A car air-conditioning unit has a 0.5-kg aluminum storage cylinder that is sealed with a valve. It contains 2 L of refrigerant R134a at 500 kPa, and both are at room temperature, 20$^{\circ} \mathrm{C}$. It is now installed in a car sitting outside, where the whole system cools down to ambient temperature at −10$^{\circ} \mathrm{C}$. What is the irreversibility of this process?

R134a is flowed into an insulated 0.2-m3 initially empty container from a line at 500 kPa, saturated vapor until the flow stops by itself. Find the final mass and temperature in the container and the total irreversibility in the process.

A flow of 4 kg/s ammonia goes through a device in a polytropic process with an inlet state of 150 kPa, −20$^{\circ} \mathrm{C}$ and an exit state of 400 kPa, 60$^{\circ} \mathrm{C}$. Find the polytropic exponent n, the specific work, and the heat transfer.

Water at 800$^{\circ} \mathrm{C}$, 15 MPa is flowing through a heat exchanger giving off energy to come out as saturated liquid water at 15 MPa in a steady-flow process. Find the specific heat transfer and the specific flow exergy the water has delivered.

From the experimental evidence that the force between nucleons has a range of about 1 fm, obtain a rough value (in MeV/$c^2$) for the mass of the particle exchanged to convey this force, the pion.

A heat engine receives 5 kW at 800 K and 10 kW at 1000 K, rejecting energy by heat transfer at 600 K. Assume it is reversible and find the power output. How much power could be produced if it could reject energy at T0 = 298 K?

Your friend has just finished classical physics and can’t wait to know what lies ahead. Keeping extraneous ideas and postulates to a minimum, explain the process of quantum-mechanical tunneling.

An aluminum piston of 2.5 kg is in the standard gravitational field, and a force of 25 N is applied vertically up. Find the acceleration of the piston.

A coflowing (same-direction) heat exchanger has one line with 0.25 kg/s oxygen at 17$^{\circ} \mathrm{C}$, 200 kPa entering and the other line has 0.6 kg/s nitrogen at 150 kPa, 500 K entering. The heat exchanger is very long, so the two flows exit at the same temperature. Use constant heat capacities and find the exit temperature.

Bob is watching Anna fly by in her new high-speed plane, which Anna knows to be 60 m in length. As a greeting, Anna turns on two lights simultaneously, one at the front and one at the tail. According to Bob, the lights come on at different times, 40 ns apart. (a) Which comes on first? (b) How fast is the plane moving?

Using a beam of electrons accelerated in an X-ray tube, we wish to knock an electron out of the K shell of a given element in a target, the energies in a hydrogenlike atom as $Z^{2}\left(-\frac{13.6 \mathrm{eV}}{n^{2}}\right).$ Assume that for fairly high Z, a K-shell electron can be treated as orbiting the nucleus alone, (a) A typical accelerating potential in an X-ray tube is 50 kV. In roughly how high a Z could a hole in the AT-shell be produced? (b) Could a hole be produced in elements of higher Z?

A mass of 6 lbm nitrogen gas at 3600 R, V = C, cools with 1 Btu/s. What is dT/dt?

A cylindrical gas tank 3 ft long, with an inside diameter of 8 in., is evacuated and then filled with carbon dioxide gas at 77 F. To what pressure should it be charged if there should be 2.6 lbm of carbon dioxide?

Determine the phase and the missing properties.a. H2O 20$^{\circ} \mathrm{C}$, v = 0.001000 m3/kg P = ?, u = ?b. R-410a 400 kPa, v = 0.075 m3/kg T = ?, u = ?c. NH3 10$^{\circ} \mathrm{C}$, v = 0.1 m3/kg P = ?, u = ?d. N2 101.3 kPa, h = 60 kJ/kg T = ?, v = ?