What term describes mass per unit volume, often expressed as pounds per cubic foot?

What term describes mass per unit volume, often expressed as pounds per cubic foot?

• A. Density
• B. Mass
• C. Volume
• D. Pressure

Answer: (A)

Density is the property that describes how much mass sits in a given volume. It’s calculated as mass divided by volume (rho = m/V). In HVAC work, pounds per cubic foot is a common way to express density, such as for air or refrigerants. If you pack more mass into the same volume, density increases; if you increase the volume with the same mass, density decreases. Mass alone is just the amount of matter, volume is the space it occupies, and pressure is the force per area—none of those describe mass per unit volume.

Density is the property that describes how much mass sits in a given volume. It’s calculated as mass divided by volume (rho = m/V). In HVAC work, pounds per cubic foot is a common way to express density, such as for air or refrigerants. If you pack more mass into the same volume, density increases; if you increase the volume with the same mass, density decreases. Mass alone is just the amount of matter, volume is the space it occupies, and pressure is the force per area—none of those describe mass per unit volume.