Wright State University

Wright State University ME 315, Fall 2005 Department of Mechanical and Materials Engineering

MIDTERM TEST 1: OPEN BOOK, CLOSED NOTES

1. (20 points) A water pipe is connected to a double-U manometer as shown at a location where the local atmospheric pressure is 14.2 psia. Determine the absolute pressure at the center of the pipe.

2. (20 points) The pressure of an automobile tire is measured to be 200 kPa (gage) before a trip and 220 kPa (gage) after the trip at a location where the atmospheric pressure is 90 kPa. If the temperature of the air in the tire before the trip is 25ºC, determine the air temperature after the trip. 3. (20 points) A sealed volume of 2.0 cm3 contains saturated water. The container is heated from an initial pressure of 0.10 MPa until the vessel contains a single phase. Determine the final state (phase and temperature) of the water if the vessel contains (a) 0.10 g and (b) 1.0 g. 4. (40 points) A piston encloses 0.5 lbm of saturated water which is initially 10.0 percent liquid on a mass basis. The initial pressure is 150 psia. The water is heated in the system shown in the figure until the water is at the saturated vapor state. The volume at the top stops is 1.5 ft3. Determine the work done by the water and the final temperature and pressure. Draw the process on a P-v diagram with respect to saturation lines.