An insulated piston-cylinder device contains 0.15 m of saturated refrigerant-134a vapor at 0.8 mpa pres- sure. the refrigerant is now allowed to expand in a reversible manner until the pressure drops to 0.2 mpa. determine the change in the exergy of the refrigerant during this process and the reversible work. assume the surroundings to be at 25° c and 100 kpa.

Ariver flows from north to south at 8 km/h. a boat is to cross this river from west to east at a speed of 20 km/h (speed of the boat with respect to the earth/ground). at what angle (in degrees) must the boat be pointed upstream such that it will proceed directly across the river (hint: find the speed of the boat with respect to water/river)? a 288 b. 21.8 c. 326 d. 30.2

Manometers are good examples of measuring instruments, nowadays they are not as common as before. a)-capacitive probe gauges b)-gravitational gauges deformation ) gauges d)-digital gauges

The flow rate of air through a through a pipe is 0.02 m5/s. a pitot static tube is placed in the flow. the radius of the pitot static tube is 1 mm. assuming the flow to be steady and the air to be at 300k, calculate the difference in total and static pressure if the diameter of the pipe is: (a) d 0.1 m d 0.05 m (c) d 0.01 m