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.

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.

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?

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?

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.

A compressor brings nitrogen from 100 kPa, 290 K to 2000 kPa. The process has a specific work input of 450 kJ/kg and the exit temperature is 450 K. Find the specific heat transfer using constant specific heats.

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 = ?

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?

A speedboat has a small hole in the front of the drive with the propeller that extends down into the water at a water depth of 15 in. Assume we have a stagnation point at that hole when the boat is sailing at 30 mi/h; what is the total pressure there?

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

Jellyfish Machine Shop is a manufacturer of motorized carts for vacation resorts. Patrick Cullin, the plant manager of Jellyfish, obtains the following information for Job #10 in August 2017. A total of 46 units were started, and 6 spoiled units were detected and rejected at final inspection, yielding 40 good units. The spoiled units were considered to be normal spoilage. Costs assigned prior to the inspection point are $1,100 per unit. The current disposal price of the spoiled units is$235 per unit. When the spoilage is detected, the spoiled goods are inventoried at $235 per unit. 1. What is the normal spoilage rate? 2. Prepare the journal entries to record the normal spoilage, assuming the following: a. The spoilage is related to a specific job. b. The spillage is common to all jobs. c. The spoilage is considered to be abnormal spoilage.

There are more permutations of particle labels when two particles have energy 0 and two have energy 1 than when three particles have energy 0 and one has energy 2. (The total energies are the same,) From this observation alone argue that the Boltzmann distribution should be lower than the Bose-Einstein at the lowest energy level.

MRI relies on only a tiny majority of the nuclear magnetic moments aligning with the external field. Consider the common target nucleus hydrogen. The difference between the aligned and antialigned states of a dipole in a magnetic field is $2 \mu_z B,$ provided that the correct mass and gyromagnetic ratio (gp - 5.6) are inserted. Using the Boltzmann distribution, show that for a 1.0 T field and a reasonable temperature, the number aligned exceeds the number antialigned by less than $\frac{1}{1000}$ %.

What is visible light? How does it differ from the other forms of electromagnetic radiation?