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1. The stored energy of a closed system decreases by 5kJ while 50kJ of work done on to it.Determine the amount of heat transfer associated with this process.

2. A frictionless piston cylinder system has 150kPa initial pressure of air in the cylinder.The piston is held in position by an external force F acting on the piston. The initialvolume of 0.05 cubic meters is doubled by slowly reducing the external force, allowingthe gas to expand. The expansion is found to obey the rule that the pressure is inverselyproportional to volume. Find the work done by the expansion of air.

3. Nitrogen gas at 300K, 101kPa and 0.1 cubic meters is compressed slowly in anisothermal process to 500kPa. Calculate the work done during the process.

4. During the charging of a storage battery, the current is 20 ampere and the voltage is12V.The rate of heat transfer from the battery is 12W. Determine the net rate of increase

in the internal energy of the battery.

5. A spherical balloon contains 5kg of air at 200kPa and 500K. The pressure inside theballoon is always proportional to the square of the diameter. Determine the work donewhen the volume of the balloon doubles as a result of heat transfer. Also, determine thefinal temperature.

6. A small turbine working under the following conditions runs an aircraft refrigerationunit. Air at 4 bar and 313K flows steadily into the turbine at 40m/s. at the turbine exit,the condition of the air is 1 bar, 275.5K and 200m/s. the shaft work delivered by the

turbine is 52kJ/kg of air. Determine the heat transfer per kg of air flowing through theturbine.

7. A reciprocating air compressor takes 0.05 of air at 101kPa and 25 and delivers itat 150kPa and 120 to an after cooler, where the air is cooled at constant pressure to30 . The power supplied to the compressor is 5kW. Determine the heat transfer incompressor and after cooler.

8. Air is compressed adiabatically in a piston-cylinder device from 15 and 101kPa to300 in reversible manner. Determine the compression ratio of the piston-cylinderdevice.

9. A piston cylinder device contains 0.8kg of an ideal gas. Now, the gas is cooled atconstant pressure until its temperature decreases by 10 . If 16.6kJ of compression workis done during this process, determine the gas constant and the molar mass of the gas.Also, determine the constant volume and constant pressure specific heats of the gas if itsspecific heat ratio is 1.667.

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10. In a manufacturing facility, 5 cm diameter brass balls (

initially at 120 are quenched in a water bath at 50 for a period of 2min at a rate of 100 balls per minute. If the temperature of the balls after quenching is74 , determine the rate at which heat needs to be removed from the water in order tokeep its temperature at 50 .

11. An automobile tube has a constant volume of 0.08 . While driving on a hot road, thetube picks up heat energy at a rate of 0.6 . Calculate the number of kilometers to bedriven so that the pressure inside the tube rises to 200kPa, if the initial pressure andtemperature of the air inside the tube are 165kPa and 310K, respectively.

12. At the end of the exhaust stroke of an internal combustion engine, the combustionchamber is filled with 0.10g of exhaust gases at 700K and 101kPa. The piston then travelsout on the intake stroke, inducting 2g of air at 293K and 101kPa. Neglecting any heattransfer associated with this process, determine the pressure and temperature of themixture at the end of the intake stroke.

13. Air flows steadily through a rotary compressor. At the entry, the air is at 20 and101kPa and at the exit at 200 and 600kPa. Assume the flow to be adiabatic

i. Evaluate the work done per unit mass of air assuming the velocities at the entry and exitto be negligible.

ii. Estimate the increase in work input required if the velocities at the inlet and exit are50m/s and 110m/s , respectively.