Which are the types of pressure listed?

• A. Gauge, atmospheric, vacuum, and absolute
• B. Hydrostatic, kinetic, static, dynamic
• C. Elastic, plastic, viscous, compressive
• D. Ambient, gauge, hydrostatic, thermal

Answer: (A)

The idea here is to name the standard ways we describe pressure in fluid systems. Atmospheric pressure is the pressure exerted by the surrounding air. Gauge pressure is the pressure measured relative to that atmospheric pressure, which is what a typical pressure gauge reads when it’s open to the atmosphere. Vacuum pressure refers to pressure below atmospheric, often treated as negative gauge pressure. Absolute pressure is the total pressure relative to a perfect vacuum, and it relates to gauge and atmospheric pressure by the equation P_abs = P_gauge + P_atm. These four—gauge, atmospheric, vacuum, and absolute—cover the common ways we categorize pressure in practice.

Other groupings mix concepts that aren’t standalone pressure types: hydrostatic and dynamic describe how pressure is generated in fluids, not distinct classifications of pressure themselves; elastic, plastic, and viscous refer to material or fluid behavior rather than pressure types; ambient is not a standard standalone type of pressure in this context and thermal involves temperature effects rather than a pressure category. So the first set is the complete and correct collection of pressure types.