My Math Forum  

Go Back   My Math Forum > Science Forums > Physics

Physics Physics Forum


Thanks Tree1Thanks
  • 1 Post By Benit13
Reply
 
LinkBack Thread Tools Display Modes
August 20th, 2017, 08:54 PM   #1
Senior Member
 
Joined: May 2015
From: Arlington, VA

Posts: 271
Thanks: 23

Math Focus: Number theory
Cube with spheres bumping within

Take a cubic box of edge E, wherein two spheres of like diameter and mass bounce elastically. Will the box move randomly or not?
Loren is offline  
 
August 20th, 2017, 09:17 PM   #2
Banned Camp
 
Joined: Dec 2012

Posts: 1,028
Thanks: 24

You miss several physical info:

For example if you shake the box to move the balls, or you just launch them etc...

The most simple case is if you have an open box, wide enough, and you just live vertically falling the two (separate) perfectly spherical (of mechanical known characteristic) balls from a fixed eight that is less than the height of the box, and they bump on a perfectly plane (rigid or not) bottom surface... etc... in this case is deterministic, else the problem can becomes non deterministic, for example if you shake the box, than you stop it looking the balls bumping....
complicatemodulus is offline  
August 20th, 2017, 09:32 PM   #3
Senior Member
 
Joined: May 2015
From: Arlington, VA

Posts: 271
Thanks: 23

Math Focus: Number theory
Quote:
For example if you shake the box to move the balls, or you just launch them etc.
Perhaps the result is the same for each regarding randomness/determinism.

I was trying to minimise the parameters of the problem and preserve its basis.
Loren is offline  
August 28th, 2017, 07:19 AM   #4
Senior Member
 
Joined: Apr 2014
From: Glasgow

Posts: 2,068
Thanks: 692

Math Focus: Physics, mathematical modelling, numerical and computational solutions
Quote:
Originally Posted by Loren View Post
Take a cubic box of edge E, wherein two spheres of like diameter and mass bounce elastically. Will the box move randomly or not?
In reality, gases inside boxes exert equal pressure on the six faces of the box and the magnitude of statistical fluctuations for pressure inside the box are so small relative to the force required to overcome friction that no movement occurs. If the box is in a vacuum sitting on a frictionless surface with a gas trapped inside it, statistical variations in pressure can occur, but the acceleration caused by the fluctuations is so tiny that any macroscopic motion is virtually undetectable.

However, statistical dynamics of gases can become very important in some studies. For example, one of the ways of cooling gases down to very low temperatures (e.g. whilst studying Bose-Einstein condensates and the like) is to take a small sample of very-low energy particles and let the ones with the greatest energy out of them all (i.e. those at the top end of the Maxwell-Boltzmann distribution) leave. The net effect on the whole sample is a cooling effect that's somewhat similar to macroscopic evaporative cooling
Thanks from Loren
Benit13 is offline  
Reply

  My Math Forum > Science Forums > Physics

Tags
bumping, cube, spheres



Thread Tools
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
How many red cube can surround a blue cube?(all equal size) rnck Art 1 December 5th, 2015 03:49 AM
Spheres, and more spheres! wuzhe Algebra 1 December 24th, 2012 02:25 PM
spheres Anthony1 Computer Science 6 February 9th, 2011 06:09 AM
math question (cube, cube volume, percent) yano Algebra 8 March 25th, 2010 05:40 PM
math question (cube, cube volume, percent) yano Applied Math 4 December 31st, 1969 04:00 PM





Copyright © 2017 My Math Forum. All rights reserved.