The usual Lagrange equations of motion cannot be directly applied to systems with mass varying explicitly with position. In this particular context, a naive application, without any special consideration on non-conservative generalized forces, leads to equations of motions which lack (or exceed) terms of the form 1/2(<FONT FACE=Symbol>¶</font>m/<FONT FACE=Symbol>¶</FONT>q.2), where q is a generalized coordinate. This paper intends to discuss the issue a little further, by treating some applications in offshore engineering under the analytic mechanics point of view.
Lagrange equation; variable mass with position; offshore engineering applications