when multiple collisions occur between balls..sometimes they stick together..mostly in cases of either of the balls having high velocity..can somebody explain pls
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There's probably something on the balls causing them to stick together. Try cleaning them with a soft cloth or wet paper towel.
Can we see some physics code? How are you handling it? What do you mean by 'multiple collisions'? We're going to struggle helping without more detail.
Only reason I can think of is that the physics is treating it as a collision rather than an explosion (i.e. they stick together instead of flying apart).
EDIT: You could've said that in the original post. I also found this post on gamedev.net:
The problem is probably that your movement speeds mean the balls end up inside each other, and you do collision from there. A better option would be seeing if the objects intersect, and separating them before trying to move them.