What does 'fluid dynamics' study?

Fluid dynamics is a branch of physics and engineering that focuses on the behavior of fluids (liquids and gases) in motion. The study encompasses how fluids interact with various forces, such as pressure, gravity, and viscosity, and how these forces affect the movement and flow patterns of the fluid. This area also investigates phenomena such as turbulence, laminar flow, and flow rates, which are critical for applications ranging from aerodynamics to hydraulic engineering.

In contrast to the other options, the study of solid objects and their motion is classified under mechanics, not fluid dynamics. The transfer of thermal energy relates to thermodynamics and heat transfer, which, while they can involve fluids, are distinct fields focusing more on energy exchange rather than flow behavior. Finally, the chemical properties of fluids fall under physical chemistry and fluid chemistry, which are concerned with the substances that make up the fluids and their interactions at a molecular level rather than their movement and behavior. Therefore, the focus of fluid dynamics is specifically on the motion and behavior of fluids, making the chosen answer the most accurate representation of the field.