Uniform you mean like this if yes then rest is up to you
Yep that's what I actually did. But you may notice that the BOX2D physics bugs. The ball goes through the physic object. It's not normal. I suspect there is no correct behavior for taking in account the rotation for the physics object.
Seems that the physics sometimes miscalculate the collisions while the object is rotating.
But I don't know if I should report this as a bug or not.