Honors 301: Special Theory of Relativity

Honors 301: Special Theory of Relativity
Winter 2008-2009


Prof. Michael S. Vogeley
Department of Physics
Office: 811 Disque Hall
Phone: 215-895-2710
Email: vogeley@drexel.edu

Announcements
Course Meetings
Syllabus
Course Description and Philosophy
Grading
Reading Assignments
Lecture Notes
Homework Assignments
Homework Hints
Homework Solutions
Exams
Midterm Solutions
Course Schedule

Announcements

All homework solutions and lecture notes are now posted below.

The FINAL EXAM is on Tuesday, March 17 3:30-5:30 p.m. in Stratton 101. Open book, open note. Bring a calculator.

Welcome to the home page for Honors 301, Special Theory of Relativity. Watch this space for important announcements and useful hints.

Send me email to ask questions about homework assignments and the course readings so that I can give you timely feedback and send any relevant homework hints to everyone else in the class. To ensure that you receive email sent to the class, you must read email sent to your official Drexel email address.

All lecture notes and homework solutions will be distributed as PDF files from this web page. No paper copies will be handed out.

Course Meetings

Lecture times: Tuesday and Thursday 9:30-10:50 a.m. in McAlister 5051 (the Honors Program seminar room).
If you will be unable to attend class, please notify me ahead of time or contact me as soon as possible.

Office hours: 3:30 - 4:30 p.m. Wednesdays (or by appointment).

Syllabus

This web page is the syllabus. If you are reading a printed copy, you may find the online version at www.physics.drexel.edu/courses/SpecialRel (note carefully the capitalization!).

Course Description and Philosophy

Einstein's Theory of Special Relativity is one of the greatest advances of modern science. This theory revolutionized our view of the physical world, unifying space and time, electricity and magnetism, energy and momentum. In this course we will explore and explain many of the sometimes counterintuitive but fundamental aspects of SR. At the end of the course, we will also introduce Einstein's General Theory of Relativity.

Relativity is sometimes thought of as "far out" science applicable only to extreme astrophysical circumstances. In fact, understanding of both Special and General Relativity is necessary for operation of several systems that we have come to rely on. Operation of satellites in orbit around the Earth requires that we compute the effects of both Special and General relativity. Systems like GPS would utterly fail without doing so (which means that most of our advanced weapons guidance systems would fail). I'll show you a "Handbook on Relativistic Time Transfer" that proves this point.

Topics that will be covered in this course include

The most important goal of this course is that you further develop your ability to think clearly and quantitatively about the physical world. It is unlikely that your daily life and work will require you to instantly recall the equations that we will use. However, well-developed physical insight will serve you well in whatever endeavor you choose. Einstein was fond of the ``gedankenexperiment'' - the thought experiment - as a means of gaining insight on a problem. I hope that this course will likewise stretch your imagination.

Grading

Grades will be based on the following weighting of different components of the course:
Homework: 30%
Midterm Exam: 25%
Final Exam: 35%
Class Participation: 10%

The Class Participation component will be partially based on attendance. Extra credit will be given to new theories of spacetime and gravity that result in published papers in the Physical Review.

Reading Assigments

Required reading for the course is "Spacetime Physics: Introduction to Special Relativity, Second Edition" by E. F. Taylor and J. A. Wheeler (W. H. Freeman: New York). Written by master physics teacher Edwin Taylor and one of the preeminent physicists of our time, John Wheeler (who coined the term ``Black Hole''), this text is chock full of clever examples and problems that teach relativity in terms of geometry. Never mind the annoying bird.

Please read the assignments before class and prepare to ask questions.

See the Course Schedule below for the weekly reading assignments.

Good biographies about Einstein:
Subtle is the Lord by Abraham Pais (best for the science) and Einstein: His Life and Universe by Walter Isaacson (most recent comprehensive biography).

Lecture Notes

PDF files of typeset lecture notes may be downloaded here (no paper copies will be distributed). These notes are not a substitute for reading the textbook or attending class.

Lecture notes 1 (PDF file)

Lecture notes 2 (PDF file)

Lecture notes 3 (PDF file)

Lecture notes 4 (PDF file)

Lecture notes 5 (PDF file)

Lecture notes 6 (PDF file)

Lecture notes 7 (PDF file)

Lecture notes 8 (PDF file)

Lecture notes 9 (PDF file)

Lecture notes 10 (PDF file)


Homework Assignments (check for hints below)

There will be 7 homework assignments. These will typically be due at the start of class one week after being assigned. Plan ahead. Late homework will not be accepted and there will be no ``dropped homeworks.''

Solutions to the homework will be posted on the web page on the due date; that is why late homework will not be accepted. Please strive to present your answers in a neat, workmanlike fashion; the clarity of your solutions will count toward your grade.

Science is a collaborative enterprise and you are encouraged to discuss the homework problems. Brainstorming is fun! (Even Einstein received help.) But you and you alone are responsible for the work that you turn in. In other words, you may talk about the problems with your classmates, but you must write out your own solutions. Serious breaches of this policy will result in homework scores being dividing by the number of ``participants.'' Show your work. Answers without justification will receive no credit.

Homework 1:
Chapter 1: problems 4a,b,c, 5, 8, 11, 12
Due in class Thursday, January 15.

Homework 2:
Chapter 2: problems 4, 9, 10, 11, 13
Due in class Thursday, January 22.

Homework 3:
Chapter 3: problems 2, 4 (explain your answer to each!), 12 (a, b only), 14 (a, b only), 17
Due in class Thursday, January 29

Homework 4:
Chapter L: 6 (part a only), 7, 8
Due in class Tuesday, February 12

Homework 5: Chapter 4: 4-1 (Just one problem! Explanations, please. The answers are in the book.)
Due in class Thursday, February 19

Homework 6: Chapter 5: 5-2, 5-4, 5-6
Due in class Thursday, February 26

Homework 7: Chapter 6: 6-1, 6-3, 6-4
Due in class Thursday, March 5.

Homework 8:
Chapter 7: 7-2, 7-8 (ignore the bit about "mass handles")
Due in class Thursday, March 15

Homework Hints

Hints will be posted here as I think of useful info or in response to your questions.

Homework hints 1:
In problem 4, note that the distances are given in light-seconds, so it's straightforward to measure both distance and time in seconds.

Do Problem 5 using units of years and light-years. Think carefully, what is the speed of light in units of light-years/year?

In problem 11-b the point is to ignore Special Relativity for the moment and consider what happens if the time interval for an observer moving with the muons were the same as an observer in the Earth frame. In the rest of the problem, "rocket frame" means moving with the muons.

12-a likewise asks that you momentarily suspend your knowledge of Special Relativity.

In 12-b, try to use the equivalance of the spacetime intervals to get an equation for the time dilation effect. Write down the full equation for the equivalence of the square of the spacetime intervals in the moving particle and lab frames. Substitute in or set to zero those values that you know. Simplify that equation as much as possible. The distance actually travelled in the lab frame is simply the velocity of the particles times the time interval in the lab frame.

Homework hints 2:
Problem 10: Remember that F=ma, thus a=F/m. And recall that the distance travelled under constant acceleration a is x=(1/2)at**2. Assume a mass of 10 grams for the ball bearing in part (b).

Homework hints 3:
Problem 12 (part b): Note that the plane must overcome a crosswind, so its velocity must have a component that is perpendicular to the intended direction of travel. Then use the Pythagorean Theorem.

Problem 14: Think about what is actually moving. Is any physical object or information being transmitted faster than the speed of light? In part (a), use trigonometry to determine how far the intersection point moves in x as the rod moves in x, then write the equation for the x velocity of that intersection as a function of the y velocity of the rod and the angle of intersection. Note that the velocity had better be zero if the rod is vertical (theta=90 deg).

Problem 17: Note that in parts a, b, and c we pretend that the observer has no depth perception.

Homework hints 4:
Chapter L, ALL PROBLEMS: Assume that the rocket moves in the x direction. Remember that distances transverse to the direction of motion do not change. And note carefully that time dilation always occurs, regardless of which direction something is moving.

Homework Solutions

HW1 solutions (PDF file)

HW2 solutions (PDF file)

HW3 solutions (PDF file)

HW4 solutions (PDF file)

HW5 solutions (PDF file)

HW6 solutions (PDF file)

HW7 solutions (PDF file)

HW8 solutions (PDF file)

Exams

We'll have one Midterm exam and a Final. The Midterm will be given during class time on Thursday, February 5. The Midterm exam will include material covered in weeks 1 through 4.

The Final will be 2 hours long: Tuesday, March 17 3:30-5:30 p.m. in Stratton 101. The Final will include material from the entire course, but with emphasis on the second half of the course. Please note that material from Week 10 is not covered in any homework, but will be covered in the final.

The exams will be open book and open note. But you'll find that an open mind will be most helpful. Calculators may be used for simple arithmetic operations. The use of calculators for execution of ``memorized'' formulae is specifically not allowed. Ask me if you are uncertain about this policy.

Midterm Solutions

Solutions will be posted here after the midterm exam.

midterm solutions (PDF)

Course Schedule

Please note the following schedule of readings and assignments. This schedule may be revised, so you should recheck this web page. Notation of "HW#" indicates that a homework will be assigned that week. Most of the homeworks will be due on the following Thursday. Exact due dates for the homework will be announced in class. You should do the indicated reading before class.

Week Class Dates Reading Homework Exams
1 January 6, 8 ch. 1 HW1
2 January 13, 15 ch. 2 HW2
3 January 20, 22 ch. 3
4 January 27, 29 ch. LT HW3
5 February 3, 5 ch. 4 HW4 Midterm (Feb. 5)
6 February 10, 12 ch. 5
7 February 17, 19 ch. 6 HW5
8 February 24, 26 ch. 7 HW6
9 March 3, 5 ch. 8 HW7
10 March 10, 12 ch. 9
11 No Class Final Exam, TBA

Last update: March 12, 2009