Using conservation of momentum for ball to ball physics

Question

Is it not a good practice to directly interfere with speed/velocity of an object?

Because I am having problem with my simple ball to ball physics engine. Should I adopt myself to force based thinking? Is it OK to keep working with velocity itself? Is controlling velocity directly, a bad practice? if it is , could it be the reason why my ball to ball physics program is not working?

Answer 1

If you are dealing with balls colliding and bouncing, then conservation of momentum (and energy, if the collisions are elastic) should be all you need. You do still have to determine the direction of contact and constrain the momentum change to be normal to that.

On the other hand, if you want balls to be resting against each other or on surfaces, you need to model the contact forces.