So, these kinds of things are all full of mathematics. There are many theories that are developed, which have worked out; what is this correction, speed dependant correction we call to get to the speed dependant added masses. This is all beyond the scope of our this class. It is all part of classical hydrodynamic theories from which these are all developed. Whole lot of Maths, whole lot of you know like abstract Maths are necessary in order to get to this and; obviously, there are different versions because there are no close solutions.