Part 1: Questions

MAAE2400 PA #1 - Jan. 16 - 20th Part 1 Question 4) A pressure gauge at the inlet to a gas compressor indicates that the gauge pressure is 35.0 kPa. Atmospheric pressure is 1.01 bar. The absolute pressure at the exit is 6.0 times the absolute pressure at the inlet. What is the absolute pressure of the gas at the inlet and what is the gauge pressure of the gas at the exit? Question 6) A gas in a piston–cylinder assembly undergoes a process for which the relationship between pressure and volume is pVn = constant. The initial pressure is 1 bar, the initial volume is 0.1 m3, and the final pressure is 9 bar. The value of the polytropic exponent is n = 1.3. Determine the final volume, in m3, and the work for the process, in kJ. Question 7) An object of mass 10 kg, initially at rest, experiences a constant horizontal acceleration of 4 m/s2 due to the action of a resultant force applied for 20 s. Determine the total amount of energy transfer by work, in kJ. Part 2 Question 2 Match Questions 1.1 to 1.10 with the appropriate definition (A-J) 1.1 Boundary 1.2 Closed system 1.3 Control volume 1.4 Extensive property 1.5 Intensive property 1.6 Process 1.7 Property 1.8 State 1.9 Surroundings 1.10 System A. The condition of a system as described by its properties B. A region of space through which mass may flow C. Whatever is studied D. A transformation from one state to another E. A property whose value for an overall system is the sum of its values for the parts into which the system is divided F. Everything external to the system G. A fixed quantity of matter H. A property whose value is independent of the size or extent of a system and may vary from place to place within the system at any moment I. Distinguishes the system from its surroundings J .A macroscopic characteristic of a system to which a numerical value can be assigned at a given time without knowledge of the previous behavior of the system ================================================================================== Fill in the blanks 1.11 A special type of closed system that does not interact in any way with its surroundings is a(n) ________. 1.12 Describe the difference between specific volume expressed on a mass basis and a molar basis ________. 1.13 A system is said to be at ________ if none of its properties changes with time. 1.14 A control volume is a system that: a) b) c) d) always contains the same matter. allows a transfer of matter across its boundary. does not interact in any way with its surroundings. always has a constant volume. 1. 2. 3. 4. What does adiabatic mean? What is the sign convention for heat transfer? For work? What is a thermodynamic cycle? What direction is the net energy transfer by work for a power cycle: in or out? The net energy transfer by heat? 5. What direction is the net energy transfer by work for a refrigeration or heat pump cycle: in or out? The net energy transfer by heat? 6. What is the 1st law of thermodynamics for a closed system? 7. What is internal energy? What are the three modes of energy storage for individual atoms and molecules making up the matter within a system? True or False: 8. A spring is compressed adiabatically. Its internal energy increases. 9. If a system's temperature increases, it must have experienced heat transfer. 10. The total energy of a closed system can change as a result of energy transfer across the system boundary by heat and work and energy transfer accompanying mass flow across the boundary. 11. If a closed system undergoes a process for which the change in total energy is positive, the heat transfer must be positive. 12. If a closed system undergoes a process for which the work is negative and the heat transfer is positive, the total energy of the system must increase. 13. For a system at steady state, no property values change with time. 14. If a closed system undergoes a thermodynamic cycle, there can be no net work or heat transfer.