Why do the homework?
Since you're juniors, you've all figured this out by now.
But, I'll say it anyway...
I can't emphasize enough the importance of working the problems. In some of your classes homework is primarily evaluative; the point is for you to demonstrate what you've learned from the readings and lectures. In physics the homeworks are primarily instructional; you learn physics primarily by doing working problems. You must work the problems, think about the results, and understand any mistakes you've made if you wish to attain the type of understanding of the subject required of a working physicist. In at nutshell: If you can't work problems you don't know physics. I (or a grader) will grade the problems, and I'll hand out solutions. I encourage you to read the solutions and understand any mistakes immediately. If something doesn't make sense, ask me about it right away---don't wait until right before an exam.
Homework extensions
If you've got a good reason why you need an extension,
come talk to me in advance. I'll usually grant the extension
for some additional reasonable amount of time that we agree upon.
However,
I will not grant a homework extension without penalty if you ask for
it on the day the homework is due, so don't ask for one.
In general,
life will be easier for both of us if you do
your best to finish the problem set on time and hand
in as much as you've been able to complete by the deadline.
[If you need such a last-minute or post-facto extension due
to extenuating circumstances (e.g. death in the family, sudden
illness, travel problem), consult the Dean of Students
or your Class Dean formally make such a request to me and suggest
a rescheduled due date. You should also take this route if you
need an extension but you don't want to tell me why (say, it's for
personal or legal reasons). If you explain your reason to a Dean
and the Dean tells me it's OK, that's good enough for me.]
The College requires that all written work for a course except for a final be submitted by 5 pm on the last day of classes. The physics department takes this deadline seriously. After that day/time, no homework will be accepted.
The roles of lectures and textbooks
Lecture will not be a regurgitation of the text, a summary of all
you need to know for the course, or a how-to guide for the homework.
Rather, I'll try delve deeper into selected points.
In lecture I'll cover material and do demonstrations
related to the readings, but I won't feel obliged to
be comprehensive in those places where I feel the text is adequate
and I may focus only on a few points that I feel are particularly
interesting or subtle. You shouldn't expect to understand what's
going on without close study of the readings, and you
should come to class with questions you have
on the readings. Further, after we settle into the semester
a bit, I expect the classes will become less lecture-oriented
and more participatory; it will be difficult to reap
the maximum benefit from that format if you're not
sufficiently prepared to fully participate.
For the problems you can't solve, talk to classmates, attend the problem sessions, or ask me. When you ask me, either try to give you just enough of a hint to get you through, or I'll guide you through the problem with a series of leading questions. I'll never just tell you how to do it. If you run out of time and don't finish the set, start earlier next week. When the solutions come out, look over them right away, before you've forgotten all of the points you were confused about. You think you'll just get clear on it before the next exam, but there's never as much time as you think.
On the other hand, if you find the class too slow for your liking, if you have questions that you aren't getting answers to, if you'd like more detail, if you are frustrated that we aren't digging deeply enough, if you crave more applications, come talk to me. I'm very happy to provide you with additional materials or explanations that will will stimulate you and challenge you at whatever level you can handle.
One word of warning: Amherst College students tend to have lots of extracurriculars of all types. I support this, and I am occasionally willing to be flexible to facilitate your participation in range of activities, but don't let your extracurriculars overshadow your academics. If you become concerned that your courses are getting in the way of your extracurriculars, you've got the wrong mindset. Remember why you're here.
Mathematica Tutorials
We will use Mathematica fairly extensively in the homework,
to obtain numerical solutions to problems that are not
analytically solvable and to simplify plotting of results.
If you've never used Mathematica before, or haven't used it much,
the tutorials will help you get started.
They were written by Professor Emeritus Bob Hilborn and revised by
Rebecca Erwin '02. If you download the file and save it to the
desktop with a .nb suffix in the name, your computer will recognize it
as a Mathematica notebook and will start up Mathematica automatically
when you double-click on the icon,
provided you have Mathematica installed. Mathematica is installed on
lots of the college's public machines, including
on the computers in the Physics
Department computer lab. Alternately, you can pay the $140 or so
to buy the student version.
Week | Notes | Hmwk | Other |
1. September 1 | Sept 2: Intro and Logistics / Space, time, and vectors Scope of classical mechanics, and scope of the course. Space and time: the background manifold we'll use. Geometrical vectors: define vectors as quantities that transform under rotations as the displacement. [Handouts: Student information sheet ] Sept 4: More about vectors Write general vectors in terms of orthonormal basis vectors. Einstein summation convention. In 2D, compare, contrast, and convert between Cartesian and polar basis vectors. Products of vectors and the geometrical interpretation: scalar and vector products. Levi-Civita symbol and Kronecker delta. Differentiation of vector functions: definition, versions of familiar calculus rules. Beware: basis vectors in non-cartesian coordinates have non-trivial derivatives! [Handouts: Vector analysis with diagrams (pp. 7-11 of Stedman's Diagrammatic Methods in Group Theory)] |
Read: Kibble, Chap. 1 and Appendix A Problems: [Due Tuesday 9/9/08, 11:59 pm] Appendix A: 7 Chap. 2: 3, 7 |
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2. September 8 | Sept 9: Vectors / Newton's Laws Differentiation of vectors: position, velocity, and acceleration in polar coordinates. Diagrammatic argument that derivatives of radial and polar vectors "make sense." Interpretation of terms in expression for acceleration vector. Finite rotations are not vectors (infinitesimal rotations are). Reference frames defined (inertial frames particularly important). Mass and force defined rather casually. Newton I addresses natural state of motion, serves to define inertial frames. Newton II is the "workhorse." Newton III (strong form and weak form). Consequence of Newton III: conservation of linear momentum for composite systems. Failures of NIII (in relativity, in electrodynamics). Linear motion: conservative forces and energy conservation. Sept 11: Linear Motion Conservative forces and conservation of energy: When F=F(x), can always find a first integral of motion (fn of x and v) which is constant in time. Show that T+V=E is constant in time. Show how the potential energy landscape can be used to give qualitative description of motion evey without explicit solution (stable and unstable equilibria, turning points). Small oscillations about equilibrium: Taylor expand about equilibrium point. Only second order and higher terms in small displacement are nonzero. If equilibrium is stable, displacements may remain small for all time; not so if unstable. In stable equilibrium, leading term is usually quadratic: harmonic oscillator potential. Harmonic oscillator potential: possible motions for SHO and inverted SHO potentials. Equation of motion. 2nd order linear ODE--general solution has two linearly independent terms and two constants of integration. Linear ODEs satisfy superposition principle. Show that superposition of solutions is also a solution for linear equations, and that it's not true in general for nonlinear equations. Guess solutions of exponential form, solve. |
Read: Kibble, Chap. 2 Problems: Kibble, Chap. 2: 8, 9, 15, 20, 26, 30 |
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3. September 15 | Sept 16: Title Sept 18: Title |
Read: Problems: |
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4. September 22 | Sept 23: Title Sept 25: Title |
Read: Problems: |
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5. September 29 | Sept 30: Title Oct 1: Exam 1 (7-9 pm) Oct 2: Title |
Read: Problems: |
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6. October 6 | Oct 7: Title Oct 9: Title |
Read: Problems: |
Exam practice: P43F04 exam 1 |
7. October 13 | Oct 14: Fall Break Oct 16: Title |
Read: Problems: |
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8. October 20 | Oct 21: Title Oct 23: Title |
Read: Problems: |
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9. October 27 | Oct 28: Title Oct 30: Title |
Read: Problems: |
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10. November 3 | Nov 4: Title Nov 6: Title |
Read: Problems: |
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11. November 10 | Nov 11: Title Nov 13: Title |
Read: Problems: |
Exam practice:
P43F04 exam 2 |
12. November 17 | Nov 18: Title Nov 19 (evening): Exam 2 Nov 20: Title |
Read: Problems: |
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13. December 1 | Dec 2: Title Dec 4: Title |
Read: Problems: |
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14. December 8 | Dec 9: Dec 11: Reading period |
Read: Problems: |