Physics 218 Sections 807-809

Instructor: Dr. Alexey Belyanin

Homepage http://faculty.physics.tamu.edu/belyanin/P218/Office: Engineering/Physics Office Tower (ENPO), Room 509Phone 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%

•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.

Grade Policy (cont)

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!

HomeworkYou 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.

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 LOSSA 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."

NASA PRESS RELEASE 09/30/1999

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 stationCatastrophe August 17, 2009

Mechanics

• 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

Studies mechanical motion of bodies and their interactions

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

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

It proves technical and scientific sophistication of the Greek civilization that has been lost within Roman Empire

Aryabhata the Elder Born: 476 in Kusumapura (now Patna), IndiaDied: 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 scienceScience 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, non-euclidean 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 timeOur 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 determinismThe 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:

),,()/1(),,( tmt vrFvrfa

Clockwork universe

Language of physics and engineering is mathematics

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

This is a skill! Anyone can learn it