The normal force per unit area that a fluid exerts on a surface is called Impulse Pressure Gauge pressure Stress

Problem Breakdown

1. Definition of terms: Impulse, Pressure, Gauge pressure, Stress.
2. Identify the concept related to fluid mechanics.

Relevant Concepts

• Pressure is defined as force per unit area applied in a direction perpendicular to the surface of an object.
• The term Stress typically refers to the internal resistance of a material to deformation.

Analysis and Detail

1. Impulse usually refers to the change in momentum and isn't directly related to fluid mechanics in this context.
2. Gauge Pressure refers specifically to the pressure measurement relative to atmospheric pressure, which is important but also not a direct definition of the fluid's force on a surface.
3. Stress, although it involves force per unit area, generally refers to solids rather than fluids.

Verify and Summarize

The correct term that encapsulates the definition of the normal force per unit area that a fluid exerts on a surface is Pressure. It’s the most straightforward definition that aligns with the behavior of fluids in physics.

Final Answer

The normal force per unit area that a fluid exerts on a surface is called Pressure.