Mechanical Engineering Answers

Two kg of water is contained in a piston-cylinder arrangement by a 16 000-kg, 2-m-diameter, frictionless piston. See Fig. 2-1. Heat is added until the temperature reaches (a) 400 "C, (b)650 "C, and (c) 140 "C. Calculate the final volume. Ans. (a) 4.134 m3 (b)5.678 m3 (c) 2.506 m3

Freon 12 is contained in a sealed glass container at 50°C. As it is cooled, vapor droplets arc noted condensing on the sidewalls at 20°C. Find the original pressure in the container. Arts. 650 kPa

A rigid vessel contains water at 400°F. Heat is to be added so that the water passes through the critical point. What should the quality be at the temperature of 400"F? Am. 0.01728

Steam with a quality of 0.85 is contained in a rigid vessel at a pressure of 200 kPa. Heat is then added until the temperature reaches (a)400 "C and (b)140 "C. Determine the final pressures. Ans. (a) 415 kPa (h)269 kPa
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A rigid vessel with a volume of 10 m3 contains a water-vapor mixture at 400 kPa. If the quality is 60 percent, find the mass. The pressure is lowered to 300 kPa by cooling the vessel; find mKand m,. Am. 35.98 kg. 16.47 kg, 19.51 kg

The temperature of 10 Ib of water is held constant at 205°F. The pressure is reduced from a very high value until vaporization is complete. Determine the final volume of the steam. Ans. 307.2 ft'

Two kg of saturated water at 125 kPa is completely vaporized. Calculate the volume (a)before and (b) after. Ans. (a)0.002 m3 (b)2.76 m3

Determine the final volume of a mixture of water and steam if 3 kg of water is heated at a constant pressure until the quality is 60 percent. The pressure is (a)25 kPa and (b)270 kPa.
Ans. (a) 11.6 mZ (h)1.24 m3

The quality of each of the following substances is 80%. Calculate the specific volume. (a)Water at 500 psia; (h)Freon 12 at 80 psia; (c)ammonia at 20°F. Am. (U) 0.7366 ft3/Ibm (h)0.4078 ft3/Ibm (c)4.733 ft3/lbm

Calculate the specific volume for the following situations: (U) water at 200"C, 80% quality; (h)Freon 12 at -60°C, 90% quality; ((8) ammonia at 500 kPa, 8S% quality. Am. (a)0.1022 mZ/ kg (b)0.5736 m3/ kg (c)0.2133 m'/ kg