Slide 1.1 7/15/2015 12:15:18 PM © Foster U:\Class_Presentations\1_Class.PPT Class 1 - Introduction Part 1 - Contact Before Work10 min Part 2 - Review the

$Page 1: Slide 1.1 7/15/2015 12:15:18 PM © Foster U:\Class_Presentations\1_Class.PPT Class 1 - Introduction Part 1 - Contact Before Work10 min Part 2 - Review the$
Slide 1.1

04/19/23 01:01 AM © Foster U:\Class_Presentations\1_Class.PPT

Class 1 - Introduction• Part 1 - Contact Before Work 10 min• Part 2 - Review the Web Page 15 min• Part 3 - Course Packet Review 10 min• Part 4 - Review the 10 min

‘Learning Objectives’ • Break 10 min• Part 4 - Review the ‘Framework’ 25 min• Part 5 - Review Newton’s Laws 15 min• Part 6 - Closure 5 min

Slide 1.2


Contact Before Work

• In class, you will work insub-teams of two persons;1 sub-team per computer.

• Introduce yourself to the person sharing a computer with you today.

• Briefly discuss what you expect to learn from this class.

Slide 1.3


Begin With the End in Mind :Class Learning Objectives

• Achieve Awareness DoI for the Learning Objectives for this class.

• Demonstrate Knowledge LoL for the 13 Extensive Properties that are

‘conserved’ or can be ‘accounted for’.

• Demonstrate Knowledge LoL for Newton’s first three laws.

Slide 1.4


Break

Be back with your team, ready to work, in 10 minutes :

remember our ECE 340 Class Code of Cooperation !

Slide 1.5


The Framework

SURROUNDINGS( ‘OUTSIDE’ )

SYSTEM BOUNDARY

ACCUMULATED or GENERATED / CONSUMED

( ‘INSIDE‘ )

OUTPUTINPUT

x

y

z

Slide 1.6


The Framework (Continued)

• A general conservation or accounting statement.

• How what’s ‘inside’ can change. ( A general view )

• What extensive properties do we ‘count’?

• How can the amount of each of these properties contained ‘inside’ the system

change?

• What events occurring ‘outside’ ( in the surroundings ) caused the change

‘inside’ the system?

Slide 1.7


Verbal Accounting StatementCAUSE ( IN SURROUNDINGS and SYSTEM ) = EFFECT ( ON SYSTEM )

E.P. = EXTENSIVE PROPERTY ( e.g., TOTAL MASS )

{ Amount ofE.P. entering systemduring time period } { Amount of

E.P. leaving systemduring time period }- +

{Amount of E.P.

contained withinsystem at the endof the time period } {

Amount of E.P.contained within

system at the beginningof the time period }{

Accumulation ofE.P. within

system during time period }= -

Where the accumulation is defined as:

Amount ofE.P. generatedwithin system

during time period{

Amount ofE.P. consumedwithin system

during time period } {Amount of

Accumulation ofE.P. within systemduring time period }- ={ }

Four Equivalent Statements Defining Conservation

• A Property is Conserved if the amount of that Property contained in the System plus the amount contained in the Surroundings is always Constant.

• A Property is Conserved if Generation and Consumption within the System are always Zero.

• A Property is Conserved if the amount of that Property in the Universe is always Constant.

• A Property is Conserved if, in an isolated system, the Amount of that Property is always Constant.

An isolated System is one in which nothing crosses the System Boundary. This last version is the form usually stated (although not this explicitly) in physics texts.

N.B.: Nothing in these statements implies that the amount of a conserved property contained in the system is always constant. The amount may change due to exchange with the surroundings. The amount may not change, however, by generation or consumption.

Slide 1.9


Means of Changing the Amount of an ExtensiveProperty Contained within the System

Extensive Properties Modes for System Exchange 1. Mass 2. Elemental Mass 3. Reactive Species 4. Net Charge 5. + Charge 6. - Charge 7. Linear Momentum 8. Angular Momentum 9. Total Energy10. Mechanical Energy11. Electrical Energy12. Thermal Energy13. Entropy

Possible Modes for Exchange Between the System and the Surroundings

I / O = Input / Output

G / C = Generated / Consumed

Mechanical Energy includes the energy associated with ‘Shaft’ Work, Kinetic and Potential Energy, as well as “ Pressure, ‘Pv’ or ‘Flow’ Work “.

Thermal Energy includes the energy associated with molecular collisions, both random collisions between the molecules of two or more bodies and collisions associated with Dynamic as well as Fluid Friction.

Slide 1.10


Class 1 - ‘Report Out’ (15 min)

When your name is called:– Stand and read your response

to the question.

– State any assumptions that you made.

– Summarize any questionsthat you may have.

Slide 1.11


Means of Changing the Amount of an Extensive Property Contained within the System

I / O = Input / Output ; G / C = Generated / Consumed

Extensive Properties Modes for System Exchange

1. Total Mass 1. I / O ( mass ) 2. Elemental Mass 2. I / O ( mass ) 3. Reactive Species 3. I / O ( mass ) , G / C 4. Net Charge 4. I / O ( charge & current > mass! ) 5. + Charge 5. I / O , G / C ( charge & current ) 6. - Charge 6. I / O , G / C ( charge & current ) 7. Linear Momentum 7. I / O ( mass & forces ) 8. Angular Momentum 8. I / O ( mass & torque ) 9. Total Energy 9. I / O ( mass , heat , & work )10. Mechanical Energy 10. I / O , G / C ( see list ) 11. Electrical Energy 11. I / O , G / C ( charge & current )12. Thermal Energy 12. I / O , G / C ( see list )13. Entropy 13. I / O , G ( irreversible processes)

Slide 1.12


Forces and Newton’s LawsForce : A force must somehow be connected with

the interaction between two things.Newton's First Law :

• (Dynamics) It takes a net unbalance of of force to produce acceleration of the object on which the forces act; (‘Statics’) if the forces are balanced (i.e., if the vector sum is zero), the object will not accelerate.

• Every body sill remain in a state of uniform motion unless acted on by external forces.

Newton’s Second Law ( ... Dynamics … no motion or constant motion NOT !!!! acceleration!!)

• F = d( m v )/dt = m a if the mass is constant.

Newton's Third Law ( ... 'Statics' ... no motion OR constant motion !!!! )• If one object exerts a force on another object, then the second object

exerts an equal but opposite force on the first.

Slide 1.13


A Display the essential features of the problem in a (xx min)labeled sketch. Include an appropriate coordinate system.

B Identify an appropriate system ( or systems ). ( x min)

C What extensive properties are to be accounted for ( x min)or conserved?

D What is an appropriate time period for this problem? ( x min)

E State the applicable balances for the extensive properties (xx min)in tabular form.

F Delineate the specifications, data, and defining relationships. (xx min)

G Analyze the model ( i.e., count variables, equations, etc. (xx min)to determine if the problem can be solved )

H Make appropriate assumptions and quantify the behavior. ( ? min)

Structure for ‘Doing the Work’

Homework Format

Slide 1.14


The Equations

td

systemEd

Qtotal

Woutin

zavgv

uflow

mKE

g2

2

td

systemmd

outinflow

m

22

122

12

2iLVC

system

zGv

usystem

msystem

E

g

td

systemGv

systemmd

externalF

outin

avgv

flowm

M

,2

Slide 1.15


The Equations

td

systemSd

gensystemS

boundary boundaryT

Q

outins

flowm

,

0,,

tduniverseSd

gengssurroundinS

gensystemS

0,

0,

gengssurroundin

Sandgensystem

S allall

Slide 1.16


Model Analysis1. Model Variables

From the Sketch …

From Equation 1 ...

From Equation 2, etc. ….2. Analysis

Variables - Equations_______

Remaining Unknowns - Data - Specifications

- Parameters - Initial Conditions

- Independent Variables _______

Design Variables; Solvable ?

Documents

Slide 1.1 7/15/2015 12:15:18 PM © Foster U:\Class_Presentations\1_Class.PPT Class 1 - Introduction Part 1 - Contact Before Work10 min Part 2 - Review the