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 takes place with an
ambient at 150C and the whole proc
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 and 20C.
Now heat is added to the cylinder.
(1) At what
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 2.000 N support? Write your
answers in 4 significant fig
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 contains saturated vapor
only. Determine the volume of the tan
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 actual heat transfer rate be
higher or lower than this
ME 211
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 is at 100 kPa and 20C.
Now heat is added to the cylind
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 actual heat transfer rate be
higher or lower than this
ME 211
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 350C.
Determine (a) the work required to raise the weighte
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) Calculate the exit temperature for real-gas behavior.
For the
ME 211
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 into the tank until the
pressure reaches 1.5 MPa and i
ME 211
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 350C.
Determine (a) the work required to raise the wei
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) Calculate the exit temperature for real-gas behavior.
2. Stea
ME 211
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 into the tank until the
pressure reaches 1.5 MPa and i
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 takes place with an
ambient at 150C and the whole proc
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 support? Write your
answers in 4 significant figures.