You know force equal to function of some, you know mass v v dot r all that, you know u actually v dot   like. It will tell me that. So, what that does not going is not going to tell me the full story. Because I am going to have to find out what is this X, what is this Y? How much does it change does the Y come down with v.
You see, remember this is a same thing what we have done in restoring force, you know see this you you just compare, I just want to tell you this and end it this n in a
with respect to our, you know like roll. This n was nothing, but my m which was nothing, but my rho g v into g m t into or rather G, z we may call rho g v into G z. Remember that this G z graph, if you plot as theta came down G z G z came down. Theta, as theta came down G z could not have gone up because then there would have been a violation.
So, similarly, here I have to find out, if v comes down does Y come down or Y go up. See, it is a necessary condition that, it must come down in order for, it to come to the position. Because as I am bringing back theta to 0 my restoring moment must come to 0 at theta 0, my restoring moment must be 0. Similarly, here when my v becomes 0, my y must be 0. If it was not 0 then it would continue to shift and these are the kind of questions, we will be asking and finding out there is a very...