True or False: For flowing gases the physical properties (including density) are generally

True or False: For flowing gases the physical properties (including density) are generally

• A. True
• B. False
• C. Not determinable
• D. Sometimes

Answer: (B)

In flowing gases, density is not constant. Gases are compressible, so pressure and temperature can change along the flow, and density must adjust accordingly. The relationship rho = P/(R T) (for an ideal gas) shows that as pressure and temperature vary, density changes too. Only in cases where the flow speed is very low (small Mach number) and temperature changes are negligible is density treated as approximately constant, but that’s an approximation, not the general rule. Therefore, the statement is false.

In flowing gases, density is not constant. Gases are compressible, so pressure and temperature can change along the flow, and density must adjust accordingly. The relationship rho = P/(R T) (for an ideal gas) shows that as pressure and temperature vary, density changes too. Only in cases where the flow speed is very low (small Mach number) and temperature changes are negligible is density treated as approximately constant, but that’s an approximation, not the general rule. Therefore, the statement is false.