Physics 114 – General Physics II
Everyone Pick Up:
•Syllabus
•Student Info sheet – fill it out
Topics Covered:
•30% Electricity
•30% Magnetism
•30% Optics
•10% Modern Physics
Eric Carlson
“Eric”
“Professor Carlson”
Olin 306
Office Hours always
758-4994 (o) 407-6528 (c)
ecarlson@wfu.edu
Materials
•Physics for Scientists and
Engineers, 9th ed., Serway
and Jewett, with webassign,
through chap. 39
•Scientific Calculator*
•iclicker*
•Laptop
•30 cm metric ruler
* - bring these to class
Please Register
your iClicker
http://www.webassign.net/student.html
http://users.wfu.edu/ecarlson/phy114
1/14
Dr. Carlson’s Schedule
9:00
10:00
11:00
12:00
1:00
2:00
3:00
4:00
5:00
Monday
Tuesday
Wednesday
Thursday
Friday
PHY 114
office
hours
PHY 114
office
hours
PHY 114
PHY 742
office
hours
PHY 742
office
hours
PHY 742
research
research
research
research
research
research
research
Free food
colloquium
Preparing for Lecture
Reading Assignment
Quizzes:
•Sections 23.1 – 23.3 by Friday
•Reading quiz 23a by Friday
•Sections 23.4 – 23.6 by Wednesday •Reading quiz 23b by Wednesday
•Read the material assigned on the Web, or in class each day, before class starts
•Take a webassign-based reading quiz online by 9:30 AM
•You only get one chance to answer these questions
http://www.webassign.net/student.html
Class attendance, Seating, Participation
•I do not grade directly on attendance
•But it is basically necessary for class participation
•I will be taking attendance, usually
•Starting Wednesday, everyone will sit in the same seat
every day (your choice which seat)
Do you understand how concept
•Not the back row
iclicker questions work?
Class Participation Grade and the iclicker
A) Yes, I’ve done it before
•I present a multiple choice question
B) Yes, though it’s new to me
•Round 1 – You must figure out or guess the answer, C) Sort of, I’ll figure it out
then vote with your iclicker
D) Huh?
•You discuss the questions with your classmates
•Round 2 – You get a second chance to get the answer right
•Right answers: 4/4, wrong answers: 3/4
•If you get 80% or more, you get full credit on class participation
•Participating in class discussion gains bonus points that can push up your
participation grade, even past full credit
Homework, Webassign
http://www.webassign.net/student.html
•All homework is on webassign
•Bookstore can sell you a license, or you can get it online
•Personalized problems, you need to get correct to 1% or better
•Handout about webassign is on the class web page
•Due almost every class day at 9:30 AM
•Personalized problems – you can’t copy
•Eight chances to get it right
•Getting help is encouraged
•Ask a friend, ask me, come to office hours
•First assignment is due on Wednesday of next week
•Groups will be provided to help you work on homework (or study, or whatever)
Exams
•3 tests and a final
Exam Dates:
•Honors code violations will be turned in to the
February 9
honor council
•Normally, penalty is 1-term suspension and
March 4
an irreplaceable F in the course
April 10
•Multiple choice, short essay and
computational problems
May 6, 9 AM
•If ill, call me/email me immediately or bring a
Doctor’s note
Red dashed line means you
should be able to use this on a
Red boxes mean
test, but you needn’t memorize it
memorize this for the test
Dotted red means easily derived
from other formulas
Other colors mean
not on the test
Miscellaneous
The Web
Numerous materials can be found on
the web for this course
•These lectures
•Math review
•Syllabus and other handouts
•Reading assignments and quizzes
•Test information
http://users.wfu.edu/ecarlson/phy114
Pandemic Plans
•If there is a catastrophic closing of
the university, we will attempt to
continue the class:
Emergency contacts:
Web page
email
Cell: 336-407-6528
Labs
•You are required to sign up for PHY 114L
•You must pass the lab to pass the class
•Labs begin on January 26
Grades
Percentage
Breakdown:
Test 1
12%
Test 2
12%
Test 3
12%
Final
24%
Homework 20%
Lab
10%
Class Part.
5%
Read Quiz
5%
Grade Assigned
94% A
73% C
90% A70% C87% B+
67% D+
83% B
63% D
80% B60% D77% C+
<60% F
•Little if any curving
•Do not allow extra credit
Background Information
Prerequisites
•Physics: PHY 113 (or 111), mechanics, etc.
•You should have a good understanding of basic physics
•Be familiar with units and keeping track of them, scientific notation
•Should know key elementary formulas like F = ma
•Mathematics: MTH 111, introductory calculus
•Know how to perform derivatives of any function
•Understand definite and indefinite integration
•Work with vectors either abstractly or in coordinates
•There is a math review online with everything you need to know
SI Units
Fundamental units
Time
second s
Distance
meter
m
Mass
kilogram kg
Temperature Kelvin K
Charge
Coulomb C
Metric Prefixes
109 G Giga106 M Mega103 k kilo1
10-3 m milli10-6  micro10-9 n nano10-12 p pico10-15 f femto-
Red boxes mean memorize this, not
just here, but always!
Derived units
Force
Newtons N
Energy
Joule
J
Power
Watt
W
Frequency
Hertz
Hz
Elec. Potential Volt
V
Capacitance Farad
F
Current
Ampere A
Resistance
Ohm

Mag. Field
Tesla
T
Magnetic Flux Weber Wb
Inductance
Henry H
kgm/s2
Nm
J/s
s-1
J/C
C/V
C/s
V/A
Ns/C/m
Tm2
Vs/A
Vectors
•A scalar is a quantity that has a magnitude, but no direction
m, t , T , r
•Mass, time, temperature, distance
•In a book, denoted by math italic font
•A vector is a quantity that has both a magnitude and a direction
s, v, a
•Displacement, velocity, acceleration
•In books, usually denoted by bold face
s, v, a
•When written, usually draw an arrow over it
z
•In three dimensions, any vector can be described
in terms of its components
v   vx , v y , vz 
•Denoted by a subscript x, y, z
•The magnitude of a vector is how long it is
v
•Denoted by absolute value symbol, or
same variable in math italic font
v
x
v v  v v v
2
x
2
y
2
z
x
vy
y
vz
Concept Question
v  1ˆi  2ˆj  2kˆ
v v 
2 cm
What is the length of the long diagonal of
a box that is 2 cm 2 cm  1 cm?
A) 1.732 cm B) 3 cm
C) 5 cm
D) 9 cm
E) None of the above
2 cm
1 cm   2 cm    2 cm 
2
2
2
 3 cm
Announcements
Day
Today
Wednesday
Friday
ASSIGNMENTS
Read
Quiz
Sec. 23.1-23.3 Quiz 23a
Sec. 23.4-23.7 Quiz 23b
Sec. 24.1-24.2 Quiz 24a
Homework
none
Hwk. 23a
Hwk. 23b
Tutorial Sessions
Olin 101, 7-9, start Monday
Sunday, Thursday: Jiajie
Monday, Tuesday, Wednesday: Lauren
SPS Meeting
Tuesday, Jan. 21, 12:00
Olin Lobby
Free pizza and soft drinks
Pick Up Class
List in Front
1/16
Lauren Nelson
Jiajie Xiao
Finding Components of Vectors
•If we have a vector in two
dimensions, it is pretty easy to
compute its components from its
magnitude and direction
vx  v cos 
y
v
v y  v sin 
v
vy
•We can go the other way as well
v  vx2  v y2
 vy 
  tan  
 vx 
1
•In three dimensions it is harder
v  vx2  v y2  vz2

vx
x
Unit Vectors
v̂
v
•We can make a unit vector out of any vector
•Denoted by putting a hat over the vector
•It points in the same direction as the original
vector
•The unit vectors in the x-, y- and z-direction are
very useful – they are given their own names
•i-hat, j-hat, and k-hat respectively
•Often convenient to write arbitrary vector in
terms of these
rˆ 
r r

r r
k̂
î
v  vx ˆi  vy ˆj  vz kˆ
ĵ
Adding and Subtracting Vectors
•To graphically add two vectors, just connect them head to tail
•To add them in components, just add each component
•Subtraction can be done the same way
v  w   vx  wx  ˆi   v y  wy  ˆj   vz  wz  kˆ
v  w   vx  wx  ˆi   v y  wy  ˆj   vz  wz  kˆ
v
vw
w
Multiplying Vectors
There are two ways to multiply two vectors
•The dot product produces a scalar quantity
•It has no direction
•It can be pretty easily computed from geometry
•It can be easily computed from components
v  w  vw cos   vx wx  v y wy  vz wz
•The cross product produces a vector quantity
•It is perpendicular to both vectors
v  w  vw sin 
•Requires the right-hand rule
•Its magnitude can be easily computed from geometry
•It is a bit of a pain to compute from components
 ˆi

v  w  det  vx
w
 x
ˆj
vy
wy
vw
w

v
kˆ 

vz    v y wz  vz wy  ˆi   vz wx  vx wz  ˆj   vx wy  v y wx  kˆ
wz 