# How to model perfectly elastic collisions using force?

I want to have elastic collisions in my Newtonian physics simulator, but in the one physics class I've taken we only used momentum when analyzing elastic collisions, and my simulator is totally force-based.

If two pointlike objects are colliding with given velocities and masses, what forces should I have them exert on each other in order to simulate a perfectly elastic collision?

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There's a reason you analyzed such collisions in terms of momentum. The required force is a dirac-delta function of the distance between the particles, which is a strange mathematical object students normally don't encounter until their first quantum mechanics course. –  David H Aug 27 '13 at 4:39
Oh, wow. That's really upsetting. Do you know if there's a good heuristic of some kind? I don't want to break my simulation's "purity" and directly edit velocity. –  Eli Rose Aug 27 '13 at 4:49
Sorry, I'm not the right person to ask for advice on computer simulations. :( –  David H Aug 27 '13 at 5:01
Is this a 1D or 2D/3D simulator? –  Kyle Aug 27 '13 at 18:26
@Kyle It's a 2D simulator –  Eli Rose Aug 27 '13 at 19:24