Honors Physics

PHYS 141/HNRS 134

Physics Department

Cal Poly

San Luis Obispo

The Laws of Motion, Forces, Energy, Momentum
and the Conservation Laws

It is the most persistent and greatest adventure in human history, this search to understand the universe, how it works and where it came from. It is difficult to imagine that a handful of residents of a small planet circling an insignificant star in a small galaxy have as their aim a complete understanding of the entire universe, a small speck of creation truly believing it is capable of comprehending the whole.

- Murray Gell-Mann, Caltech physicist

Last updated: December 13, 2007

Instructor: Dr. Ron Brown - Physics Department

Textbook: PHYSICS for Scientists and Engineers - A Strategic Approach, by Randall D. Knight

Supplemental Notes: Physics 141 Supplemental Notes and Problems by Ronald Brown
(available in El Corral) <>

Course Syllabus
Calendar
Resources
Honors Physics Topics and Notes

General Physics: Mechanics

This is an introductory calculus-based course in classical mechanics. Topics include the description of motion, Newton's laws, the concepts of work and energy, impulse and momentum, and torque and angular momentum and the three conservation laws (energy, momentum, and angular momentum) that characterize the motions of objects and the principles that govern their motion.

This course is a special section of the Physics 141 course for students enrolled in the Cal Poly Honors Program. Emphasis will be on the concepts of classical mechanics with a goal to understand the principles that govern the motions of objects from baseballs to planets - and how those principles apply to solving problems.

This class is scheduled to meet four times per week for lectures, discussions, and problem solving. The format will include some lecture and some discussion each day - with occasional problem solving "workshops". Problems will be worked on both individually and in groups. It will be expected that you will come to the class having read the related material in the text and the supplemental notes and that you will have been working on the related problems - so that the work done in class is not your first exposure to that material.

You are welcome to come to my office to discuss the course or physics or anything else, for that matter, at any of my office hours or whenever it is convenient for you. If you can't meet my office hours - and can't find me just by dropping by, email me to set up a time to meet - EMAIL: rbrown@calpoly.edu

This course will deal with the basic ideas of motion - its description and the principles that govern it. The topics of the course include the description of motion, Newton's laws, the concepts of work and energy, impulse and momentum, torque and angular momentum - and the three conservation laws that govern that motion - and how to use those ideas and principles to solve problems. But it will also deal with much more. What you should gain from this course is an understanding of the way that science works - the critical method of how our ideas about nature are formulated. It is this that you will ultimately carry with you long after the specifics of the course have waned from your memory.

While studying how to solve problems involving motions of objects, we want to also consider grand questions like: Why do things fall with the same constant acceleration (and do they always)? What IS gravity? What is the law of gravity that ultimately governs the motions of falling objects, the planets, and the stars and galaxies? How can we know the mass of the earth (and why would we want to)? Why are the planetary orbits elliptical? (And by the way, how do we know that a planet is orbiting a small star 150 light-years away, anyway?) What can we know - and on what can we merely speculate?

Science is ultimately about ways of knowing - how we know what we know.

RESOURCES:

Textbook: PHYSICS for Scientists and Engineers by Randall Knight (Addison-Wesley, 2003)

Note: This textbook, authored by a Cal Poly physics professor, is a new text. It has a great conceptual development and includes a workbook to assist in developing both your conceptual understanding and your problem solving skills.

Supplemental Notes:

Physics 141 SUPPLEMENTAL NOTES AND PROBLEMS by Ronald Brown (El Corral)

The supplemental notes are intended to give you a different perspective on the material. The order will be different than the text in places. It is recommended that you read both presentations carefully.

References:

Student Study Guide

Any other introductory text in general physics.

Physics 141 SUPPLEMENTAL NOTES AND PROBLEMS - The supplement is intended to be used along with the text to relate the important ideas of the course. The supplement is available in El Corral with the physics textbooks.

The Supplement is about 100 pages covering kinematics, Newton's laws, work and energy, momentum, and rotational motion. The notes are intended to support the text - and focus on the fundamental concepts, ideas, and principles related to each of the topics and on tying the principles together and leaving you with a strong conceptual understanding. Each section concludes with a set of conceptual questions and problems to help your review.

Other books that make interesting reading (not a part of the course - but just to keep you engaged):

SIX EASY PIECES by Richard Feynman - This book is not an integral part of the course itself - but is a great read by one of the most gifted physicists and teachers of our time. It will give you a good sense of what science is about, of where physics is with respect to the other sciences, and then of the essential ideas of this course (and hence of the elements of physics).

THE GREAT PHYSICISTS FROM GALILEO TO EINSTEIN by George Gamov - This book is a collection of chapters on various scientists of whom you have heard - and describes the contributions they made to our understanding of the universe as a very readable level. The purpose in including it in the list of references is to give a sense of history to this human endeavor we call science. Some of you will find this an interesting addition to the course.

<> THE PHYSICISTS by C. P. Snow
<> ISAAC NEWTON by James Gleick
<> GALILEO'S DAUGHTER by Dava Sobel
<> THE FERMI SOLUTION by Hans Christian von Baeyer
<> RAINBOWS, SNOWFLAKES, AND QUARKS by Hans Christian von Baeyer

There are many others, of course, and any of these can contribute to your overall understanding of science in general and physics in particular.

Office Hours - Make good use of the access you have to your faculty in all courses. Don't wait until you are in trouble in a class to seek help. When you don't understand something, ask! If you just want to discuss the ideas or look for reassurance on your line of reasoning, make use of office hours. If you cannot get to office hours for some reason, contact your instructor after class or by email to set up a time to meet - or just stop by the office.

Private Tutoring - Individual arrangements can be made with Physics majors available for tutoring in Sci. Bldg. room E-25 (known affectionately as "h-bar" - a physics in-joke)

Drop-In Help - Those same tutors will also usually help for free if you just stop by "h-bar" or go to the Learning Center.

Mathematics and Science Learning Center - The Learning Center will be open starting the second week of classes. - Faculty and student tutors from Physics department hold office hours in the Learning Center - Sci. Bldg. C-20. It is a good place to go to work HW (with help immediately available) or to ask questions of whoever is "on call".

Learning Center Hours: Mon. 9 am - noon; Tues., Wed. 9 am - 2 pm; Thurs. noon - pm; Fri. 9 am - noon.

NOTE: Hours may change when Center opens the second week of classes.

Useful Links: The following are links to three very helpful discussions on how to approach studying physics and the necessary problem solving that goes with studying physics, written by Dr. Dan Styer, Physics Dept., Oberlin College.

Tips for Studying Physics
The Whys and Hows of Physics Problems
Solving Problems in Physics

HOMEWORK: The questions, exercises, and problems on the assignment sheet are to help you understand the material. You should do the problems systematically and carefully in a HW notebook - and ask questions about problems you have difficulty with. Solutions will be posted on the web: Problem Solutions

Posted Solutions and Hints - Selected problem hints and/or solutions will be posted on the bulletin board just outside room E-47 in the Science Bldg (Bldg.52).

PHYS 141 / HNRS 134 SECTION NOTES:

[Look here for comments related to the Honors 134 section of Physics 141.]

This class is scheduled to meet four times per week for lecture, discussion, and problem solving. The format will include some lecture and some discussion each day - with occasional problem solving "workshops". Problems will be worked on both individually and in groups. It will be expected that you will attend class regularly having read the related material in the text and the supplemental notes and that you will have worked on problems (those in the text, the workbook, the supplemental notes) - so that the work done in class is not your first exposure to that material. Most of the homework that is actually collected will be problems from the supplemental notes or from individual problem set worksheets.

You are welcome to come to my office to discuss the course or physics or anything else, for that matter, at any of my office hours or whenever it is convenient for you. If you can't meet my office hours - and can't find me just by dropping by, email me to set up a time to meet.

The First Week

Following an introduction to the class, expect a diagnostic pre-test on mathematical ideas (and maybe even some physics ideas) to be handed out and collected the second class meeting - to be done independently. It's purpose is to see where you are, what you are bringing in with you, and what of that you are comfortable with. It won't "count" toward your grade in any way, it is just diagnostic - but will lead to a discussion of the tools and ideas that we will need in this course.

The first meeting will be an introduction and description of the course, its goals and expectations and some discussion of how problems are solved - the general approaches, the use of equations, how to make estimates, etc. By Thursday, you should have read the introductory section of the Supplemental Notes and Problems and be reading the textbook and starting to address some problems.

Then we will begin what is the central theme of this course: Forces and how forces act. By Friday, you should have read through the second section of the Supplement on Forces. In particular, look at the discussion of the nature of forces as interactions between objects.

Week No. 2:

We will develop the kinematics equations in one-dimension and make the connection between the equations, the description of motion, and the graphical representations of the motion. The discussion will include free-fall problems (which are the basis for all projectile motion problems, as we will see). By Friday, we will return to the mathematical description of vectors, so that the mathematical development of the one-dimensional motion can be extended to two and three dimensions.

There will be a short quiz on the first week or so of the material.

Week No. 3:

In the first couple of chapters, we have been building the tools needed to deal with Newton's laws. This week, we will start making the connection between the forces that act on an object and the resulting changes in motion. On Wednesday, we will talk about any of the projectile motion problems that offered difficulty - and will extend the discussion of two dimensional motion to circular motion problems (something we will come back to in later chapters). That discussion will lead to Newton's development of his three laws of motion (and even his law of gravity). Given the background of how to describe motion in two dimensions (which, in general, requires making use of vector notation), and the understanding that forces are always interactions between two objects, we will be able to show how knowing the forces that act on an object will lead to a complete description of its motion.

There will be a short quiz on kinematics during the first part of class. It will just be one or two problems that are based on the ideas covered so far on the description of motion in one and two dimensions. The problems will be similar to those you have already seen in the HW and others in the Supplemental Notes.