Incorrect velocity transference after new Element/Construction/... creation

[NotSoOld]

It's about managing collision events at high speeds (and destruction because the speed was too high).
It seems to be too late to perform the transference like new.velocity = old.velocity. Old.velocity at this time is already very low as the collision already happened. Should store the velocity value for future application.
The same goes about applying the velocity to detached Fragments. The object which pushed them stopped already, so they receive 0 velocity change after gaining a Rigidbody. Hint: when colliding, the Collision parameter has an impulse property (and, probably, more useful properties), could use it.