engr 102 · ch 15. energy (lectures 10-16) • vocabulary and concepts see vocabulary list ideas...
TRANSCRIPT
ENGR 102PROBLEM SOLVING FOR ENGINEERS
Lec
ture
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5
May 5, 2020
I N T O / C S U P A R T N E R S H I P
REVIEW FOR EXAM 4
VOCABULARY, ENERGY, AND THERMODYNAMICS
www.youtube.com/watch?v=MGHZ0Ww1Rfs
Source of images: Amazon.com
10,000 HOUR RULE
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Source: zintro.com
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NEXT WEEK(All times are in Colorado. Qatar/Kuwait +9 hours. Korea +15 hours)
Sunday Monday Tuesday Wednesday Thursday Friday
May 5Assignment
23 noonVideo class
3:30 pm
May 6 May 7Assignment
24 noonVideo class
3:30 pm
May 8
May 10Recitation 3:30 pm
May 11Exam 4
9:40 -11:40am
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Exam 4 – Monday, May 11
Ch 16. Thermo(Lectures 10-16)
Ch 15. Energy(Lectures 10-16)
• Vocabulary and concepts See vocabulary list Ideas related to vocabulary list
• Gas law question See Assignment 24, Question 3
• Energy conversion calculation See assignment 23, Question 3
• Thermodynamics Use 7-step process See Assignment 23, Question 4 See Assignment 24, Questions 4 & 5
Ch 7. Units and
dimensions(Lecture 9)
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ASSIGNMENT 23 & NOTES
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ASSIGNMENT 24 & NOTES
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ASSIGNMENT 23(Due before noon on Tuesday, May 5)
1. Number of students in this class = __6__
2. Students with homework on time = __6__
3. Number of students with full credit = __6__
4. Students with all questions correct = __0__
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Exam 4 – Monday, May 11
Ch 16. Thermo(Lectures 10-16)
Ch 15. Energy(Lectures 10-16)
• Vocabulary and concepts See vocabulary list Ideas related to vocabulary list
• Gas law question See Assignment 24, Question 3
• Energy conversion calculation See assignment 23, Question 3
• Thermodynamics Use 7-step process See Assignment 23, Question 4 See Assignment 24, Questions 4 & 5
Ch 7. Units and
dimensions(Lecture 9)
1010
Vocabulary on Exam 4
Words will be in questions to test your understanding, such as:
Explain when to use Carnot efficiency and when to use refrigeration efficiency when making a thermodynamicscalculation.
Give an example of a closed system that converts mechanical work to electricity.
Give an example of a process in which entropy is not produced.
When would you need to calculate using moles in this class?
Write the equation for the first law of thermodynamics.
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Vocabulary on Exam 4(Example of logical groupings)
Units and dimensions: Basic energy terms:
Energy, society & environment:
Forms of stored energy:
Gas law problems:
Energy conversion devices:
Solving energy equations:
Can be written as equations:
Base unitDerived unitDimensionUnit
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Units and dimensions:Base unitDerived unitDimensionUnit
Gas law problems:MoleAbsolute temperature
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Units and dimensions:Base unitDerived unitDimensionUnit
Gas law problems:MoleAbsolute temperature
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Vocabulary on Exam 4(Example of logical groupings)
Units and dimensions: Basic energy terms:
Energy, society & environment:
Forms of stored energy:
Gas law problems:
Energy conversion devices:
Solving energy equations:
Can be written as equations:
Base unitDerived unitDimensionUnit
MoleAbsolute temperature
Alternative energyConsumptionFossil fuelGreenhouse gasHuman development indexLife expectancyRenewable energyStandard of living
1515
Energy, society & environment:Alternative energyConsumptionFossil fuelGreenhouse gas
Human development indexLife expectancyRenewable energyStandard of living
1616
Vocabulary on Exam 4(Example of logical groupings)
Units and dimensions: Basic energy terms:
Energy, society & environment:
Forms of stored energy:
Gas law problems:
Energy conversion devices:
Solving energy equations:
Can be written as equations:
Base unitDerived unitDimensionUnit
EnergyEntropyMechanical workPowerThermodynamics
MoleAbsolute temperature
Alternative energyConsumptionFossil fuelGreenhouse gasHuman development indexLife expectancyRenewable energyStandard of living
17
Basic energy terminology: EnergyEntropyMechanical workPowerThermodynamics
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Vocabulary on Exam 4(Example of logical groupings)
Units and dimensions: Basic energy terms:
Energy, society & environment:
Forms of stored energy:
Gas law problems:
Energy conversion devices:
Solving energy equations:
Can be written as equations:
Base unitDerived unitDimensionUnit
EnergyEntropyMechanical workPowerThermodynamics
MoleAbsolute temperature
Chemical energyInternal energy / HeatKinetic energyNuclear energyPotential energy
Alternative energyConsumptionFossil fuelGreenhouse gasHuman development indexLife expectancyRenewable energyStandard of living
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Forms of stored energy: Chemical energyInternal energy / HeatKinetic energyNuclear energyPotential energy
Chapter 16Assignment 9Lecture 10
2020
Vocabulary on Exam 4(Example of logical groupings)
Units and dimensions: Basic energy terms:
Energy, society & environment:
Forms of stored energy:
Gas law problems:
Energy conversion devices:
Solving energy equations:
Can be written as equations:Conservation of energyCarnot efficiencyEfficiencyFirst law of thermodynamicsGas lawRefrigeration efficiencySecond law of thermodynamics
Base unitDerived unitDimensionUnit
EnergyEntropyMechanical workPowerThermodynamics
MoleAbsolute temperature
Chemical energyInternal energy / HeatKinetic energyNuclear energyPotential energy
Alternative energyConsumptionFossil fuelGreenhouse gasHuman development indexLife expectancyRenewable energyStandard of living
Combustion engineElectric generatorElectric motorFrictionHeat pump
Absolute temperatureAccumulateClosed systemOpen system
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Can be written as equations:Conservation of energyCarnot efficiencyEfficiencyFirst law of thermodynamicsGas lawRefrigeration efficiencySecond law of thermodynamics
Energy conversion devices:Combustion engineElectric generatorElectric motorFrictionHeat pump
Solving energy equations:Absolute temperatureAccumulateClosed systemOpen system
Chapter 16Assignment 10
Lecture 11
Chapter 16Assignments 11, 12 & 14Lectures 12-14 and 16
Videos in Assignment 23
Example:
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Gas law: pv=nrt
First law of thermodynamics:Conservation of energy:
Σ(energy inputs) = Σ(energy outputs)
Efficiency = (useful output)/(total inputs)
Second law of thermodynamics: EntropyT2 >= EntropyT1
Carnot efficiency = 1 - TL/TH
Refrigeration efficiency = 1/(TH/TL -1)
CAN BE WRITTEN AS EQUATIONS
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Vocabulary on Exam 4
Words will be in questions to test your understanding, such as:
Why is absolute temperature important for thermodynamics?
Can potential energy in the world ever increase? Explain why or why not?
What base units are needed to define a kilowatt?
Explain whether the world is an open system or a closed system based on how those terms were defined in this class.
Friction converts _________________ to _________________.
What can you do to increase the Human Development Index?
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ASSIGNMENT 23, Question 2a
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ASSIGNMENT 23, Question 2b
Life expectancy+ Education+ Standard of living= Human development index
Having higher life expectancy doesn’t require consuming more energy.
Greater education doesn’t require consuming more energy.
In many cases, it can be possible to have a higher standard of living without consuming more energy because a lot of energy is wasted.
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ASSIGNMENT 23, Question 2c
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ASSIGNMENT 23, Question 2d
By the coronavirus epidemic, people are trying to stay in the home. As a result, they don't use their own cars and other transportation like bus, metro, and airplanes. So, greenhouse gas emission are getting less than normal condition.
Factories in china has shut down, there are less planes, less cars etc., all of these have a positive impact among the environment.
Because of coronavirus epidemic, people are trying not to go out as a result, they don’t use their cars and also other transportations, so greenhouse gas emissions are less than normal.
The covid-19 decreased the pollution because most of the workers stayed at home and most of the factories and industries for the countries reduced or stopped working. Which affected positively on the greenhouse gas emissions.
I think the coronavirus reduce greenhouse gas because it reduces the frequency of people go outside and using car.
Definitely we can say the air pollution. Because of the coronavirus epidemic, people are being quarantine and a lot of cars are not going on the road so the air pollution are decreasing and could be good effects to everything including greenhouse gas emissions.
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What is meant by “greenhouse gas?”
1. What is a greenhouse?
2. What does a greenhouse gas do?
3. Which are the most important greenhouse gases?
_____ Carbon dioxide
_____ Water vapor
_____ Nitrogen
_____ Carbon
_____ Methane
1
2
3
Not a gas
N2 not problem. N2O is greenhouse gas
CSU is #1 in the USA for atmospheric science
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kinetic energy = (0.5)(mass)(velocity)2
mass = (2)(kinetic energy)/(velocity)2
mass = (2)(625,000 kg m2/sec2)/((95,000/3,600)m/sec)2
mass = (1,250,000 kg m2/sec2)/((950/36)m/sec)2
mass = (12,500 kg)/(95/36)2
mass = 1795 kg
mass = 1800 kg (2 significant digits)
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Diesel
engine5.4 liters
@38 MJ/liter
Work
(42%)
Qheat1
(58%)
Qin Electric
generator
Qheat2
(25%)
Electricity
(75%)
Building
Electricity = (75%)(42%)(5.4 liters)(38 MJ/liter) = 64 MJ
Heat = [(58%)+(42%)(25%)](5.4 liters)(38 MJ/liter) = 141 MJ
Note: you didn’t need the answer, only the equations.
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7-STEP PROCESS
General process (Chapter 4.4):Problems other than material balance
1. Problem statementWhat to calculate?
2. DiagramInclude all variables and values
3. TheoryAll equations
4. AssumptionsInformation to simplify calculation
5. Calculation stepsDetail so others can follow and to ensure that there are no errors
6. ResultsRight units and significant digits
7. Discussions/conclusionWhat did we learn?How can we use this?What are next steps?
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NEXT WEEK(All times are in Colorado. Qatar/Kuwait +9 hours. Korea +15 hours)
Sunday Monday Tuesday Wednesday Thursday Friday
May 5Assignment
23 noonVideo class
3:30 pm
May 6 May 7Assignment
24 noonVideo class
3:30 pm
May 8
May 10Recitation 3:30 pm
May 11Exam 4
9:40 -11:40am
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