Download - Introduction Basic Physics
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Lecture Objectives
Understand the procedural requirements of this course.
Understand where this body of knowledgefits in the skill set needed for and engineer Have a general sense of the role materials
have played in technological developmentand their role as limiting technologies.
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Course Objectives
Key concepts to help you organize this areaof knowledge
Tools to help in material selection for design.Learn language and concepts so you can
deal with Materials ProfessionalsDevelop general skills necessary for professional success.
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Grade Components
Course grade 75% Lecture/ 25% Lab
Lecture Grade – 30% Midterms – 30% Final Exam
– 20% Homework – 20% Quizzes
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Keys to Success
Do the HomeworkDon’t miss class & don’t be late
Turn in everything required in labLearn from the lecture objectivesMake sure you can do the kinds of problems
specified.DON’T MEMORIZE – UNDERSTAND!
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Special Engineering Skills
Tools of ApproximationThe sanity Check – the
“Engineering Sense” Units, Units, UnitsPrecision and Accuracy
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Classes of Materials
A. Metals
B. Ceramics
C. Polymers
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Fourth Class of MaterialsComposites
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Materials History: Stone Age
Earliest materials: – stone (ceramic) – wood (natural
composite)
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Materials History: Bronze Age
Copper Alloy (Cu andSn), Adobe (ceramiccomposite)
Bronze agecivilizations in Europe,
Asia, and the Americas
Greece (bronze)conquered by Rome(Iron)
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Materials History: Iron Age
Iron harder & stronger than bronzeIron civilizationsgenerally conqueredbronze based cultures
British Iron Age sword &shield (200-300 BC)
Thebritishmuseum.ac.uk
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Materials History: Age of Steel
From around 1800 tomid 1900’s Steel is a controlledalloy of iron andcarbon
Eades Bridge – StLouis, Missouri
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Mid 1900’s to 1980’s: Age of Engineering Materials
Large variety of materials available – polymers, metal alloys, composites,ceramicsNo single material dominantDetailed characterizations available for precise and reliable use
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1980-? The Age of EngineeredMaterials
Rapid expansion of biological materials,tissue engineering, advanced composites,toughened ceramics, superalloysMaterials designed to requirements of theproduct engineer Concurrent engineering required
THE MATERIAL AND THE PRODUCT AREDESIGNED TOGETHER
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The Place of Materials inManufacturing Engineering
Material
PeopleProcess
Product
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The Place of Materials inMechanical Engineering
CONCEPT
ANALYSIS
MATERIALS
PRODUCT
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Terms & Concepts: Force
“Push or pull of one object on another.”
Five forces in the universe-Electric-Magnetic
-Strong-Weak -Gravitational
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Application
What force is holding you up against the pull
of gravity as you sit in your seat?
a. Normal force c. Strong force
b. Magnetic force d. Electrical force
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Terms & Concepts: Temperature
Temperature is a measure of the averagespeed of molecules in a piece of matter.
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The speed of particles is distributed accordingto a Maxwell distribution
Temperature
Fraction
Of
Atoms
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The root mean squared (rms) velocity can beestimated from:
VRMS = 3kT/m
where k – Boltzman’s constant,T- temperature in K, m – mass of particles
Temperature
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Temperature
Absolute scale: Kelvin At 0K there is no Kinetic Energy
K = C + 273
HINT: If you always use K in the class, you
will never be wrong due to a temperatureinput.
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Application Question
CO 2 leaves a closed plastic soda bottlethrough a process called diffusion. Themolecules squeeze between the polymer molecules. If the temperature of a storagewarehouse is increased will the soda lose itfizz?a. Faster b. Slower c. No change
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Terms & Concepts: Pressure
Caused by the collision of molecules
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Crude estimate of number of collisions per unit area (flux)
= nvwhere n-number of molecules per unitvolume, v-most probable velocity fromdistribution
Pressure
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Application QuestionFormation of polyethylenepolymer requires that
molecules in a gascollide with each other and react (combine) tomake long chains.Higher temperatures willresult in more collisionswhich increase the
production rate.
A. True B. False https://reader009.{domain}/reader009/html5/0428/5ae45bff533a0/5ae45c0d136
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Pressure in Solids
In a solid – pressure is called stress.Stress is the amount of force per unit area
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First Universal Principle
“All systems seek the lowest possible freeenergy state ”
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First Universal Principle
“All systems seek the lowest possible freeenergy state ”
-Water flows downhill – reduces PE
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First Universal Principle
“All systems seek the lowest possible freeenergy state ”
-Water flows downhill – reduces PE-Electrons drop to lowest energy level
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First Universal Principle
“All systems seek the lowest possible freeenergy state ”
-Water flows downhill – reduces PE-Electrons drop to lowest energy level-Water forms spherical droplets – surfaceenergy minimization
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First Universal Principle
“All systems seek the lowest possible freeenergy state ”
-Water flows downhill – reduces PE-Electrons drop to lowest energy level-Water forms spherical droplets – surfaceenergy minimization
-Hot things “cool off” by giving away KE
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First Universal Principle
“All systems seek the lowest possible freeenergy state ”
-Water flows downhill – reduces PE-Electrons drop to lowest energy level-Water forms spherical droplets – surfaceenergy minimization
-Hot things “cool off” by giving away KE -The entire universe is winding down
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Comprehension Self-Test
1. Temperature is the measure of the average ______ of molecules in a piece of matter.
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Comprehension Self-Test
1. Temperature is the measure of the average speed of molecules in a piece of matter.
2. The five forces in the universe are electric,magnetic, strong, weak, and ______.
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Comprehension Self-Test
1. Temperature is the measure of the average ______of molecules in a piece of matter.a. number b. size c. speed d. charge
2. The force by which the chair is holding you up isa. magnetic b. gravitational c. strong d. electric
3. In the measurement of V RMS , velocity increases asthe square root of the _____.
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Comprehension Self-Test
1. Temperature is the measure of the average speed of molecules in a piece of matter.
2. The five forces in the universe are electric,magnetic, strong, weak, and gravitational.
3. In the measurement of V RMS , velocity increases asthe square root of temperature.