In fluid mechanics, what term describes a substance in the liquid or gas phase?

In fluid mechanics, what term describes a substance in the liquid or gas phase?

• A. A solid
• B. A fluid
• C. A plasma
• D. A chemical element

Answer: (B)

Fluids are substances that can flow and take the shape of their container, which includes liquids and gases. In fluid mechanics we focus on how these substances move and respond to forces, so the term describes the liquid or gas phase. Solids resist flow and keep their shape, so they aren’t described as fluids. A plasma is a high-energy, ionized gas and, while it can behave like a fluid under some conditions, the common term used for the liquid or gas phase in this context is fluid. A chemical element is a basic substance defined by its atomic structure; its state (solid, liquid, or gas) depends on conditions and isn’t itself a phase descriptor.

Fluids are substances that can flow and take the shape of their container, which includes liquids and gases. In fluid mechanics we focus on how these substances move and respond to forces, so the term describes the liquid or gas phase. Solids resist flow and keep their shape, so they aren’t described as fluids. A plasma is a high-energy, ionized gas and, while it can behave like a fluid under some conditions, the common term used for the liquid or gas phase in this context is fluid. A chemical element is a basic substance defined by its atomic structure; its state (solid, liquid, or gas) depends on conditions and isn’t itself a phase descriptor.