All that we are saying is that, if there is a disturbance the ship could have actually gone
heave ward, but instead of that it when you remove the disturbance it actually begins to
go again along another straight line. Because going along with straight line implies, v dot
0 and r dot, I mean v and r both there is no v.
Motion in the y direction
Now, motion in the Y direction now motion around Z direction
Z
All thaty.