11. The mass rate balance is defined as the sum of all inlet mass flow rates minus the sum of all outlet mass flow rates. A: True B: False 12. For one-dimensional flow, mass flow rate is the product of density, area, and velocity. A: True B: False 13. As velocity decreases in a diffuser, pressure decreases. A: True B: False 14. Flow work is the work done on a flowing stream by a paddle wheel or piston. A: True B: False II. Checking understanding 1. The time rate of mass flow per unit area is called Answer: 2. means all properties are unchanging in time. 3. A system consists of liquid water in equilibrium with a gaseous mixture of air and water vapor. How many phases are present? Does the system consist of a pure substance? Explain. Answer: 4. Does the red line in the picture below follow a constant pressure?

Fig: 1