Hi there, I want to have a cool collision response in my game streets that a lot of bitmap-based cars are going along.I find the collision but its rather difficult to have the cars responde well.consider two car going along the street one at the back of another.If the car behind, hit the other ,how should the two car be going?(I know the ellastic response but Ii think this is a horse of different color,isn''t it?) Thanks alot.

there is the elastic collision... and then there is the INELASTIC collision...
for an inelastic collision, the two cars must stick together, rather than bounce.
the sum of the momentum''s of the two cars equals the momentum of the resulting twisted heap when they crash. i forget the equations to get the momentums of things, but it has to do with their mass and velocity (you can find this equation in any first-year physics book, and probably at plenty of .EDU websites)...
of course, some of the energy is lost due to friction and the sound (yes, even vibrating the air to make a nice BAM sounds wastes energy) so in reality the carwreck will be moving slightly slower than if it happened in space...
also, a car collision in reality is somewhere between elastic and inelastic... they both dent in, which reduces the total energy of the system.

--- krez (krezisback@aol.com)