Comprehensive Practice Questions,
Answers & Solutions
(2026-2027)
(Updated | Grade A+)
, Fluid mechanics Study of fluids at rest or in motion
Fluid statics (hydrostatics) Study of fluids at rest
Fluid dynamics Study of fluids in motion
Fluid A substance that deforms continuously when subjected to a shear force of any
magnitude
Can "fluid" and "liquid" be used interchangeably? No, a fluid can be a liquid or gas, but a liquid cannot be a gas
Continuum assumption Mean free path of molecules is much smaller than the dimensions of the container
When does the continuum assumption fail? Nanoscale flows or space/vacuum applications
Density Mass per unit volume
Specific volume Volume per unit mass
Specific gravity Ratio of a fluid density to the density of water at standard conditions
Specific weight Weight per unit volume
Absolute pressure Pressure measured relative to a vacuum
Gage pressure Pressure measured relative to local atmospheric pressure
Pressure relationship Pabs = Patm + Pgage
Cavitation Local pressure drops below vapor pressure causing boiling