THE UNIVERSITY OF MICHIGAN Department of Mechanical ...
THE UNIVERSITY OF MICHIGAN Department of Mechanical Engineering ME 235 Thermodynamics I / Winter 2014 / Section 002 HW 3 Due date: Jan. 30 2014
2.74 Air in an internal combustion engine has 227oC, 1000 kPa with a volume of 0.1 m3. Now combustion heats it to 1800 K in a constant volume process. What is the mass of air and how high does the pressure become?
2.85 Find the compressibility factor (Z) for saturated vapor ammonia at 100 kPa and at 2000 kPa.
3.11 The sketch shows three physical situations. Show the possible process in a P-v diagram.
3.33 A hydraulic hoist raises a 1750 kg car 1.8 m in an auto repair shop. The hydraulic pump has a constant pressure of 800 kPa on its piston. What is the increase in potential energy of the car and how much volume should the pump displace to deliver that amount of work?
3.46 The R-410A in Problem 3.14 c is at 1000 kPa, 50oC with mass 0.1 kg. It is cooled so the volume is reduced to half the initial volume. The piston mass and gravitation is such that a pressure of 400 kPa will float the piston. Find the work in the process.
Fig. P3.14 (c) 3.47 A 400-L tank A, see figure P3.47, contains argon gas at 250 kPa, 30 oC. Cylinder B, having a frictionless piston of such mass that a pressure of 150 kPa will float it, is initially empty. The valve is opened and argon flows into B and eventually reaches a uniform state of 150 kPa, 30 oC throughout. What is the work done by the argon?
Fig. P3.48. 3.48 A piston cylinder contains 2 kg of liquid water at 20oC and 300 kPa, as shown in Fig. P3.48. There is a linear spring mounted on the piston such that when the water is heated the pressure reaches 3 MPa with a volume of 0.1 m3. a) Find the final temperature. b) Plot the process in a P-v diagram. c) Find the work in the process. Fig. P3.48.
3.50 Heat transfer to a block of 1.5 kg ice at -10oC melts it to liquid at 10oC in a kitchen. How much work does the water gives out?
2.74 Air in an internal combustion engine has 227oC, 1000 kPa with a volume of 0.1 m3. Now combustion heats it to 1800 K in a constant volume process. What is the mass of air and how high does the pressure become?
2.85 Find the compressibility factor (Z) for saturated vapor ammonia at 100 kPa and at 2000 kPa.
3.11 The sketch shows three physical situations. Show the possible process in a P-v diagram.
3.33 A hydraulic hoist raises a 1750 kg car 1.8 m in an auto repair shop. The hydraulic pump has a constant pressure of 800 kPa on its piston. What is the increase in potential energy of the car and how much volume should the pump displace to deliver that amount of work?
3.46 The R-410A in Problem 3.14 c is at 1000 kPa, 50oC with mass 0.1 kg. It is cooled so the volume is reduced to half the initial volume. The piston mass and gravitation is such that a pressure of 400 kPa will float the piston. Find the work in the process.
Fig. P3.14 (c) 3.47 A 400-L tank A, see figure P3.47, contains argon gas at 250 kPa, 30 oC. Cylinder B, having a frictionless piston of such mass that a pressure of 150 kPa will float it, is initially empty. The valve is opened and argon flows into B and eventually reaches a uniform state of 150 kPa, 30 oC throughout. What is the work done by the argon?
Fig. P3.48. 3.48 A piston cylinder contains 2 kg of liquid water at 20oC and 300 kPa, as shown in Fig. P3.48. There is a linear spring mounted on the piston such that when the water is heated the pressure reaches 3 MPa with a volume of 0.1 m3. a) Find the final temperature. b) Plot the process in a P-v diagram. c) Find the work in the process. Fig. P3.48.
3.50 Heat transfer to a block of 1.5 kg ice at -10oC melts it to liquid at 10oC in a kitchen. How much work does the water gives out?
