Weight per unit volume (density times acceleration due to gravity) is called which term?

Weight per unit volume (density times acceleration due to gravity) is called which term?

• A. Density
• B. Specific Weight
• C. Specific Gravity
• D. Viscosity

Answer: (B)

Specific weight is the weight per unit volume, usually denoted gamma. It comes from the idea that weight is force (due to gravity) acting on a mass, so spreading that force over a volume gives gamma = rho g. This quantity is particularly useful in fluid statics and hydrostatics, for example in the relation p = gamma h, where pressure increases with depth h. Density is just mass per volume (rho), not weight per volume. Specific Gravity is a dimensionless ratio comparing a fluid’s density to a reference density (usually water). Viscosity is a measure of a fluid’s internal resistance to flow, not related to weight per volume.

Specific weight is the weight per unit volume, usually denoted gamma. It comes from the idea that weight is force (due to gravity) acting on a mass, so spreading that force over a volume gives gamma = rho g. This quantity is particularly useful in fluid statics and hydrostatics, for example in the relation p = gamma h, where pressure increases with depth h.

Density is just mass per volume (rho), not weight per volume. Specific Gravity is a dimensionless ratio comparing a fluid’s density to a reference density (usually water). Viscosity is a measure of a fluid’s internal resistance to flow, not related to weight per volume.