vankiz I was replying to Mayfly.
In your capx you are showing reflection angle for the white ball and it's not correct. In the real world billiard game the cue ball can only go backwards if you apply a strong back spin.
You need to show reflection angle of the target (colored) ball. Once you get the angle calculated and shown (as on Mayfly's video), you can adjust physics velocity for the target ball to match that angle.