Physics 218
Vitaly Kocharovsky
Congratulations: You start to study Physics –
the basis of our understanding of the World !!!
Reasons to know basic concepts of Physics:
(a) It makes you self-reliant and stronger in this life
(b) It greatly facilitates your career
(c) To get the master or other degree
…
Course info: Common to all sections webpage physics218.physics.tamu.edu
Prof. Vitaly Kocharovsky: website http://faculty.physics.tamu.edu/vkochar/
office: MPHY 557; tel.: 862-1652; e-mail: vkochar@physics.tamu.edu
Lectures: Monday, Wednesday, Friday
10:20-11:10 (sec. 591-595; MPHY 204) and 13:50-14:40 (sec. 510-514,561; MPHY 205)
Office hours: Monday, Wednesday, Friday 11:10–12:10 & by appointment
(1) Textbooks “University Physics", v. 1 (13th edition by Young and Freedman) with
Modified MasteringPhysics online homework;
(2) smartPhysics – online prelectures and assessments (checkpoints);
(3) WebAssign – online lab manual with write-ups turned in via WebAssign website;
(4) i>Clicker2 quizzes at each lecture.
Course grade is a sum of the following contributions:
Note: Final exam replaces the
lowest midterm, if final is higher.
3 Midterm Exams (10%, 10%, 10%)
30%
Final Exam
30%
Laboratory (you must pass > 70%)
10%
Recitations and Recitation Quizzes
10%
MasteringPhysics Homework (>70%)
10 %
i>Clicker2 Lecture Quizzes
5%
-------------------------------------------------------------------------------------------------------------
---------------
smartPhysics Prelectures&Checkpoints
5%
Lecture Structure
• You will have to routinely watch online
smartPhysics prelectures and read material
of each new Chapter in the textbook
before each lecture!!!
• Clicker Quizzes:
– In-class quiz at the beginning of the lecture using
“clickers” to check reading assignment
– One or two mini-quizzes during and/or at the end
of the lecture
• Lecture iClicker Quizzes and smartPhysics
prelectures contribute 10% to your final score
Online MasteringPhysics Homework
• Weekly assignments on MasteringPhysics website (check often):
– Need to get 70%+ final Homework score to pass the course
– Each late portion of HW gets 10% reduction in score
PER EACH DAY LATE, so if it’s 3 days late and you did not yet start
working on you assignment, you are done with this class
• Important:
– There is an option to “give up” on a problem in MP. Don’t use it!
• If you “give up” on problems, it’s irreversible and it can bring your
score below 70%!
• Instead, move on to another problem and go back to this problem later
(you don’t have to do them in order)
• Important: start working on HW problems early!!!
• Adaptive Follow-Up assignment for each chapter worth a total
of 2 points of extra credit
• Typical semester average student’s score on HW is about 90%
Online MasteringPhysics Homework
• You have to register and access Mastering through eCampus
(It doesn't require a course ID as the link within the course provides students
direct access for single sign on and gradebook integration.)
Also, it is possible to do MasteringPhysics homework directly at
http://www.pearsonmylabandmastering.com, if ecampus does not work.
• The Introduction and Math Review is due Sunday, Sept. 7
• The first homework (Ch. 1) from syllabus is due Sept. 14th,
i.e., Sunday on the week of your recitation session on Ch.1
• Every homework from syllabus is due Sunday on the week
of your recitation session on the corresponding chapter.
How to Pass This Course
• In order to pass this course you must:
– Take all the exams and the final
AND
– Pass the Lab part with >70%
AND
– Get 70+% on MasteringPhysics homework
AND
– Have your total score above the F range
What to Expect: Physics 218
• Be prepared that this is one of very hard
and time consuming classes
– Need typically 10 hours of hard work a week
besides classes
• Inter-relation and intensity of the material
makes it harder:
– You miss one thing, but it will come and bite
you several times as the same concepts
repeat throughout the course
• If you can’t afford that much time, take this
class next semester
Simple schedule
• We will generally follow this sequence:
- Always material first is covered in the lecture and
then, in one or two weeks, it is covered in recitation
- By 11:59 pm on Sunday of the week of recitation
the full HW assignment on that material has to be
completed online at MasteringPhysics
• Start working on your MasteringPhysics HW
early, definitely before recitation
• Work on smartPhysics prelecture&checkpoints
and read material in the textbook before the
lecture and prepare for lecture iClicker quizzes
How To Do Well in Physics 218
• Maximize scores in all “service” categories
– Labs, recitations, HW, clicker quizzes,and smartPhysics prelectures
• Do your best on the exams
– They are what really matters most to your final grade!!!
• You won’t do well on exams unless you train yourself in
solving HW problems
– Do problems yourself: if someone explains you the solution and
you “understood” it, that’s not good enough
– If you are stuck, ask for help with a similar problem; if you had to
get help with a HW problem, solve 5 more similar ones from the
book yourself
– Really helps to go beyond HW assignments and do more problems
from the textbook
– You likely will have to struggle through some of the problems, but
that’s the only way. You will notice that soon things will start
coming to you easier
How It’s Meant to Work
• Your read material of the chapter and watch smartPhysics
prelecture before lecture
– The book is excellent and very useful
• In lecture I walk over the most important concepts,
fix typical misunderstandings and help you learn how to
“think right” and feel the actual logic behind the concepts
– Common sense, physical intuition, lots of visual examples help
– If you didn’t read the material and watch smartPhysics prelecture
ahead of time, it will not be nearly as helpful
• Do homework problems until you can do almost any
problem in the book
– Many will struggle in the beginning, but if you keep pushing you
will start “getting it” and there is no other way really
– Recitations focus on problems, the place where you can get help
with remaining challenges
• But you have to start on the homework well before the recitation
Tutoring
• Not a bad idea, but be careful:
– You do not want a tutor who is solving problems
for you and trains you to solve “standard exam
problems”
– You want someone who will:
•
•
•
•
spend time finding your weak spots
help you understand concepts
teach you how to solve problems
check that you figured this material by letting you
solve several problems on the same subject while
watching your steps and logic
Clicker
• Model called “i>Clicker 2”
• Get them now before the bookstore
ran out of them!
• Register your clicker by logging into
ecampus.tamu.edu with your NEO login
and password or by going directly to
www.iclicker.com (see instructions at the
common for all sections of Physics 218
webpage physics218.physics.tamu.edu)
Clickers Setup
• Turn on your clicker (press the power button)
• Set the frequency:
– Press and hold the power button
– Two letters will be flashing
– If it’s not “AC”, press “A” and then “C”
• If everything works, you should see
“Welcome” and “Ready”
Clicker Question #1
When do you think the first man will arrive on Mars?
A. Before 2020
B. Between 2020 and 2030
C. Between 2030 and 2040
D. Between 2040 and 2050
E. After 2050
We use the “AC” frequency in this class
Physics and Structure of Nature
Mechanics: Isaac Newton (1642–1727)
Kinematics and Dynamics
Velocity
Fields and Particles
Four fundamental forces
in Nature
Mediators: boson fields =
gauge particles
Gravitational
Graviton ?
Electromagnetic
Photon
Weak
W±, Z bosons
Strong
8 gluons
Fundamental elementary particles
(fermions): Three families
Each quark exists in 3 colors (red, green, blue)
Observable particles:
barions (qqq) and mesons ( q q )
6 Quarks
Trajectory
Force
6 Leptons
u (up)
d (down)
e (electron)
νe (neutrino)
s (strange)
c (charm)
μ (muon)
νμ (neutrino)
b (beauty)
t (top)
τ (tau-lepton)
ντ (neutrino)
Proton
Neutron
Electrodynamics
James Clark Maxwell ( 1831 – 1879 )
Interaction of the charged particles via
an electromagnetic field is responsible
for all phenomena in chemistry,
biology, medicine, and ordinary life.
Atoms and molecules
in solids, liquids, gases, and plasmas
Electron
Nucleus
Electromagnetic
field
1fm = 10-15m
Physics as Science:
•Experimental science ≠ Math
•Physical quantities (exactly defined and measurable)
•Elementary constituents of matter, interactions, processes
•Idealizations and models
•Math equations
•Range of validity
Example: Classical non-relativistic mechanics
Physical quantities and units
Derived units Base units
International System (SI)
Gauss’ System (CGS)
“Centimeter-Gram-Second”
Physical quantity
Name of SI unit
SI symbol
Name of CGS unit
CGS symbol
length
meter
m
centimeter
cm
mass
kilogram
kg
gram
g
time
second
s
second
s
frequency
hertz
Hz=1/s
hertz
Hz=1/s
velocity
meter/second
m/s
centimeter/second
cm/s
force
newton
N=kg·m/s2
dyne
dyn=g·cm/s2
energy
joule
J=N·m
erg
erg=dyn·cm
power
…
watt
…
W=J/s
…
erg/s
…
g·cm2/s3
P.S.: Never forget to specify units !!!
Example: crash of a satellite on Mars
3 m + 4 feet = 4.2 m ≠ 7 ?
…
Unit conversions
1. Height H= 2 m = 2 · 3.28 feet = 6.56 feet
1m=3.28 feet
2. Time of light propagation from the Sun to the Earth
8 minutes = 8·60 s = 480 s
1mile =1.6 km = 1600 m
3. Speed of a car v = 36 miles/hour = 36·1600m/3600s=16m/s
1hour=60·60s=3600s
Dimensional analysis
Dimensions of the physical quantities are algebraic combinations of the
fundamental dimensions of length [L], mass [M], and time [ T ].
Example: x=vt ↔ [L] = [ L / T ] · [ T ]
but x ≠ vt2 since [L] ≠ [ L / T ] · [ T ]2 = [ L ] · [ T ]
Scales and units of physical quantities
1 second = 9 192 631 770 cycles of electron in cesium-133 atomic clock
1 second ≈ 1 day / (24·60·60)
1 year ≈ π·107 seconds ≈ 3·107 s
1 meter = c · (1 / 299792458) s ,
where a speed of light in vacuum is c=299792458 m/s ≈ 300 000 km/s.
Size of an atom La~1 Angström = 1Å =10-10m ~ c·10-18s
1 light year = c·1year ≈ 3·108 m/s · 3·107 s ≈ 1016 m
Size of the Universe is 13.7 billion years · c = 13.7·109 ly
1 kilogram= mass of a standard cylinder of platinum-iridium alloy =1000g
Proton mass ≈ neutron mass is mp ~ 10-24 g = 10 -27 kg
Milky Way Galaxy
D ~ 100 000 light years
Sun
Distance to the nearest star
Proxima Centauri is L=4.2 ly
R ~ 30 000 light years
Center of
Galaxy
Time of space travel to Proxima Centauri T = L/v =4.2years·c/v
= 4.2 years · (300 000 km/s / 30 km/s) = 42 000 years
Vector algebra
Scalar is a real number independent on coordinate system:
mass, volume, distance, pressure, temperature, …
Vector (arrow with magnitude and direction)
3



A   A i is a set of components which transform
 1
3
3



 

as A   C  A  with a basis rotation i    C  i
 1
Tail-to
-head
 1
Resolving a vector into its components:





A  Ax  A y  Ax i x  A y i y

iy

ix
 
i x , i y a re u n i t v e c t o rs
Pythagorean theorem → Magnitude:
Direction: cos  
Ax
A
, sin  
Ay
A
,
tan  
A
Ay
Ax
Ax  Ay
2
2
A x  A cos
Scalar (dot) product is a number
 
A  B  A B cos  A x B x  A y B y  Az B z

B


A
Vector (cross) product is a vector

 
A  B  ( A y B z  Az B y )i x  ( Az B x  A x B z )i y  ( A x B y  A y B x )iz 
  
i x i y iz
Right-hand rule
 A x A y Az
Bx B y Bz
 
A  B  AB sin 
 
 
B A  A B