Physics 218 Sections 807-809
Instructor: Dr. Alexey Belyanin
Homepage http://faculty.physics.tamu.edu/belyanin/P218/
Office: Engineering/Physics Office Tower (ENPO), Room 509
Phone 845-7785, email belyanin@tamu.edu
Office hours:
Tuesday, Thursday 10-12 am or by appointment
Textbook: “Don’t Panic: Volume I”, by
William H. Bassichis, 5th Edition
Crested Butte, 2007
Grade Policy
Exams 45%
Lab 5%
Quizzes (including homework quizzes) 10%
Final 40%
Grade Policy (cont)
•You must pass both the lecture
(3 midterm exams, final exam, quizzes)
and laboratory (>70%) parts of the course
separately in order to pass the course
Grade Policy (cont)
•If your grade on the Final Exam is higher
than your lowest grade on one of the three
exams during the semester, the grade on the
Final will replace that one lowest exam grade
in computing the course grade (it will only
replace one grade in case of two exams having
the same lowest grade).
•The Final Exam grade cannot be used to
replace an exam that has been missed without
an University excused absence. The missed
exam will count as a zero when computing
your final grade.
All Exams are
• Closed book, no calculators or notes
•No numbers! In general the problems will be
formula solutions with variables
• Problems will be similar to those on
homework and recitation
Similar does not mean identical!
Many of you are used to being given formulas and
numbers to plug into them…
We are not going to do this on the exams!
We’ll use variables…
If you do the homework the way we ask you to,
you’ll be well prepared for the exams!
Homework
You will have weekly homework assignments
Every Tuesday you will have a hw quiz at the
beginning of the class with one problem from
your assignment.
Good news: you are allowed to use YOUR notes
(no books or photocopies)
We will use clickers for hw quizzes, pop quizzes,
and class discussion. You need to buy clickers
and register them at elearning.tamu.edu for this
class
• Buy clickers at MSC bookstore
• Price is around $25; you will use for other
classes. Cost of registration is around $10
• Do not follow the registration procedure
that you receive at the bookstore
• Do not register clickers at einstruction.com
• Register clickers at
http://elearning.tamu.edu/
• You need only your clicker number which
shows up when you turn on the power
Check my webpage for hw assignments
Example for Week 1 (Week Aug 31):
Week Aug 31 (due Sep 8): All Chapter 1
problems and exercises
“Due” means that I’ll give you a hw quiz on
that day
However, please try to solve homework
problems even earlier: before your recitations
on Monday
• Be proactive! Get into it and have fun
• Be serious about an old rule of thumb: you have to
study 2-3 hours a week outside the class per each
credit hour
• Don’t miss classes (lectures, recitations, labs)
• Solve all problems and exercises after each Chapter
in the book
• Don’t fall into the “I understand the concepts but I
can’t do the problems” trap. It means you haven’t
done enough of the problems in the chapters.
• Every year we have students who think they
understand but fail during the exams. Don’t let this
happen to you!
Why study physics?
• the most fundamental of the sciences
provides the basis of our understanding of
the Universe;
We do want to find out how things work!
Provides the basis for all engineering
disciplines
• scientists of all disciplines make use of the
ideas of physics
• fun to learn and adventure!
New golden age of physics
Puzzles of our Universe:
acceleration, dark matter, dark energy
Wonders of nanotechnology:
man-made materials with properties on demand
Energy challenge
Climate challenge
“The Bottom Billion” challenge
What happens when physics is ignored?
The
Royal
Warship
Vasa
capsized on her maiden voyage in
August 1628 after sailing less
than one mile. Raised in 1961 the
Vasa is the only well preserved
17th century warship in the
world. She has her own museum
in Stockholm, Sweden.
Vasa was built top-heavy with
insufficient ballast. It became
clear when she was still in the
port; however, nobody had the
courage to say this to the king.
NASA PRESS RELEASE 09/30/1999
Douglas Isbell Headquarters, Washington, DC Sept. 30, 1999 (Phone: 202/358-1753)
Mary Hardin Jet Propulsion Laboratory, Pasadena, CA (Phone: 818/354-5011) Joan
Underwood Lockheed Martin Astronautics, Denver, CO (Phone: 303/971-7398)
RELEASE 99-113
MARS CLIMATE ORBITER TEAM FINDS LIKELY CAUSE OF LOSS
A failure to recognize and correct an error in a transfer of information between
the Mars Climate Orbiter spacecraft team in Colorado and the mission navigation
team in California led to the loss of the spacecraft last week, preliminary findings
by NASA's Jet Propulsion Laboratory internal peer review indicate.
"People sometimes make errors," said Dr. Edward Weiler, NASA's Associate
Administrator for Space Science. "The problem here was not the error, it was the
failure of NASA's systems engineering, and the checks and balances in our processes to
detect the error. That's why we lost the spacecraft."
The peer review preliminary findings indicate that one team used English units (e.g.,
inches, feet and pounds) while the other used metric units for a key spacecraft
operation. This information was critical to the maneuvers required to place the
spacecraft in the proper Mars orbit.
"Our inability to recognize and correct this simple error has had major implications,"
said Dr. Edward Stone, director of the Jet Propulsion Laboratory. "We have underway a
thorough investigation to understand this issue."
On January 28, 1986, seven astronauts were killed when the space shuttle
they were piloting, the Challenger, exploded just over a minute into the
flight. The failure of the solid rocket booster O-rings to seal properly at low
temperature allowed hot combustion gases to leak from the side of the
booster and burn through the external fuel tank.
O-ring
Sayano–Shushenskaya hydroelectric power station
Catastrophe August 17, 2009
Mechanics
Studies mechanical motion of bodies and their interactions
•
-
Various forms of motion:
mechanical
electromagnetic
thermal, etc.
Mechanical form of motion: displacements of various bodies
relative to each other and changes of the shapes of the bodies
Interactions in mechanics are described as forces that change
the velocities of the bodies or lead to their deformation
For many centuries it was believed that all phenomena in nature
are mechanical
Then physics exploded with discoveries of a vast variety of
non-mechanical phenomena: electromagnetic, nuclear,
thermal, …
It turns out that at large scales all these complex interactions
cease to be important, and the motion is dominated by the force
of gravity and is described by the laws of mechanics.
N-body simulation Los-Alamos
Historical notes
• Ancient times: Greece, China, India, Arab countries
Driven by discoveries in astronomy or the need to build
machines and weapons
• Modern period: 15-17 centuries
- Galilei, Kepler, Huygens, Hooke, Newton
• 18th century: driven by tremendous development in
mathematics. Euler, D’Alembert, Lagrange, …
• 20th century: Nonlinear dynamics, chaos,
gas dynamics, etc. Poincare, Lyapunov, …
Quantum Mechanics; Theory of Relativity
Archimedes (3rd century B.C.), the law of
lever, the law of equilibrium for floating bodies
GIVE ME A PLACE TO STAND AND I WILL MOVE THE EARTH
Antikythera Mechanism decoded?!
• Found in 1901 near the Antikythera island in a Roman shipwreck dated 80 BC
• Remained a puzzle for over 100 years
• Recently deciphered using X-ray tomography, optical imaging, texture mapping
Nature, 30 November 2006 (page 587)
A sophisticated mechanical computer
Predicts:
• Lunar and solar cycles, taking into account ellipticity of the moon’s orbit
• Lunar and solar eclipses
• Accurate positions of the sun, moon, and planets
• Luni-solar calendar
It proves technical and scientific sophistication of the Greek
civilization that has been lost within Roman Empire
Next time when much simpler mechanisms of this kind appeared was in
Islamic countries in 1300 AD (Al Biruni)
Later they were imported to Europe and became clock mechanisms
Aryabhata the Elder
Born: 476 in Kusumapura (now Patna), India
Died: 550 in India
Most accurate value of Pi among ancients!
Add four to one hundred, multiply by eight and then add sixty-two thousand. the
result is approximately the circumference of a circle of diameter twenty thousand.
By this rule the relation of the circumference to diameter is given.
This gives π = 62832/20000 = 3.1416 which is a surprisingly accurate value:
π = 3.14159265 correct to 8 places!
Aryabhata gives a systematic treatment of the position of the planets in
space. He gave the circumference of the earth as 24 835 miles, which is an
excellent approximation to the currently accepted value of 24 902 miles. He
believed that the apparent rotation of the heavens was due to the axial
rotation of the Earth. This is a quite remarkable view which later
commentators could not bring themselves to follow and most changed the
text to save Aryabhata from what they thought were stupid errors!
Aryabhata believes that the Moon and planets shine by reflected sunlight.
He correctly explains the causes of eclipses of the Sun and the Moon.
Aryabhata calculated the Sidereal day (the rotation of the earth against the
fixed stars) as 23 hours 56 minutes and 4.1seconds; the modern value is
23:56:4.091. Similarly, his value for the length of the sidereal year at 365 days
6 hours 12 minutes 30 seconds is only 3 minutes 20 seconds longer than the
true value (over 365 days). The very notion of sidereal time was very
advanced for the time, so this kind of accurate computation speaks of a very
sophisticated understanding of the universe.
The 8th century Arabic edition of the Āryabhatīya was translated into Latin in
the 13th century, well before Copernicus. Through this translation, European
mathematicians may have learned methods for calculating sines and cosines
(exact to 4 significant digits!), as well as square and cube roots, and it is
likely that some of Aryabhata's results also influenced European astronomy.
Arab science
Science in Islamic world was built on the sciences of two great cultures,
the Greek and the Indian. Blending and expanding these often different
ideas led to a new science which later profoundly influenced Western
scientific exploration beginning in the Renaissance.
Al-Khwarizmi (9th century), the inventor of algebra. He based the
system on the Indian numbers borrowed by the Arabs (what we today
call Arabic numerals). Detailed positions of the sun and planets,
detailed map of the world.
Omar Khayyam was a great Persian scientist, philosopher, and poet
who lived from 1048-1131. He made outstanding contributions to
mathematics (general theory of cubic equations, conic sections, noneuclidean geometry, Pascal triangle, etc. ) He was ahead of his time by
at least 500 years. He compiled many astronomical tables and
performed a reformation of the calendar which was more accurate
than the Julian and came close to the Gregorian. An amazing feat was
his calculation of the year to be 365.24219858156 days long, which is
accurate to the 6th decimal place! Actually, 6th decimal place changes
over a person’s lifetime. Do you know why?
Samarkand: Marco Polo’s
“most perfectly beautiful city”
SOME ACCOMPLISHMENTS
1. Newton discovered the origin of
color.
2. He discovered the nature of gravity.
3. He invented calculus.
4. He invented the first reflecting
telescope.
5. He wrote and published the book
Principia Mathematica, which provided
a detailed explanation of the laws of
gravity and motion.
“Five Minute University”
All Newtonian mechanics can be formulated on a half of
this page:
A. Space and time
Our space is 3-dimensional and euclidean; our time is 1-dimensional and absolute
B. Galilean principle of relativity (Galileo’s ship!)
Laws of physics (and everything in the Universe) look the same for all
observers who move with a constant velocity with respect to each other.
C. Newton’s determinism
The motion of a body is uniquely determined by its initial position and velocity.
In particular, acceleration is a function of only the position and velocity:
a  f (r, v, t )  (1 / m)F(r, v, t )
Clockwork universe
Language of physics and engineering is
mathematics
This is a skill! Anyone can learn it
First week we will learn some calculus:
derivatives and integrals that we’ll need in this
course
We will need solid knowledge of vectors and
algebra all the time