A piston/cylinder setup contains 1 kg of air at 20°C with an initial volume of V1=0.1 m, as shown in Fig. Q7. Initially, the piston rests on some stops, but it is possible for it to move within the cylinder without friction. To lift the piston and start such motion, an air pressure of 1400 kPa is required. Now, heat is transferred to the system so that the temperature c the air reaches to a final value of 300°C. Piston Air Fig 07

b. Two cylinders are filled with liquid water (p = 998 kg/m³), and connected by a pipe line with a closed valve. Cylinders A (inside diameter = 42.75 cm) and B (inside diameter = 55 cm) contain 125 kg and 450 kg of water, respectively. The height h as indicated in Fig. 3 is 0.85 m. Determine the pressure (in kPa) of cylinder A and cylinder B on either side of the valve. If the valve is opened such that water flows to an equilibrium between the two cylinders, find the final pressure (in atm) at the valve location. Assume Po= 100 kPa. k Po B g Figure 3 Po A

Refrigerant 134a expands in a piston-cylinder assembly from p₁= 200 lb/in² and T₁ = 140°F to p₂ = 30 lb/in² and T₂ = 80 °F. The mass of refrigerant is 0.46 lb. During the process, the work done by the refrigerant is 4.32 Btu. Kinetic and potential energy effects are negligible. Determine the initial volume of the refrigerant, V₁, in ft³, and the heat transfer for the process, in Btu. Step 1 * Your answer is incorrect. Determine the initial volume of the refrigerant, V₁, in ft³. V₁= 0.105743 ft3

A system receives 42 kJ of heat while expanding with volume change of 0.123 m3 against an atmosphere of 12 N/cm2. A mass of 80 kg in the surroundings is also lifted through a distance of 6 metres. (i) Find the change in energy of the system. (ii) The system is returned to its initial volume by an adiabatic process which requires 100 kJ of work. Find the change in energy of system. (iii) Determine the total change in energy of the system.