A Carnot vapor refrigeration cycle employs Refrigerant $134 a$ as the working fluid. The refrigerant enters the condenser as saturated vapor at $28^{\circ} \mathrm{C}$ and leaves it as a saturated liquid. The evaporator operates at a temperature of $-10^{\circ} \mathrm{C}$. Find, in $\mathrm{kJ}$ per $\mathrm{kg}$ of refrigerant flow,

(a) the work input to the compressor.

(b) the work developed by the turbine.

(c) the heat transfer to the refrigerant passing via the evaporator. What is the coefficient of performance of the cycle?

In a poll conducted by The New York Times and CBS News, $44 \%$ of Americans approve of the job that the Supreme Court is doing (The New York Times, June 8, 2012). Assume that at the time of the poll, this percentage applied to the entire American population. A recent survey of 1300 Americans found that $39\%$ of them are satisfied with the Supreme Court's performance. Can you draw the conclusion that the present percentage of Americans who approve of the job the Supreme Court is doing is different from $.44$ at a significance level of $2\%$t?

A refrigerator uses refrigerant-134a as the working fluid and operates on an ideal vapor-compression refrigeration cycle between $0.12$ and for a condenser pressure of $0.9 \mathrm{MPa}$. The mass flow rate of the refrigerant is $0.05 \mathrm{~kg} / \mathrm{s}$. Show the cycle on a $T$-$s$ diagram with respect to saturation lines. Find $(a)$ the rate of heat removal from the refrigerated space and the power input to the compressor, $(b)$ the rate of heat rejection to the environment, and $(c)$ the coefficient of performance.

Match the plot with the description of the sample.

$$\begin{array}{l|l} 6 & 78 \\ 7 & 455888 \\ 8 & 1355889 \\ 9 & 00024 \end{array}$$

Key: $6 \mid 7=67$

a) Time (in minutes) it takes a sample of employees to drive to work

b) Grade point averages of a sample of students with finance majors

c) Top speeds (in miles per hour) of a sample of high-performance sports cars

d) Ages (in years) of a sample of residents of a retirement home

For the cycle of Problem, investigate the effects on cycle performance as the higher extraction pressure takes on other values. The operating conditions for the open feedwater heater are unchanged from those in earlier problem. Assume that condensate drains from the closed feedwater heater as saturated liquid at the higher extraction pressure. Also feedwater leaves the heater at $12\ \mathrm{MPa}$ and a temperature equal to the saturation temperature at the extraction pressure. Construct suitable plots and discuss.

Suppose a Brayton engine is run as a refrigerator. In this case, the cycle begins at temperature $T_1$, and the gas is isobarically expanded until it reaches temperature $T_4$. Then the gas is adiabatically compressed, until its temperature is $T_{3^{-}}$. It is then isobarically compressed, and the temperature changes to $T_2$. Finally, it is adiabatically expanded until it returns to temperature $T_1$. a) Sketch this cycle on a $p V$-diagram. b) Show that the coefficient of performance of the engine is given by $K=\left(T_4-T_1\right) /\left(T_3-T_2-T_4+T_1\right)$.

Consider a Carnot-cycle heat pump with R22 as the working fluid; Heat is rejected from the R-22 at 100 F: during which process the R-22 changes from saturated vapor to saturated liquid. The heat is transferred to the R-22 at 30 F. a. Show the cycle on a T-diagram. b. Find the quality of the R-22 at the beginning and end of the isothermal heat addition process at 30 F. c. Determine the coefficient of performance for the cycle.

A window air conditioner that consumes 1 kW of electricity when running and has a coefficient of performance of 3 is placed in the middle of a room, and is plugged in. The rate of cooling or heating this air conditioner will provide to the air in the room when running is (a) 3 kJ/s, cooling (b) 1 kJ/s, cooling (c) 0.33 kJ/s, heating (d) 1 kJ/s, heating (e) 3 kJ/s, heating

Performance of stock screeners. Refer to the American Association of Individual Investors (AAII) statistics on stock screeners, Exercise $2.44$ (p. 71). Annualized percentage return on investment (as compared to the Standard & Poor's 500 Index) for 13 randomly selected stock screeners are reproduced in the table. Find the range of the data for the 13 stock screeners. Give the units of measurement for the range.

Performance data for a centrifugal fan of 3-ft diameter, tested at 750 rpm, are

$$\begin{matrix} \text{Volume flow rate Q (}{\mathrm{ft}^{3} /s)} & \text{106} & \text{141} & \text{176} & \text{211} & \text{246} & \text{282}\\ \text{Static pressure rise, }{\Delta p} (psi) & \text{0.075} & \text{0.073} & \text{0.064} & \text{0.050} & \text{0.033} & \text{0.016}\\ \text{Power output }{\mathscr{P} (hp)} & \text{2.75} & \text{3.18} & \text{3.50} & \text{3.51} & \text{3.50} & \text{3.22}\\ \end{matrix}$$

Plot the performance data versus volume flow rate. Calculate static efficiency, and show the curve on the plot. Find the best efficiency point, and specify the fan rating at this point. Using the fan, determine the minimum size square sheet-metal duct that will carry a flow of 200 $\mathrm{ft}^{3}$/s over a distance of 50 ft. Estimate the increase in delivery if the fan speed is increased to 1000 rpm.

Peal Corporation issued 4,000 shares of its $10 par value stock with a market value of$85,000 to acquire 85 percent of the common stock of Seed Company on August 31, 20X3. Seed's fair value was determined to be $100,000 on that date. Peal had previously purchased 15 percent of Seed's common stock for$9,000 on January 31, 20X1, and had carried this investment at fair value on its balance. Peal reported this investment at $15,000 on its balance sheet at August 31, 20X3, immediately prior to acquiring the remaining 85 percent of Seed's shares. On August 31, 20X3, Peal also paid appraisal fees of$3,500 and stock issue costs of $2,000 incurred in completing the acquisition of the additional shares.

Required

Give the journal entries to be recorded by Peal in completing the acquisition of the additional shares of Seed.

True or false: (a) Work can never be converted completely into heat. (b) Heat can never be converted completely into work. (c) All heat engines have the same efficiency. (d) It is impossible to transfer a given quantity of heat from a cold reservoir to a hot reservoir. (e) The coefficient of performance of a refrigerator cannot be greater than 1. (j) All Carnot engines are reversible. (g) The entropy of a system can never decrease. (h) The entropy of the universe can never decrease.

The following performance scores have been recorded for 25 job applicants who have taken a preemployment aptitude test administered by the company to which they applied:

$$\begin{array}{rrrrrrrrr}66.6 & 75.4 & 66.7 & 59.2 & 78.5 & 80.8 & 79.9 & 87.0 & 94.1 \\ 70.2 & 92.8 & 86.9 & 92.8 & 66.8 & 65.3 & 100.8 & 76.2 & 87.8 \\ 71.0 & 92.9 & 97.3 & 82.5 & 78.5 & 72.0 & 76.2 & & \end{array}$$

Construct a frequency distribution and a histogram for these data.

Flynn Industries has outsourced the delivery of its products and now wants to develop a tool to help evaluate its transportation carriers. The table at the bottom of the page shows the rating values associated with different levels of price, quality, and delivery performance, as well as criteria weights that reflect the relative importance of these dimensions. To illustrate how the ratings work, suppose a carrier has a damage level of 0.82%. This would fall between 0.75% and 1.0%, thereby garnering a rating of 2. The second table shows actual average performance levels for three carriers.

a. Use the weighted-point evaluation system to calculate the weighted average performance for each carrier. Which carrier is best under this system?

b. How would the results change if the weights for price, quality, and delivery shifted to 0.6, 0.2, and 0.2, respectively?

c. Based on the results, should Flynn Industries single source or not? What might stop Flynn from single sourcing?