(4) The victim is at least 13 but less than 16 years old and the actor is at least four years older than the victim. Sexual assault is a crime of the second degree. Amended amended 1979, c.178, s.26; 1983, c.249, s.2; 1989, c.228, s.3; 1997, c.194, s.1.
Quick Answer. Pressure is exerted by fluids because of their weight. According to Georgia State University, static fluid pressure is exerted by the depth of the fluid, the density of the fluid and the acceleration of gravity.
Compressible flow (gas dynamics) is the branch of fluid mechanics that deals with flows having significant changes in fluid density. Gases, mostly, display such behaviour. While all flows are compressible, flows are usually treated as being incompressible when the Mach number (the ratio of the speed of the flow to the speed of sound) is less than 0.3 (since the density change due to velocity is about 5% in that case).