Final answer:
A normal shock flow involves a sudden change in flow velocity, temperature, pressure, and density. Flow rate differs from fluid velocity and is dependent on the cross-sectional area. Fluids are categorized as incompressible or compressible based on their density changes with pressure.
Step-by-step explanation:
A normal shock flow is characterized by a sudden and simultaneous change in multiple flow properties. This includes: 1) a sudden change in flow velocity, 2) a sudden change in flow temperature, 3) a sudden change in flow pressure, and 4) a sudden change in flow density. All these changes occur almost instantaneously as the flow crosses the shock wave.
In other contexts, these changes can be described as a change in momentum (related to changes in velocity and pressure) and a rate of change of momentum (related to how quickly these changes occur). The flow rate, which is the volume of fluid flowing per unit time, is different from fluid velocity, which is the speed at which the fluid elements are moving. The flow rate is related to the fluid velocity and the cross-sectional area through which the fluid is flowing.
One way to visualize fluid motion is through the use of velocity vectors, as shown in meteorology maps describing wind patterns. Furthermore, fluids can be characterized as incompressible or compressible. Incompressible substances do not change density significantly with pressure (like water), while compressible substances do (like air at high velocities).