron bunch is fired with higher energy towards a "read end" collision with an already fired positron bunch and they collide a short distance away from the...
  4. P

    Final velocities of two objects in a 2D elastic collision

    Homework Statement An atomic nucleous of mass m traveling with speed v collides elastically with a target particle of mass 3.0m (initially at rest) and is scattered at 45o (a). What are the final speeds of the two particles? Advice: eliminate the target particle's recoil angle by manipulating...
  5. neilparker62

    Collisions Toolkit: Impulse, Momentum & Energy Formulas

    Just thought I'd post a couple of formulas which I have found useful when assisting (or should I say attempting to assist!) with collisions problems in the "Homework" forums. These formulas work on the basic premise that a collision is essentially a "Newton 3 event" in which equal and opposite...
  6. YMMMA

    What is the direction of the velocity/ elastic collisions.

    Homework Statement in the attached file Homework Equations Momemtum = mass - velocity The Attempt at a Solution I solved it E. Since object 2 has the larger mass, the effect is less and will move backwards a little bit.
  7. N

    Newton's Second Law: Understanding Forces, Masses, and Acceleration

    Homework Statement Two identical trucks traveling at different constant speeds are about to collide. The trucks are traveling in opposite directions with truck A going at a velocity of 3m/s right and truck B going at 4m/s left. During the collision, will the magnitude of the acceleration of...
  8. Sandeep T S

    Why is momentum conserved in elastic and inelastic collisions?

    Why momentum conserved in elastic collision and inelastic collision? Please attach mathematical proof too
  9. T

    B Neutron Star Collisions: Creation of Heavy Elements and Their Fate

    When neutron stars collide, heavy elements, such as gold, are created. Are these elements ejected from the system to be found, say, here on earth? Or do they fall back into the newly created black hole?
  10. A

    Analyzing Elastic Collisions w/ Conservation of Energy and Momentum

    Homework Statement There is a 4 kg mass that has a speed of 6 m/sec on a horizontal frictionless surface. The mass collides head-on and elastically with an identical 4 kg mass initially at rest. The final speed of the first 4 kg mass is: (a) 0 m/s (b) 2 m/s (c) 3 m/s (d) 6 m/s Homework...
  11. J

    Energy Lost During Purely Inelastic Collisions

    I'm curious about how the math comes out when you apply conservation of momentum to the theoretical problem of a moving object having a purely inelastic collision with another stationary object in a single dimension. Since the velocity of the combined object is entirely determined by the...
  12. gibberingmouther

    Why Are Relative Velocities in Elastic Collisions Frame-Independent?

    Homework Statement "For a two-particle interaction, the relative velocity between the two vectors is independent of the choice of relatively inertial reference frames." and "The change in kinetic energy is independent of the choice of relatively inertial reference frames." My textbook says...
  13. Soffie

    B Distinguishing between interactions (decays and collisions)

    I always struggle to know which force (strong nuclear, electromagnetic, weak, gravity) is responsible for an interaction. For example, pi+ + pi- = neutron + pi0 I would say its strong force responsible, because quarks are involved. But the pions are also charged, so how do I know it's not...
  14. mfb

    I SuperKEKB/Belle II start up: First collisions

    This year we have two big particle physics accelerators running. SuperKEKB is an upgrade of KEKB, and the Belle II experiment at the accelerator is an upgrade of - you guessed it - Belle. It is located at KEK*, close to Tokyo in Japan, and it is starting up for the first time now. SuperKEKB is...
  15. mfb

    I LHC finishes proton-proton collisions in 2018

    New year, new thread! Here was 2017. Yesterday the first beams this year circulated in the LHC. As every year, the machine operators start with a single low intensity bunch, checking that everything still works properly, and adjusting some parameters where the conditions changed over the winter...
  16. phantom lancer

    Physics Word Problem: Arrow and moving target collision

    Homework Statement Find the 2 unknown variables.[/B]Homework Equations Am I doing this right? Can someone help me find the solution?[/B] The Attempt at a Solution To compute for the velocity of the target/arrow combination immediately after the collision: M_bV_{bi}=M_bV_{bf}+M_wV_{wf}...
  17. phyzguy

    A Neutron star collisions as a heavy element source

    There was a lot of discussion after the recent observation of the merger of two neutron stars about whether or not these events are the source of the heavier elements. See this thread, for example. This recent paper has some new analysis. Especially interesting is Figure 10, that I've...
  18. G

    I Bremmstrahlung in neutral atom collisions

    I found an old paper online (1962) I think, stating that bremmstahlung occurs between different neutral atoms in collisions. Am I correct in assuming that this will result in frequencies outside of the usual line broadening mechanisms? Thanks
  19. G

    I Do neutral atom collisions affect the continuous nature of black body radiation?

    I’ve read everything I can here and in the stack exchange on the topic of the continuous nature of black body radiation and it’s been really helpful,but I’m lead now to this question. Do neutral atom collisions shift the eigenfunctions,during the collisions? Do collisions create temporary...
  20. R

    Elastic and inelstic collisions conceptual questions.

    Homework Statement The questions showed in the pictures ask me whether the collisions in the drawings could be elastic or inelastic, I am not given any mass, the angles are a little vague but I think B and C are supposed to be π/2 and π respectively. For velocity, I am just given the direction...
  21. J

    Sequental elastic and inelastic collisions

    Homework Statement A taxi car weighing 2000kg hits a stationary mini-van that has a mass of 2200kg. The taxi stops and the mini-van rolls and hits a stationary sports car with a mass of 1830kg. Their bumbers hit and they move together at 2.3m/s. What is the velocity of the taxi before the...
  22. U

    Question about Momentum and Collisions

    Homework Statement a)Two balls of equal masses undergo and elastic collision on a pool table. The final velocities of the two balls are v1=18m/s [S10W] and v2= 14m/s [S30E]. If the initial velocity of the first ball was w1=16m/s [S15E], what was the initial velocity of the second ball? b)...
  23. B

    Any plans to expose exact force and torque added during collisions

    This has been a huge limitation for me since picking up unity. So there's "Collision.relativeVelocity" which doesn't even represent a before/after change. There's "Collision.impulse" which gives some kind of averaged force. But collisions add force at points resulting in both force and torque...
  24. T

    Feynman's explanation of atomic collisions in gas

    In the first volume of his lectures' books, Feynman tries to mathematically describe that in a particular gas ( particular because in this case is the sum of 2 monoatomic gasses with different masses) as a result of the collisions beetween atoms it will be equally likely to find any pair moving...
  25. C

    Collision in moving water-angle of rebound

    Hi all! I was having a conversation with a (rather young) friend about the following imaginary situation- suppose you are in a helicopter, at rest relative to the ground. So you are basically seeing a 'top' view. Say you have a a wall fixed to the ground, and it is kept in the middle of a moving...
  26. R

    I Detecting Asteroid Collisions: 'Oumuamua & Radio Telescopes

    A reasonably read and educated laymen, would response to a claim that science and technology still have no means to detect a big asteroid collision with earth, by saying that according to what he read and saw in communication channels reliable enough, an object of that size on course to hit...
  27. C

    Unlocking Realistic Rotational Collisions with Physics & Graphics Engines

    Hi all! I'm currently working on a graphics/physics engine. The following Wikipedia page was extremely helpful in making rectilinear collisions look natural: https://en.wikipedia.org/wiki/Elastic_collision#Two-dimensional Specifically, the very general vector form of the equation on the bottom...
  28. H

    I Are new nucleons formed in heavy-ion collisions?

    The subject heading says it all. In heavy-ion high energy collisions that form a quark gluon plasma (QGP), is it known whether new nucleons are formed from the added energy, or are all of the QGP's quarks ones that existed previously in the colliding heavy ion nuclei? More specifically, are...
  29. R

    Elastic collisions and Newton's third law

    Hi everyone, I am new to this forum, and I'm having a hard time understanding Newton's third law and collisions, first of all I want to say that it is not homework and that I do know the basics of physics, vectors, energy, work, and momentum I also know and understand Newton's first and second...
  30. C

    Momentum, Energy, and Elastic Collisions

    Hello guys. So this is less about about the physics problem and more about the concepts behind it. I don't need help with any solution but I am framing my questions around the example given. So there are two steel balls with equal mass that are hanging from a point by a string. Both strings are...
  31. M

    I Heavy elements from neutron star collisions?

    I have seen it claimed online that the recently announced observation of a neutron-star merger by LIGO provides strong support for the hypothesis that heavy elements - gold and platinum were mentioned in particular - are mostly created in neutron-star collisions rather than in supernovas. Is...
  32. Lukanol

    Conservation of momentum on relativistic collisions

    1. Homework Statement ( This question is from the textbook of Introduction to Elementary Particle Physics, written by Griffiths, on the problem set of Chapter 3 ) Particle A (energy E) hits particle B (at rest), producing particles C1, C2, ...: A + B → C1 + C2 + ... + CN. Calculate the...
  33. T

    I Does LHC like collisions occur naturally

    Does collisions like those in the LHC happen naturally, producing exotic particles, like the Higgs boson?
  34. C

    Gun-projectile Elastic Collisions

    So I'm reading my textbook and there's a problem asking what the muzzle speed of a projectile would be if the gun it is being fired from is free to recoil. I'm given the muzzle speed of the projectile when the gun is stationary, the mass of the projectile, and the mass of the gun. I'm also told...
  35. J

    B Why does Fdt go away during collisions while Fdx does not?

    For collisions between particles, Fdt goes to zero while Fdx does not F = mdv/dt mv + Fdt = mv if you have two particles colliding mva + mvb +Fdt = mva'+mvb' in the above case, Fdt goes away as there are equal and opposite forces between the two particles during the collision, linear momentum is...
  36. unseeingdog

    B Coefficient of Restitution in x and y

    I am currently studying collisions in high school and my teacher told us that, in order to calculate the direction of each object after a 2-body collision, we could change the values in the relative velocity terms of the equation of the coefficient of restitution to the components in x and y. Is...
  37. jophys

    Center of mass oblique collisions

    Hi, in terms of oblique collisions, COM frames and laboratory frames, is this statements ALWAYS true? "The scattering angle of the first particle in the laboratory frame is half of the scattering angle in the center of mass frame." Please elaborate if you know, thanks in advance!
  38. gelfand

    Conservation of momentum, collisions - what about friction?

    I would like to check my understanding for this problem : A puck with mass ##3m## is stationary on a horizontal friction-less surface. It is being impacted in an elastic head-on collision by another puck with the mass ##2m## traveling with speed ##u## to the right. Find the speed and direction...
  39. caters

    Are asteroid collisions as dangerous as they seem?

    The generation ship in my fictional story was built by aliens that know how to use these 3 things: Artificial gravity to make it feel like Earth throughout the ship. Controlled nuclear fusion with 6 tanks. Only 1 needs to be fueled and you have fuel that will last for at least thousands if not...
  40. V

    Can total KE ever increase for inelastic collisions?

    Homework Statement Is following statement True or False? For inelastic collusions, the total KE of colliding objects just after collision is less than the total KE just before collision. The answer is given as False with a mention saying: "This is normally true but in some cases it could...
  41. H

    Collisions -- conceptual questions

    Homework Statement Let two particles of equal mass m collide. Particle 1 has initial velocity v, directed to the right, and particle 2 is initially stationary. A: If the collision is elastic, what are the final velocities v_1 and v_2 of particles 1 and 2? B: Now assume that the mass of...
  42. T

    Approximating number of collisions in canal ray tube

    Homework Statement Canal rays, i.e., positive ion rays are generated in a gas discharge tube. How often does an ion (r= 0.05 nm) collide with an atom of the ideal filler gas(r= 0.1 nm) if it travels 1 m in a straight path through the discharge tube and if the pressure in the tube is 1 mbar? 1...
  43. minnyveller

    Why does the equation for elastic collisions work like this?

    Hi guys. Feels dumb coming back to this but I seem to have confused myself I was helping a friend with the problem: You shoot protons going v=4.2e7 m/s through a particle accelerator. They collide with gas particles of an unknown mass (pretend no velocity) and all bounce back elastically at...
  44. xjcov

    Analysis of collisions from data

    Good afternoon! I would like to preface by saying, yes, this is for a project. I am only posting here to see if my method of solving is correct before I finish the project incorrectly. Homework Statement I chose two balls, mass A: .553 kg and mass B: .410 kg I recorded their collision and...
  45. S

    I What is the significance of calculating the average value of cos?

    In kinetic theory, the number of molecules hitting a unit area of a surface per unit time with speeds between v and v + dv and angles between \theta and \theta + d \theta is found to be a function of sin(theta) and cos(theta). There will often be a practice problem asking to show that the...
  46. U

    Linear momentum in oblique collisions and generally

    In an oblique collision my understanding is that linear momentum is conserved in all directions (x, y, normal, tangential). But in a constrained oblique collision, does this change? For example if we had a block lying between two frictionless surfaces with an angled face ( a slope on one face)...
  47. P

    What Happens to Kinetic Energy in Inelastic Collisions in Space?

    Let's say that 2 objects inelastically collided in outer space. One has a Mass of 2kg, and velocity 5m/s. The other has a Mass of 4kg, and velocity is 0m/s. ( at rest) 1) Energy cannot be created or destroyed. (Energy is conserved) 2) Momentum is conserved. Total Momentum before was (2x5) +...
  48. L

    Liquids: Pascal's Principle and fluid collisions

    Take a U-shaped piece of pipe, standing upwards. Fill the bottom part with liquid and leave the 'prongs' open. Now slam a parcel of liquid into one end at high speed. The other end will experience some momentum exchange and go pushed upwards. Now take the same test case and add some piping...
  49. gabi123

    I Can Antiparticles Collide with Each Other and Create Energy?

    Now it is common knowledge that antiparticles destroy particles on collision, and release the same amount of energy as if the masses of the two particles were combined and plugged into E=mc^2. But what about an antiparticle colliding with another antiparticle? Would they have the same effect on...
  50. J

    MCAT Collisions of a wooden block and bullet

    Hi guys, I'm currently going over Berkerley Review Physics example problem and got confused on a question: Ex. 4.1a : A sharpshooter fires a gun at a wooden block of mass M. If the bullet, of mass (m), becomes lodged inside the block, then which of the following is NOT true? The answer was...
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