In this task you will be given a text passage from a trivia quiz. You should choose the category this question belongs to from these categories: History, Science, Social Science, Fine Arts, Literature. You can only choose one category, so if in doubt, please choose the closest match.
Q: The Boussinesq approximation of this relation reduces nonlinearity in the body in question by ignoring non-gravitational contributions of density. In another form, the insertion 2 omega cross u-sub-r accounts for motion in a rotating reference frame, and it also has two nonspecific variations that cover compressible and incompressible fluids. One of its most important solutions defines the conditions for Hagen-Poiseuille Flow. This equation relates viscosity, the pressure gradient and density to the partial derivative of velocity with respect to time. FTP, name this equation that describes the momentum of fluids at low speeds.
A:
Science