Thermodynamics (ES 340) Quiz 1 May 24, 2005 Name: (1 Hour)

Thermodynamics (ES 340) Quiz 1 May 24, 2005Name:(1 Hour)Problem 1 (6 points): A 5-kg piston in a cylinder with diameter of 100 mm is loaded with alinear spring and the outside atmospheric pressure of 100 kPa. The spring exerts no forceon the piston when it is at the bottom of the cylinder and for the state shown, the pressureis 400 kPa with volume 0.4 L. The valve is opened to let some air in, causing the piston torise 2 cm. If the system is assumed to be closed and pressure and volume are linearlyrelated1. Find the pressure when the force from spring is zero (2 points)2. Draw the P-v diagram (2 points)3. Find the final pressure. (2 points)4. (Bonus) Find the spring constant (2 points)Problem 2 (9 points): Water of mass 1 kg at 0.2 MPa is initially enclosed within a volume of0.10 m 3 , and the piston rests on the stops. The piston will move when the pressure is 1.0MPa. A total heat transfer of 2500 kJ is added to the water. The internal energy of the waterat state 1 is 730.96 kJ/kg and it increased due to heat transfer to 1693.5 kJ/kg at state 2. Ifthe specific volume at state 3 is 0.3215 m 3 /kg, determine1. The heat transfer for each process (3 points)2. The work done by each process and the net work (4 points)3. Internal energy of water at state 3. (2 points)

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