
Physics for Scientists and Engineers
10th Edition
ISBN: 9781337553278
Author: Raymond A. Serway, John W. Jewett
Publisher: Cengage Learning
expand_more
expand_more
format_list_bulleted
Textbook Question
Chapter 21.2, Problem 21.2QQ
The energy entering an electric heater by electrical transmission can be converted to internal energy with an efficiency of 100%. By what factor does the cost of heating your home change when you replace your electric heating system with an electric heat pump that has a COP of 4.00? Assume the motor running the heat pump is 100% efficient. (a) 4.00 (b) 2.00 (c) 0.500 (d) 0.250
Expert Solution & Answer

Trending nowThis is a popular solution!

Students have asked these similar questions
Draw a right-handed 3D Cartesian coordinate system (= x, y and z axes). Show a vector A with
tail in the origin and sticking out in the positive x, y and z directions. Show the angles between A
and the positive x, y and z axes, and call these angles α₁, α₂ and α3
Prove that Ax Acos α₁
Ay
= Acos α₂
A₂- Acos α3
solve for Vo
Draw a third quadrant vector C. (remember that boldface characters represent vector
quantities). Show the standard angle 0 for this vector (= angle that C makes with the positive x-
axis). Also show the angle that C makes with the negative y-axis: call the latter angle 8. Finally,
show the smallest angles that C makes with the positive x-axis and the positive y-axis: call these
angles p1 and p2, repectively.
a) Prove the following formulas for the components of C involving the standard angle (hint:
start with the formulas for the components based on the angle & and then use (look up if
necessary) co-function identities linking cosine and sine of 8 to sine and cosine of 0 since 8 =
3π/2-8 (this will switch cosine and sine around and eliminate - signs as well))
-
C=Ccose
C₁=Csine
b) Prove the following formulas for the components of C:
C=Ccosp1
C=Ccosp2
Chapter 21 Solutions
Physics for Scientists and Engineers
Ch. 21.1 - The energy input to an engine is 4.00 times...Ch. 21.2 - The energy entering an electric heater by...Ch. 21.4 - Three engines operate between reservoirs separated...Ch. 21.6 - (a) Suppose you select four cards at random from a...Ch. 21.7 - An ideal gas is taken from an initial temperature...Ch. 21.7 - True or False: The entropy change in an adiabatic...Ch. 21 - A particular heat engine has a mechanical power...Ch. 21 - The work done by an engine equals one-fourth the...Ch. 21 - Suppose a heat engine is connected to two energy...Ch. 21 - During each cycle, a refrigerator ejects 625 kJ of...
Ch. 21 - A freezer has a coefficient of performance of...Ch. 21 - A heat pump has a coefficient of performance equal...Ch. 21 - One of the most efficient heat engines ever built...Ch. 21 - Why is the following situation impossible? An...Ch. 21 - If a 35.0% -efficient Carnot heat engine (Fig....Ch. 21 - An ideal refrigerator or ideal heat pump is...Ch. 21 - A heat engine is being designed to have a Carnot...Ch. 21 - A power plant operates at a 32.0% efficiency...Ch. 21 - You are working on a summer job at a company that...Ch. 21 - A Carnot heat engine operates between temperatures...Ch. 21 - An electric generating station is designed to have...Ch. 21 - Suppose you build a two-engine device with the...Ch. 21 - A heat pump used for heating shown in Figure...Ch. 21 - A gasoline engine has a compression ratio of 6.00....Ch. 21 - An idealized diesel engine operates in a cycle...Ch. 21 - (a) Prepare a table like Table 21.1 for the...Ch. 21 - Prob. 21PCh. 21 - A Styrofoam cup holding 125 g of hot water at 100C...Ch. 21 - A 1 500-kg car is moving at 20.0 m/s. The driver...Ch. 21 - A 2.00-L container has a center partition that...Ch. 21 - Calculate the change in entropy of 250 g of water...Ch. 21 - What change in entropy occurs when a 27.9-g ice...Ch. 21 - When an aluminum bar is connected between a hot...Ch. 21 - When a metal bar is connected between a hot...Ch. 21 - How fast are you personally making the entropy of...Ch. 21 - Prob. 30APCh. 21 - The energy absorbed by an engine is three times...Ch. 21 - In 1993, the U.S. government instituted a...Ch. 21 - In 1816, Robert Stirling, a Scottish clergyman,...Ch. 21 - Suppose an ideal (Carnot) heat pump could be...Ch. 21 - Review. This problem complements Problem 44 in...Ch. 21 - A firebox is at 750 K, and the ambient temperature...Ch. 21 - A 1.00-mol sample of an ideal monatomic gas is...Ch. 21 - A system consisting of n moles of an ideal gas...Ch. 21 - A heat engine operates between two reservoirs at...Ch. 21 - You are working as an assistant to a physics...Ch. 21 - Prob. 41APCh. 21 - You are working as an expert witness for an...Ch. 21 - An athlete whose mass is 70.0 kg drinks 16.0...Ch. 21 - Prob. 44APCh. 21 - Prob. 45APCh. 21 - A sample consisting of n moles of an ideal gas...Ch. 21 - The compression ratio of an Otto cycle as shown in...
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
- Notation matters when working with vectors! In particular, it is important to distinguish between the vector itself (A) and its magnitude (A). Illustrate in four separate sketches that each of the following statements is possible: a) both R = A + B and R=A+B are correct b) R = A + B is correct, but R=A+B is incorrect c) R = A + B is incorrect, but R=A+B is correct d) both R = A + B and R=A+B are incorrectarrow_forwardYou know from your math courses that an infinitesimal segment of a circular arc can be considered as a straight line segment. Imagine that you cover a full circle in, say, the clockwise direction, with infinitesimal displacement vectors dr. Then evaluate fdr and fdr (the circle symbol on the integral just reminds us that we have to go around the full circle).arrow_forwardWhen 1.00 g of water at 100˚C changes from the liquid to the gas phase at atmospheric pressure, its change in volume is: 1.67 x 10^-3 How much heat is added to vaporize the water? How much work is done by the water against the atmosphere in expansion? What is the change in the internal energy of the water?arrow_forward
- 1 m3 of pure water is heated from 10˚C to 120˚C at a constant pressure of 1 atm. The volume of the water is contained, but allowed to expand as needed remaining at 1 atm. Calculate the change in enthalpy of the water. You are provided with the following information at the conditions of 1 atm: The density of pure water between 10˚C and 100˚C: 1000kh/m^3 The heat capacity of water: 4.18 kj/kgK Enthalpy required to convert liquid water to gas (enthalpy of vaporization): 2260 kj/kg The heat capacity of steam: 1.7kj/kgk Is the reaction endothermic or exothermic? Why?arrow_forwardWhen a dilute gas expands quasi-statically from 0.50 to 4.0 L, it does 250 J of work. Assuming that the gas temperature remains constant at 300 K. What is the change in the internal energy of the gas? How much heat is absorbed by the gas in this process?arrow_forwardA high-speed lifting mechanism supports an 881 kg object with a steel cable that is 22.0 m long and 4.00 cm^2 in cross-sectional area. Young's modulus for steel is 20.0 ⋅10^10 Pa. Determine the elongation of the cable.arrow_forward
- Namor, from Wakanda Forever, sits on a throne at the bottom of the ocean in a city called Talocan (and Atlantis in the comics). Assuming he, including his gold headdress, has a density of 1085 kg/m3 and that Namor is surrounded by salt water with a density of 1027 kg/m3, what is Namor’s normal force while sitting underwater? Take Namor’s mass as 285. kg and solve as if he has a uniform density.arrow_forwardTo get there they need to travel through an area of salt-water, which seems to also be a magical portal, before arriving in a dry area. Judging by the time Maui and Moana spend falling through the water, it seems they dive 3440. ft deep. Assume the portal is non-magical salt-water, with a density of 1027 kg/m^3. Given that the air pressure above the portal is 1.013 ⋅10^5 Pa, what is the pressure when they are 3440. ft deep? 1 m = 3.28 ft. Moana would have a surface area of 1.30 m2. How much force would be acting on her at the bottom of this portal?arrow_forwardA plank 2.00 cm thick and 15.7 cm wide is firmly attached to the railing of a ship by clamps so that the rest of the board extends 2.00 m horizontally over the sea below. A man of mass 92.9 kg is forced to stand on the very end. If the end of the board drops by 5.97 cm because of the man's weight, find the shear modulus of the wood.arrow_forward
- when considering particle B (4,1) distances in relation to P (-4, 5), why are the y coordinates being used gto resolve the distance along the x-axis and vice-versa?arrow_forwardA 198 kg load is hung on a wire of length of 3.58 m, cross-sectional area 2.00⋅ 10-5 m2, and Young's modulus 8.00⋅10^10 Pa. What is its increase in length?arrow_forwardI. Pushing on a File Cabinet Bob has been asked to push a heavy file cabinet down the hall to another office. It's not on rollers, so there is a lot of friction. At time t = 0 seconds, he starts pushing it from rest with increasing force until it starts to move at t = 2 seconds. He pushes the file cabinet down the hall with varying amounts of force. The velocity versus time graph of the cabinet is shown below. A. On the graphs provided below, 1. draw the net force vs. time that would produce this velocity graph; 2. draw the friction force vs. time for this motion; 3. draw the applied force (Fon Cabinet by Bob) VS. time for this motion (the first two seconds of this graph have been drawn for you). Velocity (m/s) Applied Force (N) Friction Force (N) Net Force (N) A -m B -U time (s) D time (s) time (s) time (s)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 LearningCollege PhysicsPhysicsISBN:9781938168000Author:Paul Peter Urone, Roger HinrichsPublisher:OpenStax CollegePhysics for Scientists and Engineers: Foundations...PhysicsISBN:9781133939146Author:Katz, Debora M.Publisher:Cengage Learning
- Physics for Scientists and EngineersPhysicsISBN:9781337553278Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningPhysics for Scientists and Engineers with Modern ...PhysicsISBN:9781337553292Author: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

College Physics
Physics
ISBN:9781938168000
Author:Paul Peter Urone, Roger Hinrichs
Publisher:OpenStax College

Physics for Scientists and Engineers: Foundations...
Physics
ISBN:9781133939146
Author:Katz, Debora M.
Publisher:Cengage Learning


Physics for Scientists and Engineers
Physics
ISBN:9781337553278
Author:Raymond A. Serway, John W. Jewett
Publisher:Cengage Learning

Physics for Scientists and Engineers with Modern ...
Physics
ISBN:9781337553292
Author:Raymond A. Serway, John W. Jewett
Publisher:Cengage Learning
The Second Law of Thermodynamics: Heat Flow, Entropy, and Microstates; Author: Professor Dave Explains;https://www.youtube.com/watch?v=MrwW4w2nAMc;License: Standard YouTube License, CC-BY