ME 211
HW #8
20 December 2011
1. A piston/cylinder contains 2-kg water at 150C, 400 kPa. The piston is slowly moved to expand
the water in an isothermal process to a pressure of 200 kPa. Heat transfer
ME 211
HW #3
1. A piston/cylinder arrangement shown below contains nitrogen at 150 kPa, 30C. The 50-kg piston
has a diameter of 0.1 m and initially sitting on the stops. The atmosphere is at 100 kPa a
ME 211
21 September 2011
HW #1
2
1. The acceleration of gravity is 9.80665 m/s . What is the force needed to hold a mass of 3.000 kg
at rest in this gravitational field? How much mass can a force of 2
ME 211
Solution to HW #2
1. A piston-cylinder device initially contains 1.4-kg saturated liquid water at 200C. Now heat is
transferred to the water until the volume quadruples and the cylinder contain
ME 211
8 December 2011
HW #7
1. A 600-MW steam power plant, which is cooled by a nearby river, has a thermal efficiency of 40
percent. Determine the rate of heat transfer to the river water. Will the
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HW #3
06 October 2011
1. A piston/cylinder arrangement shown below contains nitrogen at 150 kPa, 30C. The 50-kg piston
has a diameter of 0.1 m and initially sitting on the stops. The atmosphere
ME 211
8 December 2011
HW #7
1. A 600-MW steam power plant, which is cooled by a nearby river, has a thermal efficiency of 40
percent. Determine the rate of heat transfer to the river water. Will the
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Solution to HW #4
1. Two kilograms of water is maintained in a weighted piston-cylinder assembly at 3 MPa and
250C. Water is slowly heated at constant pressure until the temperature reaches 350
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HW #5
4 November 2011
1. Refrigerant 134a at 50C, 1.0 MPa is throttled to 0.2 MPa. Assume no changes in the kinetic
energy.
(1) Find the exit temperature assuming ideal-gas behavior.
(2) Calcul
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HW #6
24 November 2011
1. A rigid tank with the volume of 1 m3 contains air at 500 kPa, 20C. The tank is connected to a line
flowing air at 2 MPa, 20C. The valve is opened, allowing air to flow
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26 October 2011
HW #4
1. Two kilograms of water is maintained in a weighted piston-cylinder assembly at 3 MPa and
250C. Water is slowly heated at constant pressure until the temperature reaches
ME 211
HW #5
4 November 2011
1. Refrigerant 134a at 50C, 1.0 MPa is throttled to 0.2 MPa. Assume no changes in the kinetic
energy.
(1) Find the exit temperature assuming ideal-gas behavior.
(2) Calcul
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HW #6
24 November 2011
1. A rigid tank with the volume of 1 m3 contains air at 500 kPa, 20C. The tank is connected to a line
flowing air at 2 MPa, 20C. The valve is opened, allowing air to flow
ME 211
HW #8
20 December 2011
1. A piston/cylinder contains 2-kg water at 150C, 400 kPa. The piston is slowly moved to expand
the water in an isothermal process to a pressure of 200 kPa. Heat transfer
ME 211
Solution to HW #1
2
1. The acceleration of gravity is 9.80665 m/s . What is the force needed to hold a mass of 3.000 kg
at rest in this gravitational field? How much mass can a force of 2.000 N