Il 12/02/2026 07:30, Luigi Fortunati ha scritto:The Wikipedia entry for "Elastic collision"[ ... ]
https://en.wikipedia.org/wiki/Elastic_collision
contains the following animation
https://youtu.be/wl0c6NMysY4
where the two bodies collide at point x and instantly reverse direction.
I dispute what the moderator wrote.
A body of mass 2m cannot bounce back (in place!) when it collides with a
body of mass m,
And yet, it bounces back, though with a reduced velocity.
otherwise a body of mass 3m, 10m, or 100m would also bounce back.
No, a body of mass 3m would stop cold, and bounce the body of mass m with velocity 2*v.
More massive bodies would continue forward with reduced velocity, and bounce the smaller
body with increased velocity.
It's obvious that a body of mass 100m, colliding with a body of mass m,
can only slow down but not stop in place and bounce back!
Slows down a bit and bounces the smaller body with velocity approaching 3*v.
The formulas are in the text above the animations. (Mind the signs of the vA1,vB1 and vA2,vB2.)
--
pa at panix dot com
| Date | Sujet | # | Auteur | |
| 11 Feb 26 |  Elastic Collision | 15 | Luigi Fortunati | |
| 13 Feb 26 |  Re: Elastic Collision | 5 | Luigi Fortunati | |
| 13 Feb 26 |   Re: Elastic Collision | 1 | Mikko | |
| 13 Feb 26 | Re: Elastic Collision | 1 | Petri Kaukasoina | |
| 13 Feb 26 | Re: Elastic Collision | 1 | Pierre Asselin | |
| 15 Feb 26 |  Re: Elastic Collision | 1 | Luigi Fortunati | |
| 15 Feb 26 | Re: Elastic Collision | 1 | Jonathan Thornburg [remove -color to reply] | |
| 15 Feb 26 | Re: Elastic Collision | 1 | Jonathan Thornburg [remove -color to reply] | |
| 16 Feb 26 | Re: Elastic Collision | 7 | Luigi Fortunati | |
| 28 Feb 26 |  Re: Elastic Collision | 1 | Luigi Fortunati | |
| 28 Feb 26 | Re: Elastic Collision | 1 | Mikko | |
| 5 Mar 26 | Re: Elastic Collision | 1 | Luigi Fortunati | |
| 8 Mar 26 | Re: Elastic Collision | 1 | Mikko | |
| 12 Mar 26 | Re: Elastic Collision | 1 | Luigi Fortunati | |
| 16 Mar 26 | Re: Elastic Collision | 1 | Mikko |
Les messages affichés proviennent d'usenet.