Fall 2018

Dr. Johnny B. Holmes

Basics (course description, goals, topics, grading, etc.)

Regular (collected, written) Homework (introduction, format, assignments, example)

Computer Homework (introduction, assignments, download programs)

Overview (calendar of due dates for homework and tests)

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Description, goals, topics


Tentative Test Schedule

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Description, goals, topics

A second course in physics covering electric forces, electric fields, voltage, capacitance, current, resistance, magnetic forces, magnetic fields, induction, oscillations, and waves. Prerequisite: PHYS 150. Corequisite: PHYS 251L.

TEXT: none required;  and University Physics text will have the material;  recommended:  PHYSICS for Scientists and Engineers / with Modern Physics, any edition, by Serway.  There is also a free on-line text at: free on-line text .

INSTRUCTOR: Dr. Johnny B. Holmes, Professor of Physics

OFFICE: AH 004; office phone 321-3448; home phone: 383-9045; e-mail:

GOALS: The course is designed to:

  1. Teach the fundamental aspects of electric and magnetic fields
    1. since these form the basis for understanding atoms, molecules and solids;
    2. since these form the basis for understanding electrical circuitry and power systems;
    3. to provide a foundation for future courses;
    4. to provide a fund of concepts, images, and metaphors that can be utilized to image how other things in the world might work; and
    5. to provide the basic knowledge and understanding of the scientific basis of our technological society so that you may become an informed and effective citizen.
  2. Demonstrate how physical phenomena can be organized and described both qualitatively and quantitatively by theory.
  3. Reinforce the application of analytical reasoning.


  1. Basic algebra, solution of simultaneous equations, and trigonometry
  2. Definition of the derivative and basic rules of differentiation
  3. Definition of the integral and basic rules of integration
  4. Newton's Laws of Motion and Newton's Law of Gravity.
  5. Concepts of kinetic and potential energy, and law of conservation of Energy


  1. Electric forces and electric fields, Gauss' Law (7 classes)
  2. Electric potential, resistors, capacitors and circuits (8 classes)
  3. Magnetic fields and Ampere's law (8 classes)
  4. Induction and magnetic properties (8 classes)
  5. Waves and oscillations, Maxwell's equations (7 classes)

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GRADING: grades (each based on 100 points) description

  • 5 . . . 5 tests each worth 1 grade (see tentative schedule below)
  • 1 . . . 9 collected homework assignments, together worth 1 grade (see below)
    You MUST HAVE A 65% OR BETTER on the collected homework to pass the course!
  • 2 . . . 16 computer homework assignments in two sets (see below)
  • 3 . . . the final exam counts as three grades
    11 . . . TOTAL (final average based on average of these ten grades)
  • -1 . . . I will drop your lowest grade (not counting regular or computer homework) if you have 3 or fewer absences.  If the final exam is the lowest, it will count as 2 instead of 3 grades.
    10 . . . ADJUSTED TOTAL The average of these ten (or eleven) grades will determine your final average. Your final grade will be given based on the following ranges of your final average:

A: 93­ to 100; B: 82 to ­93; C: 70­ to 82; D: 65 to ­70; F: 0­ to 65.

The tests will come essentially from the homework (both collected and uncollected - see the study guides), the computer assignments, and material covered in class. The final exam will come essentially from the five previous tests.

The course emphasizes problem solving rather than memorization. You will be permitted to bring in one 8˝" x 11" sheet of paper with whatever you wish on one side for each test. You may bring in two sheets (or one sheet both sides) for the final exam. However, the information on it must be in your own handwriting. No duplicated material will be permitted. Calculators are permitted, and even recommended.  Connection to the internet during any test is not permitted. Hands, calculator, and eyes should be on the desk and not in your lap during tests.  Questions about grading on a test should be asked within one week of getting the test back, but questions about the physics can be asked anytime.

You are expected to attend class since important concepts will be discussed in ways the text will complement but not duplicate. If you have more than three absences I will not drop your lowest test score as mentioned above. If you miss a test, then you may request a make-up test. If I grant the request, a 10% penalty will be imposed. (If you have less than four absences you may drop this test from your average.) However, if you know you will miss a test, you may arrange to take the test early with no penalty. I do need at least 24 hour notice so that I have time to prepare the test.

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Sept.  7


Test 1 over Electric Forces and Electric Fields

Sept. 28


Test 2 over Electric Potential & Basic Circuits0

Oct. 26


Test 3 over Magnetism

Nov. 16


Test 4 over Electromagnetism

Dec.  7


Test 5 over Electromagnetic Waves


Final Exam (comprehensive)

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An Example

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The purpose of the collected homework is two­fold: (1) to enhance your problem solving skills; and (2) to enhance your communication skills.

You must get at least a 65% on the collected homework to pass the course!

The collected homework (which counts as one of your ten [or eleven] grades) consists of a set of 9 problems of which one problem will be due most every Wednesday (see schedule below). Each problem will be worth 11 points giving a total of 9 x 11 = 99 points. If you get the required 64 points (or more), I will add a point to your grade to make the homework grade be based on 100 (like all the others).

If you do not turn in the problem by the due date, you may turn it in before the last day of class but there will be a late penalty of 2 points.

If minor errors (e.g., dumb algebra mistake, incomplete units, occasional grammar error) are detected, points will be subtracted. If major errors are detected (e.g., few if any units, unclear diagram, start with specialized equations rather than basic equations), the problem will be marked REDO and no credit will be awarded unless it is redone in an acceptable manner and resubmitted by the last class. Problems will normally be returned to you at the next class so that you have time to correct the major errors. If you get any grade less than 9 on any problem, you may re-submit that problem before the last class for up to 9 points credit.

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Format for regular collected homework:

The collected homework must be done according to the following format: [BE SURE TO NUMBER EACH OF THE SEVEN STEPS FOR EACH PROBLEM.]

1) I want to and I can: State this at the beginning of the problem. Questions you should ask yourself to confirm this attitude include: Do I want to pass the course? Do I want to learn something? Do I want to see how well I know something and understand the concepts? Have I read the chapter? Have I reviewed my notes from class? Am I willing to seek help?

2) Define the situation:

  1. State what you are given (for each piece of information define a symbol and then set that symbol equal to the value you are given).
  2. Draw a diagram and put your knowns and unknowns on the diagram. I consider this VERY IMPORTANT!

3) State the objective:

  1. State what you are looking for (use a symbol or symbols that will be found in the equations you will use and define those symbols).
  2. State what units the quantity or quantities should have.

4) Explore the options:

  1. State the basic equations or principles (by name only) that could be used. Note: only definitions or equations on the study guide are allowed.
  2. State any other way you might accomplish the objective.

5) Plan your method of attack: Outline the procedure you intend to follow. Write down only the major equations to be used. Do not include all the individual steps that it will take.

6) Show the algebra (or trig or calculus) work to solve the problem. Be sure to show units in your calculations!

7) Look back:

  1. State your answer with the appropriate units.
  2. Check your units to see if they match those you listed in part 3b above.
  3. Compare your answer to known benchmarks whenever possible.

If there is more than one part to the problem, do the above for each part. Sometimes the problem will have parts a,b,c that actually involve finding different quantities in the same problem, and sometimes the parts a,b,c will actually be different problems. It is up to you to distinguish the two cases!

Be sure your homework is neat and legible. Points may be taken off or the homework may not even be accepted if the work is not neat and easily legible!

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The Assignments:







Aug. 22




Aug. 29




Sept. 12




Sept. 19




Oct.  3




Oct. 10




Oct  31




Nov. 7




Nov. 28


[S­ indicates a letter problem from the study guides.] Alternative problems may be assigned in class if the pace of the class does not match the one anticipated.

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1) I want to and I can.

2) Define the situation:

  1. Given: length of person, yperson = 6 ft; mirror.
  2. Diagram:


3) State the Objective:

  1. Looking for useful length of mirror, yuseful
  2. Units: length should have units of feet.

4) Explore the Options:

  1. Equations: qincident = qreflected (law of reflection) Eq. (1)
    tan q = opposite/adjacent (trig def.) Eq. (2)
    yfloor + ytop = yperson (def. from diagram) Eq. (3)
  2. Other ways: obtain a long mirror and have someone mark on the mirror where you see your shoes and where on the mirror you see the top of your head.

5) Plan the method of attack:
Draw lines from eyes to mirror and back to shoes such that qincident = qreflected. Find position on mirror where ray of light from shoes (on the floor) strikes on way to eye; repeat procedure for top of head. Measure distance between these two points. (Any portion of mirror below the first point or above the second point is not useful for present purposes.)

6) Take action:

  1. draw lines from eye to mirror and from mirror to shoes;
  2. identify qincident and qreflected; note that qincident = qreflected;
  3. extend normal line used to specify q's to create two triangles;
  4. from diagram, note that since qincident = qreflected (Eq. 1) that
    tan qincident = tan qreflected ; therefore y1 /x = y2 /x (using Eq. 2);
  5. therefore, y1 = y2; and since y1 + y2 = yfloor , y2 = 1/2 yfloor;
  6. the same procedure can be used for the distance needed for the top of the head;
  7. therefore, yuseful = 1/2 yperson = 1/2 6 ft = 3 ft.

7) Look back:

  1. Answer: yuseful = 1/2 yperson = 3 ft.
  2. Units are in feet which corresponds to 3b.
  3. The useful length depends on the height of the person which is reasonable.
  4. Note: the useful length does NOT depend on the distance (x) from the object to the mirror. Is this correct? If this surprises you, check it out for yourself to see if you or the theory is correct!

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Introduction (purpose, how to get and use the programs)


download programs (this takes you to another CBU site)

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Introduction to Computer Homework Assignments

The purpose of the computer assignments is two­fold: (1) to give you (graded) practice applying the concepts taught in class (with immediate feedback as to whether you are correct or not), and (2) to encourage you to be accurate in your calculations (no partial credit given for wrong answers ­ instead a chance to do the whole set again [but with different numbers]).

The computer homework set, which will count as two of your ten or eleven grades, consists of 15 separate computer programs (schedule is below).

To do any of the programs:
1.  First create a directory in your computer called Physics.
For Mac users, use a windows emulator, or follow the instructions for downloading either the WINE utility or the DOSBOX utility before proceeding with step 2 below.
2.  Go to the course website at: Download (SAVE not RUN) to your Physics directory (created in Step 1) your own copy of PV0WIN.EXE (windows or Mac WINE) or PV0DOS.EXE (Mac with DOSBOX) from the course web page, or see your instructor about making your own copy on a flash drive.  Later you will need to download PV2WIN.EXE, PV3WIN.EXE, and PV4WIN.EXE (or PV2DOS.EXE, PV3DOS.EXE, and PV4DOS.EXE for Macs with DOSBOX) to your Physics directory.
3.  To begin running the programs, go to your Physics directory, and double click on the PV0WIN.EXE icon, or for Macs with DOSBOX, drag your PV0DOS.EXE icon into the DOSBOX icon.
4.  When the program begins, it will ask you if this is your first time or if this is a repeat.  The first time you run the program, type F for first time.  It should show the path to your Physics directory.
5.  After verifying the path, you will be asked to enter your course number [PHYS 251, choice d], then your instructor [Dr. Holmes, choice h], then your section [A, choice a], then enter your name: Last First (use no commas). The computer will then ask you to verify your course and name - if it is correct as displayed, simply press return; if not, re-enter in the course or name.  Later, if you type R for repeat instead of F for first, you will not have to enter this info.
6.  The computer will then display the menu of programs on the volume you have chosen. Simply type in the number of the program you wish to run and then press Enter to confirm your choice. From here on out, simply follow the directions on the screen.
7.  How I read your responses:  Each time you run the program, the computer will either create a file called STRES.DAT or update this file if it already exists. When you are finished, you will have to get this file, called STRES.DAT , which should be in your Physics directory, to me to record your grades.  You must send the responses to me either by attaching the file: STRES.DAT to an e-mail message to me (at or by copying the STRES.DAT file to a flash drive and giving the flash drive to me to read.
8.  I will indicate to you by return e-mail your current computer score and I will also indicate to you your current computer score on your written homework and on your tests when I hand these back to you. There will be a CH1 (and later a CH2) followed by a number to indicate your computer homework score(s).

Each of the programs asks questions or allows you to do certain things. Your answers or results are recorded on the STRES.DAT file as you do them. This allows me to grade your computer homework.

Each assignment may be performed as often as you like. I will only count your best effort, so feel free to do it over and over until you get it perfect. If you get the first 9 questions correct but miss the tenth one, you need to redo the whole program and get all 10 questions correct for full credit. The reason behind this is so that you will consider whether your answers to the questions are correct before you enter them in (step 7 of the problem solving paradigm).

The due date indicates when it should be completed if you are to remain on schedule and wish full credit. If you do the assignment after the due date but before the last day of classes, you will get 80% credit. No credit will be awarded for anything submitted after the last class.

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Schedule of Computer Assignments

SETS #1 and #2  (for two grades)



due date





F Aug. 24





M Aug. 27




Electric Fields

F Aug. 31




Gauss’ Law

W Sept. 5




Test #1 on Friday, Sept. 7





Energy & Power

M Sept. 10




Electric Potentials

F Sept. 14




Electric Deflection

F Sept. 21




Resistors – Advanced

M Sept. 24




Capacitors – Advanced

W Sept. 26




Test #2 on Friday, Sept. 28





TOTAL for set #1





Magnetic Forces





Magnetic Deflection

F Oct. 5




Magnetic Fields

F Oct. 12




Test #3 on Friday, Oct. 26





Induction (Lenz's Law)

F Nov. 2





F Nov. 9




Test #4 on Friday, Nov. 16





Waves/Doppler Effect

F Nov. 30




Electromagnetic Waves

W Dec. 5




Test #5 on Friday, Dec. 7





TOTAL for set #2




NOTE: BONUS - If you get 100/100 on either or both of the computer assignment sets, 10 points will be added to your score giving you 110 points for this grade.


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Overview  (calendar of dates for homework and tests)




Aug. 20

Aug. 22

Aug. 24
CH 0-5

Aug. 27
CH 0-6

Aug. 29

Aug. 31
CH 3-1

Labor Day

Sept. 5
CH 3-2

Sept. 7
Test #1

Sept. 10
CH 2-1

Sept. 12

Sept. 14
CH 3-3

Sept. 17

Sept. 19

Sept. 21
CW 3-4

Sept. 24
CH 3-6

Sept. 26
CH 3-8

Sept. 28
Test #2

Oct. 1

Oct. 3

Oct. 5
CH 4-1

Oct. 8
CH 4-2

Oct. 10

Oct. 12
CH 4-3


Fall Break


Oct. 22

Oct. 24

Oct. 26
Test #3

Oct. 29

Oct. 31

Nov. 2
CH 4-4

Nov. 5

Nov. 7

Nov. 9
CH 4-5

Nov. 12

Nov. 14

Nov. 16
Test #4

Nov. 19

Nov. 21


Nov. 26

Nov. 28

Nov. 30
CH 4-6

Dec. 3

Dec. 5
CH 4-7

Dec. 7
Test #5




return to PHYS 251 outline