Talk:Coefficient of restitution
The article states that a cannonball has a low Coefficient of Restitution. I'm not so sure about that. Certainly a ball bearing has a very high Coefficient of Restitution as demonstrated when one bounces a ball bearing on a piece of concrete. If one dropped a cannonball on a suitably non-deforming surface, might it bounce quite high? --Dumbo1 16:28, 13 January 2006 (UTC)
- I suppose it depends on the surface. That confuses things a lot and I can't be positive that the article is right. Run! 18:04, 13 January 2006 (UTC)
- If the surface deforms, then the height of the bounce will depend to some degree on the coefficient of restitution of the surface, as well as that of the object bouncing. I think the article is wrong in this respect, specifically that of the example of the cannonball. At a guess I think that the coefficient of a cannonball is greater not less than that of a rubberball. --Dumbo1 00:59, 2 February 2006 (UTC)
- the coefficient of restituion all depends on the to materials interacting. For example, a ball bearing bouncing on solid steel has a high coefficient of resitution, but that same ball bearing boucing on, say, vinyl flooring will have a much lower coefficient of restituion. (Cabin Tom 03:29, 20 April 2006 (UTC))
I've basically entirely rewritten the page, expanding it from a stub. I couldn't find a reference to the equations I listed in "Usage" for the general collision case. They are modified slightly from equations listed in Tricks of the Game Programming Gurus 2nd Edition by Andre Lamothe and the equations listed on the elastic collision page. --Numsgil 02:23, 11 February 2006 (UTC)
I've added an equation for the coefficient that uses height¹. --Lewk_of_Serthic contrib talk 02:05, 24 February 2006 (UTC)
Someone needs to fix something here, specifically having to do with the "Failed to parse (Can't write to or create math output directory)" messages that are showing instead of the equations. I'd do it if I knew how... (Cabin Tom 03:31, 20 April 2006 (UTC))
- What "failed to parse" messages? --Numsgil 06:22, 20 April 2006 (UTC)
- It seems to have been fixed...(Cabin Tom 23:43, 22 April 2006 (UTC))
Equation Sign
Seems to be disagreement both on the page and on the web about what the signs of the equations need to be.
As I understand it COR is, for any realistic collision, positive and between 0 and 1. Maybe an sbsolute value would take care of this? --Numsgil 02:18, 21 April 2006 (UTC)
Landmine Example
I wonder if that is a good example. After all the collision is not generating kietic energy, rather the chemical potential of the explosive is being converted to heat, which in turn give the objects kinetic energy. Any opinions? 147.10.17.211 13:20, 31 May 2006 (UTC)