What type of friction is experienced when a solid moves through a fluid?

When a solid moves through a fluid, it experiences fluid friction, which is also known as viscous or drag friction. This type of friction occurs due to the interaction between the moving solid and the fluid (which can be a liquid or gas). As the solid moves, it displaces the fluid particles surrounding it, and the resistance encountered from those particles creates a force that opposes the motion of the solid.

Fluid friction is crucial in various engineering applications, such as in the design of boats, aircraft, and pipelines, where understanding the drag forces is essential for efficiency and performance. It is distinct from other types of friction like static friction, which occurs when there is no relative motion between surfaces, and rolling friction, which is related to the motion of rolling objects. Air resistance is a specific form of fluid friction that applies when an object is moving through air. However, fluid friction is the broader term that encompasses all interactions between solids and fluids, making it the most accurate choice in this context.