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Unformatted text preview: Assume constant specific heats at room temperature. 5. (4-78) A piston-cylinder device whose piston is resting on top of a set of stops initially contains 0.5 kg of helium gas at 100 kPa and 25 C. The mass of the piston is such that 5000 kPa of pressure is required to raise it. How much heat must be transferred to the helium before the piston starts rising? (A: 1857 kJ) 6. (4-90) Stainless steel ball bearings (density = 8085 kg/m 3 and c p = 0.480 kJ/kG C) having a diameter of 1.2 cm are to be quenched in water at a rate of 800 per minute. The balls leave the oven at a uniform temperature of 900 C and are exposed to air at 25 C for a while before they are dropped into the water. If the temperature of the balls drops to a uniform temperature of 850 C prior to quenching, determine the rate of heat transfer from the balls to the air....
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This note was uploaded on 09/04/2009 for the course CHEM 2300 taught by Professor Thermo during the Summer '08 term at University of Utah.
- Summer '08