The document discusses the fundamental equations of fluid dynamics: A) The continuity equation states that mass is conserved as fluid flows. It relates the rate of change of fluid density to the divergence of fluid velocity. B) The Navier-Stokes equations describe how fluid velocity varies over time and space due to forces such as pressure, viscosity, gravity, etc. They are partial differential equations derived from momentum balance on a fluid parcel. C) Bernoulli's equation relates pressure, density, velocity, elevation, and kinetic energy in fluid flows. It applies to steady, incompressible, inviscid flows and is useful for analyzing potential flows.