college physics lecture outline

8/9/2019 College Physics Lecture Outline

1/18

Chapter 0I Lecture

2014 Pearson Education, Inc.

Introducing

Physics

Prepared by

Dedra Demaree,

Georeto!n "ni#ersity


2/18

$hy do !e need to use mode%s to e&p%ain the!or%d around us'

(o! is the !ord )%a!) used

di**erent%y in physics than inthe %ea% system'

(o! do !e so%#e physicsprob%ems'



3/18

The processes involved in doing physics

include:

Co%%ectin and ana%y+in e&perimenta% data.

a-in e&p%anations and e&perimenta%%y testinthem.

Creatin di**erent representations e.., pictures,raphs, bar charts/ o* physica% processes.

indin mathematica% re%ations bet!een di**erent#ariab%es.

estin those re%ations in ne! e&periments. 2014 Pearson Education, Inc.


4/18

Definitions:

La! a mathematica% re%ation bet!een #ariab%esin*erred *rom the data or throuh somereasonin process

(ypothesis an e&p%anation usua%%y based on

some mechanism under%yin !hat is oin on Prediction a c%ear e&pectation about the

outcome o* an e&periment based on thehypothesis bein tested

ode% a simp%i*ied representation o* a physica%phenomenon

3ssumption a purpose*u% simp%i*ication made to

a physica% situation !hen a mode% is app%ied 2014 Pearson Education, Inc.


5/18

Science is a cyclical process for creating

and testing knowledge.



6/18

A model is a simplified representation of an

obect! a system "a group of obects#! an

interaction! or a process.

3 scientist creatin the mode% decides !hich

*eatures to inc%ude and !hich to ne%ect.

Ga%i%eo Ga%i%ei is be%ie#ed to be the *irst scientist

to conscious%y mode% a phenomenon.

(e chose to simp%i*y the rea% phenomenon by

inorin the interactions o* *a%%in obects !ith

the air !hen studyin them in the ear%y 15thcentury.



7/18

Point$like %bects:

Consider sca%e and those aspects o* the motionthat are most critica% to ana%y+e.

3n airp%ane can be mode%ed as point6%i-e !hen%andin.

It is not mode%ed !e%% as point6%i-e !hen par-in.



8/18

Definitions

Physica% 7uantities *eatures or characteristics o*phenomena that can be measured

e&perimenta%%y

"nit a chosen standard o* measure

8I 8ystem a !ide%y accepted and used unitsystem datin bac- to the 1590s

8ini*icant diits the number o* diits that

represent the precision to !hich !e -no! the

#a%ue o* a physica% 7uantity



9/18

&asic SI physical 'uantities and their units



10/18

Scientific (otation

8cienti*ic notation te%%s us the #a%ue o* a number

in a particu%ar unit and the sini*icant diits.

:;00


11/18

)aking estimations:

a-in rouh estimations is use*u%

$hen dea%in !ith situations that ha#e many

#ariab%es.

$hen somethin is impractica% to measure.

$hen you need to -no! rouh%y !hat theoutcome o* a measurement shou%d be to

co%%ect data or chec- a resu%t.

irst se%ect the basic physica% 7uantities !hose#a%ues can be estimated? then combine the

numbers %eadin to the desired ans!er.



12/18

*stimate the number of pounds of food that

an average person eats during a lifetime. 3ssume the a#erae person consumes about 2000 ca%ories@day.

3ssume each ram o* *ood i#es on a#erae ; ca%ories.

2000 ca%ories@day at ; ca%ories@ram < 400 @day

3ssume that the a#erae %i*e e&pectancy is 50 years.

400 @day/=:; days@year/50 years/ < 10,0A0,000 @%i*etime

2.2 %b is 1000 10,0A0,000 @%i*etime < 22,15: %b@%i*etime Is *i#e sini*icant diits appropriate'

he ca%ories@day 7uantity is probab%y uncertain by about ;00

ca%ories.

he ratio 11 @; ca%ories cou%d be 11 @: ca%ories, about 0.0=

di**erent *rom our estimate. Li*e e&pectancy o* 50 years cou%d be o** by 10 years.

he %east certain 7uantity has one significant digit, so

20,000 %b@%i*etime



13/18


14/18

,epresenting +ector -uantities

Bector 7uantities are represented by ita%ic

symbo%s !ith an arro! on top , , etc./.

In other te&ts, #ectors may be represented in

bo%d *ont, in brac-ets , as coordinates , /, asa co%umn or ro! F, or usin unit #ector notation.



15/18

ow to /se This &ook

ead the boo- as soon as possib%e !hi%e the

materia% is sti%% *resh in your mind.

irst, scan the re%e#ant sections and, i*

necessary, the !ho%e chapter. (o! do the

ne! ideas *it into !hat you ha#e a%ready%earned'

hen, read the re%e#ant ne! sections/ s%o!%y.

Heep re%atin !hat you read to your current

understandin.

Pay attention to the ipsthey !i%% he%p

pre#ent con*usion and *uture di**icu%ties.



16/18

Interrogation while ,eading

Continuous%y as- yourse%*, WHY IS THIS TRUE?

a-e as-in this 7uestion a habitJ

Ky stoppin and interroatin yourse%* as o*ten

as possib%e about !hat is !ritten in the boo-,

you !i%% be ab%e to understand and rememberthe in*ormation better.



17/18

Problem$Solving Steps 0 and 1

1. 8-etch and rans%ate Imaine !hat is

happenin and reread the materia% to ma-e

sure you understand the situation. rans%ate

in*ormation i#en in !ords into symbo%s and

%abe% your s-etch.2. 8imp%i*y and Diaram Decide ho! to mode% the

situation and !hich interactions must be

inc%uded and !hich can be inored. Dra! a

diaram inc%udin physica% 7uantities? thisdiaram shou%d be a bride bet!een the !ords

in the prob%em and the re%e#ant mathematica%

e7uations.



18/18

Problem$Solving Steps 2 and 3

1. epresent athematica%%y Construct a

mathematica% description o* the situation usin

your s-etch and diaram.

2. 8o%#e and E#a%uate 8o%#e the e7uations and

e#a%uate the resu%ts to see i* they ma-e sense.

2014 Pearson Education Inc

college physics lecture outline

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