University Physics (14th Edition)
14th Edition
ISBN: 9780133969290
Author: Hugh D. Young, Roger A. Freedman
Publisher: PEARSON
expand_more
expand_more
format_list_bulleted
Videos
Textbook Question
Chapter 20, Problem 20.55P
DATA In your summer job with a venture capital firm, you are given funding requests from four inventors of
| Prototype | ||||
| A | B | C | D | |
| TC (°C), low-temperatu re reservoir | 47 | 17 | –33 | 37 |
| TH (°C). high-t emperatu re reservoir | 177 | 197 | 247 | 137 |
| Claimed efficiency e (% ) | 21 | 35 | 56 | 20 |
(a) Based on the TC and TH values for each prototype, find the maximum possible efficiency for each. (b) Are any of the claimed efficiencies impossible? Explain. (c) For all prototypes with an efficiency that is possible, rank the prototypes in decreasing order of the ratio of claimed efficiency to maximum possible efficiency.
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
In your summer job with a venture capital firm, you are given
funding requests from four inventors of heat engines. The
inventors claim the following data for their operating prototypes:
Prototype
ABCD
Tc (°C), low-temperature reservoir 47 17 -33 37
TH (°C), high-temperature reservoir 187 217 277 147
Claimed efficiency e (%)
20 38 60 22
Submit
✓ Correct
Part D
Previous Answers
Based on the Tc and TH values for prototype D, find its maximum possible efficiency.
emax D = 26 %
Submit
Part E
Previous Answers
✓ Correct
Are any of the claimed efficiencies impossible?
Check all that apply.
✔Prototype A
✔Prototype B
✔ Prototype C
O Prototype D
Submit Previous Answers Request Answer
X Incorrect; Try Again; 2 attempts remaining
Review | Com
For bacteriological testing of water supplies and in medical clinics, samples must routinely be incubated for 24 h at 37°C. A standard constant-temperature bath with electric heating and thermostatic control is not suitable in developing nations without continuously operating electric power lines. Peace Corps volunteer and MIT engineer Amy Smith invented a low-cost, lowmaintenance incubator to fill the need. The device consists of a foam-insulated box containing several packets of a waxy material that melts at 37.0°C, interspersed among tubes, dishes, or bottles containing the test samples and growth medium (food for bacteria). Outside the box, the waxy material is first melted by a stove or solar energy collector. Then it is put into the box to keep the test samples warm as it solidifies. The heat of fusion of the phase-change material is 205 kJ/kg. Model the insulation as a panel with surface area 0.490 m2, thickness 9.50 cm, and conductivity 0.012 0 W/m°C. Assume the exterior…
A piston–cylinder device initially contains 0.5 m3 of nitrogen gas at 400 kPa and 27°C. An electric heater within the device is turned on and is allowed to pass a current of 2 A for 5 min from a 120-V source. Nitrogen expands at constant pressure, and a heat loss of 2800 J occurs during the process. Determine the final temperature of nitrogen.
Chapter 20 Solutions
University Physics (14th Edition)
Ch. 20 - A pot is half-filled with water, and a lid is...Ch. 20 - Prob. Q20.2DQCh. 20 - Prob. Q20.3DQCh. 20 - Prob. Q20.4DQCh. 20 - Why must a room air conditioner be placed in a...Ch. 20 - Prob. Q20.6DQCh. 20 - Prob. Q20.7DQCh. 20 - An electric motor has its shaft coupled to that of...Ch. 20 - When a wet cloth is hung up in a hot wind in the...Ch. 20 - Compare the pV-diagram for the Otto cycle in Fig....
Ch. 20 - The efficiency of heat engines is high when the...Ch. 20 - What would be the efficiency of a Carnot engine...Ch. 20 - Real heat engines, like the gasoline engine in a...Ch. 20 - Does a refrigerator full of food consume more...Ch. 20 - How can the thermal conduction of heat from a hot...Ch. 20 - Explain why each of the following processes is an...Ch. 20 - The free expansion of an ideal gas is an adiabatic...Ch. 20 - Are the earth and sun in thermal equilibrium? Are...Ch. 20 - Prob. Q20.20DQCh. 20 - Prob. Q20.21DQCh. 20 - Prob. Q20.22DQCh. 20 - BIO A growing plant creates a highly complex and...Ch. 20 - A diesel engine performs 2200 J of mechanical work...Ch. 20 - An aircraft engine takes in 9000 J of heat and...Ch. 20 - A Gasoline Engine. A gasoline engine takes in 1.61...Ch. 20 - A gasoline engine has a power output of 180 kW...Ch. 20 - The pV-diagram in Fig. E20.5 shows a cycle of heat...Ch. 20 - (a) Calculate the theoretical efficiency for an...Ch. 20 - The Otto-cycle engine in a Mercedes-Benz SL1 a...Ch. 20 - Section 20.4 Refrigerators 20.8The coefficient of...Ch. 20 - A refrigerator has a coefficient of performance of...Ch. 20 - A freezer has a coefficient of performance of...Ch. 20 - A refrigerator has a coefficient of performance of...Ch. 20 - A Carnot engine is operated between two heat...Ch. 20 - A Carnot engine whose high-temperature reservoir...Ch. 20 - An ice-making machine operates in a Carnot cycle....Ch. 20 - A Carnot engine has an efficiency of 66% and...Ch. 20 - A certain brand of freezer is advertised to use...Ch. 20 - A Carnot refrigerator is operated between two heat...Ch. 20 - A Carnot heat engine uses a hot reservoir...Ch. 20 - You design an engine that takes in 1.50 104 J of...Ch. 20 - A 4.50-kg block of ice at 0.00C falls into the...Ch. 20 - A sophomore with nothing better to do adds heat to...Ch. 20 - CALC You decide to take a nice hot bath but...Ch. 20 - A 15.0-kg block of ice at 0.0C melts to liquid...Ch. 20 - CALC You make tea with 0.250 kg of 85.0C water and...Ch. 20 - Three moles of an ideal gas undergo a reversible...Ch. 20 - What is the change in entropy of 0.130 kg of...Ch. 20 - (a) Calculate the change in entropy when 1.00 kg...Ch. 20 - Entropy Change Due to Driving. Premium gasoline...Ch. 20 - CALC Two moles of an ideal gas occupy a volume V....Ch. 20 - A box is separated by a partition into two parts...Ch. 20 - CALC A lonely party balloon with a volume of 2.40...Ch. 20 - You are designing a Carnot engine that has 2 mol...Ch. 20 - CP An ideal Carnot engine operates between 500C...Ch. 20 - Prob. 20.34PCh. 20 - CP A certain heat engine operating on a Carnot...Ch. 20 - A heat engine takes 0.350 mol of a diatomic ideal...Ch. 20 - Prob. 20.37PCh. 20 - What is the thermal efficiency of an engine that...Ch. 20 - CALC You build a heal engine that takes 1.00 mol...Ch. 20 - CP As a budding mechanical engineer, you are...Ch. 20 - CALC A heal engine Operates using the cycle shown...Ch. 20 - CP BIO Humun Entropy. A person who has skin of...Ch. 20 - An experimental power plant at the Natural Energy...Ch. 20 - CP BIO A Human Engine. You decide to use your body...Ch. 20 - CALC A cylinder contains oxygen at a pressure of...Ch. 20 - A monatomic ideal gas it taken around the cycle...Ch. 20 - A Carnot engine operates between two heat...Ch. 20 - A typical coal-fired power plant generates 1000 MW...Ch. 20 - Automotive Thermodynamics. A Volkswagen Passat has...Ch. 20 - An air conditioner operates on 800 W of power and...Ch. 20 - The pV-diagram in Fig. P20.51 shows the cycle for...Ch. 20 - BIO Human Entropy. A person with skin of surface...Ch. 20 - CALC An object of mass m1, specific heat c1, and...Ch. 20 - CALC To heat 1 cup of water (250 cm3) to make...Ch. 20 - DATA In your summer job with a venture capital...Ch. 20 - DATA For a refrigerator or air conditioner, the...Ch. 20 - DATA You are conducting experiments to study...Ch. 20 - Consider a Diesel cycle that starts (at point a in...Ch. 20 - POWER FROM THE SEA. Ocean thermal energy...Ch. 20 - POWER FROM THE SEA. Ocean thermal energy...Ch. 20 - POWER FROM THE SEA. Ocean thermal energy...Ch. 20 - POWER FROM THE SEA. Ocean thermal energy...
Additional Science Textbook Solutions
Find more solutions based on key concepts
Testing Relativity. A π+ meson produced at rest has a lifetime of 18 nanoseconds (1.8 × 10−8 s). Thus, in its o...
Life in the Universe (4th Edition)
3. What is free-fall, and why does it make you weightless? Briefly describe why astronauts are weightless in th...
The Cosmic Perspective
66. Astronauts use a centrifuge to simulate the acceleration of a rocket launch. The centrifuge takes 30 s to...
Physics for Scientists and Engineers: A Strategic Approach, Vol. 1 (Chs 1-21) (4th Edition)
Answer the following questions for the position of the Moon shown in Figure 1.
Which Moon phase would an Earth...
Lecture- Tutorials for Introductory Astronomy
Are household electrical outlets connected in series or parallel? How do you know?
Essential University Physics: Volume 2 (3rd Edition)
The pV-diagram of the Carnot cycle.
Sears And Zemansky's University Physics With Modern Physics
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, physics and related others by exploring similar questions and additional content below.Similar questions
- An insulated 8-m3 rigid tank contains air at 600 kPa and 400 K. A valve connected to the tank is now opened, and air is allowed to escape until the pressure inside drops to 200 kPa. The air temperature during the process is maintained constant by an electric resistance heater placed in the tank. Determine the electrical energy supplied to air during this process.arrow_forwardCompressed air can be pumped underground into huge caverns as a form of energy storage. The volume of a cavern is 6.3 x 105 m³, 5 and the pressure of the air in it is 7.4 × 106 Pa. Assume that air is a diatomic ideal gas whose internal energy U is given by U = nRT. If one home uses 30.0 kWh of energy per day, how many homes could this internal energy serve for one day?arrow_forwardYou have a spherical heater, outside diameter = 3.40 cm, immersed in a container of water. In order to keep the water in the container heated to a constant temperature of 35.0°C you adjust the temperature of the spherical heater. You reach a steady-state condition when the surface temperature of the spherical heater is at 79.0°C. Assuming the electrical efficiency of the heater is 100.0%, calculate the power required by the heater (i.e., calculate q). Ignore radiation.arrow_forward
- An electric power plant that would make use of temperature gradient in the ocean has been proposed. The system is to operate between 20.0 °C at water surface and 5.00 °C at a depth of 1 km. a) What is the maximum efficiency of the system? b) If useful power output of plant is 75 MW, how much energy is taken in from the warm reservior per hour?arrow_forwardWith the following experimental data, calculate the average ignition temperature and the theoretical minimum ignition heat flux for the following thermally thick material.arrow_forwardP₁ P3 Р V. T₁ 2 T₂ 3 T₁ V V. A heat engine consists of a heat source that causes a monatomic gas to expand, pushing against a piston, there by doing work. The gas begins at a pressure of p₁-300 kPa, a volume of V₁=150 cm³, and room temperature, T₁= 20 °C. On reaching a volume of V₂=450 cm³, the piston is locked in place, and the heat source is removed. At this point the gas cools back to room temperature. Finally, the piston is unlocked and used to isothermally compress the gas back to its initial state. The cycle is shown on the pV-diagram in the figure. Molar heat capacity at constant pressure for monatomic ideal gas is Cp = Cv+ R = 5R/2 where the universal gas constant is R = 8.314 J/mol K) Determine the work done on the gas in the process 2-3. Express your answer in J.arrow_forward
- In a solar water heater, energy from the Sun is gathered by water that circulates through tubes in a rooftop collector.The solar radiation enters the collector through a transparent cover and warms the water in the tubes; this water is pumped into a holding tank. Assume that the efficiency of the overall system is 20% (that is, 80% of the incident solar energy is lost from the system). What collector area is necessary to raise the temperature of 200 L of water in the tank from 20C to 40°C in 1.0 h when the intensity of incident sunlight is 700 W/m2?arrow_forwardSix kilograms of liquid water at 0° C is put into the freezer compartment of a Carnot refrigerator. The temperature of the compartment is -15.3° C, and the temperature of the kitchen is 24.9° C. If the cost of electrical energy is ten cents per kilowatt · hour, how much does it cost to make two kilograms of ice at 0° C?arrow_forwardConsider the operation of an actual turbine in a gas turbine engine. The mass flow rate is 50 lbm/s. The turbine inlet temperature is 2040 deg F. The pressure ratio in the compressor is 18.15. The turbine efficiency is 0.91. Assume variable specific heats. The turbine work output is nearly Group of answer choices 310 B/lbm 340 B/lbm 355 B/lbm 325 B/lbmarrow_forward
- A “solar cooker” consists of a curved reflecting mirror that focuses sunlight onto the object to be heated (Fig. P11.69). The solar power per unit area reaching the Earth at the location of a 0.50-m-diameter solar cooker is 600. W/m2. Assuming 50% of the incident energy is converted to thermal energy, how long would it take to boil away 1.0 L of water initially at 20.°C? (Neglect the specific heat of the container.)arrow_forwardIn many ideal gas problems, room temperature is considered to be at 300 K to make calculations ?easier. What is this temperature in Celsius C = 60° a O C = 66°.bO C = 63°.cCarrow_forwardA piston–cylinder device contains 2.2 kg of nitrogen initially at 100 kPa and 25°C. The nitrogen is now compressed slowly in a polytropic process during which PV 1.3 = constant until the volume is reduced by one-half. Determine the work done and the heat transfer for this process.arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
Principles of Physics: A Calculus-Based TextPhysicsISBN:9781133104261Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning
Principles of Physics: A Calculus-Based Text
Physics
ISBN:9781133104261
Author:Raymond A. Serway, John W. Jewett
Publisher:Cengage Learning
Thermodynamics: Crash Course Physics #23; Author: Crash Course;https://www.youtube.com/watch?v=4i1MUWJoI0U;License: Standard YouTube License, CC-BY