• 2-40 Water is being heated in a closed pan on top of a range while being stirred by a paddle wheel. During the process, 30 kJ of heat is transferred to the water, and 5 kj of heat is lost to the surrounding air. The paddle-wheel work amounts to 500 N:m. Determine the final energy of the system if its initial energy is 12.5 kJ.

A rigid 10-L vessel initially contains a mixture of liquid water and vapor at 100° C with 12.3 percent quality. The mixture is then heated until its temperature is 150° C. Calculate the heat transfer required for this process in kJ.

3.19. An ideal gas initially at 600 K and 10 bar undergoes a four-step mechanically reversible cycle in a closed system. In step 12, pressure decreases isothermally to 3 bar; instep 23. pressure decreases at constant volume to 2 bar; in step 34, volume decreases at constant pressure; and in step 41, the gas returns adiabatically to its initial state.Take Cp = (7/2)R and Cy = (5/2)R. (a) Sketch the cycle on a PV diagram. (b) Determine (where unknown) both T and P for states 1, 2, 3, and 4. \text { (c) Calculate } Q, W, \Delta U, \text { and } \Delta H \text { for each step of the cycle. }

4) Refrigerant-134a enters the condenser of a residential heat pump at 800 kPa and 35°C at a rate of 0.018 kg/s and leaves atS00 kPa as a saturated liquid. If the compressor consumes 1.2 kW of power, determine (a) the COP of the heat pump and(b) the rate of heat absorption from the outside air.

2. (1-62) A mercury manometer (p = 13,600 kg/m') is connected to an air duct to measure the pressure inside. The difference in the manometer levels is 15 mm, and the atmospheric pressure is 100kPa. a. Answer in one sentence: Judging from figure below,determine if the pressure in the duct is above or below the atmospheric pressure. (Points 2) b. Determine the absolute pressure in the duct. (Points 7)

An oil pump is drawing 35 kW of electric power while pumping oil with p= 860 kg/m³ at a rate of 0.1 m³/s. The inlet and outlet diameters of the pipe are 8 cm and 12 cm, respectively. If the pressure rise of oil in the pump is measured to be 400 kPa and the motor efficiency is 90 percent,determine the mechanical efficiency of the pump.

4-63 A rigid tank initially contains 1.4-kg saturated liquid water at 200°C. At this state, 25 percent of the volume is occupied by water and the rest by air. Now heat is supplied to the water until the tank contains saturated vapor only. Determine (a) the volume of the tank, (b) the final temperature and pressure, and (c) the internal energy change of the water.

A rigid tank contains 50 kg of saturated liquid water at 90°C. Determine thepressure (kPa) in the tank and the volume (m³) of the tank. A piston-cylinder device contains 2 ft3 of saturated water vapor at 50 psiapressure. Determine the temperature (°F) and mass (Ibm) of the vaporinside the cylinder. Determine the specific internal energy (kJ/kg) of water at 50 kPa and 200°С. Refrigerant-134a at 200 kPa and 20°C flows through a refrigeration line.Determine its specific volume (m³/kg) The temperature in a pressure cooker during cooking at sea level is measured to be 250°F. Determine the absolute pressure inside the cooker in psia and atm.

2–62 The water in a large lake is to be used to generate electricity by the installation of a hydraulic turbine-generator at a location where the depth of the water is 50 m. Water is to be supplied at a rate of 5000 kg/s. If the electric power generated is measured to be 1862 kW and the generator efficiency is95 percent, determine (a) the overall efficiency of the turbine–generator, (b) the mechanical efficiency of the turbine, and(c) the shaft power supplied by the turbine to the generator.

HW2- Determine the power required for a 1150-kg car to climb a 100-m-long uphill road with a slope of 30° (from horizontal) in 12 s (a) at a constant velocity, (b) from rest to a final velocity of 30 m/s, and (c) from 35 m/s to a final velocity of 5 m/s. Disregard friction, air drag, and rolling resistance.