See now we are going to talk about something very important of course, all parts are important, but important from the application point of view. What happen? What I am I term this as well you can say dynamic effects. Let me call this as dynamic effects. See when the ship is going in a rough sea that is what this sea keeping about no he ship is traveling here. You are interested in certain behavioral aspect of the ship, you want to find out how comfortable it is etcetera. You are not really looking at motion parts say by itself what for example, what you are looking at things like, whether