A closed system of mass 5 lb undergoes a process in which there is a heat transfer of 200 ft-lbf from the system to the surroundings. There is no work during the process. The velocity of the system changes from 10 ft/s to 50 ft/s, and the elevation decreases by 150 ft. The acceleration of gravity is 32.0 ft/s². Determine change in internal energy of the system, in ft-lbf and Btu.
A gas expands from an initial state where the pressure is 340 kPa and the volume is 0.0425 m³ to a final state where the pressure is 136 kPa. The relationship between the pressure and volume of the gas during the process is pV²=constant. Sketch the process on p-V diagram and determine the work, in kJ.
A gas in a piston-cylinder assembly undergoes two processes in series. From state 1 to state 2 there is energy transfer by heat to the gas with a magnitude of 800 kJ. The second process, from state 2 to state 3, is constant-pressure compression at 400 kPa during which there is a heat transfer from the gas with a magnitude of 450 kJ. The following data are also known: U2 = 2000 kJ and U3 =3500 kJ. Neglecting changes in in kinetic and potential energy, calculate the change in volume of the gas during process 2-3, in m³.
A gas in a piston-cylinder assembly is compressed from p1 = 3.4 bar. V1 = 0.0283 m³ to p2 = 8.2bar in a process for which the relation between pressure and volume is pV¹ ² = constant. The mass of the gas is 0.183 kg. During the process, the heat transfer from the gas is 2.2 kJ. Determine the change in specific internal energy of the gas, in kJ/kg. Kinetic and potential energy effects are negligible.
A gas undergoes a thermodynamic cycle consisting of three process beginning at an initial state where p1 = = 1 bar,
V1 = 1.5 m³, and U1 = 512 kJ. The processes are as follows:
Process 1-2: compression with pV = constant to p2 = 2 bar, U2 = 690kJ
Process 2-3: W2.3 = 0, Q23 = -150 kJ
Process 3-1: W31 = +50 kJ
There is no significant changes in kinetic or potential energy. Determine the heat transfers Q12 and Q31, each in kJ.