Fall 2000 Physics 272
Study Suggestions and Problem Solving
- Keep good notes. Use the text to fill in lecture material. The
act of writing material down helps to cement the ideas in your brain.
- You must work problems; this is how you learn physics. Think of
it as working out, just like pumping iron (but a lot less
repetitive!). As in learning a language, one `gets' the concepts by
speaking and not just by listening. You cannot learn to surf
by watching videos, and one cannot learn physics without thinking
the concepts through. There is more to it even than just becoming
facile with the specific concepts: physics is a way of thinking
about and approaching the world. One learns this through a kind of
apprenticeship approach, familiar to many disciplines.
- Do not get bogged down in units. Keeping track of units in
solving problems is very useful, and dimensional analysis [figuring
out what dimensions (say, length/time) the answer should have, and
thus something about the form of the equation which will give that
answer] is a very powerful tool. But, conversion constants and the
like can always be looked up. Still, one needs a few benchmark
numbers at one's fingertips in order to have a feel for when one has
the answer roughly right or off by some huge factor.
- There are many many equations. Don't try to remember all of
them. Learn a few of the fundamental equations. You may want to
keep a summary sheet of these, which will be useful at test time for
your "cheat sheet".
- Study a little every day. Set aside some definite hours, and do
not focus upon how much you need to get done. Just work
diligently for the allocated time. You will always find that it
takes longer to read the book, do the problems and such, than you
thought it would. Don't get too far behind and allocate more study
time after a week or so if you are slipping.
- Physics is a quantitative science, which means that things can
be calculated numerically. Sometimes these calculated results can
even be checked experimentally to very high precision. The way that
we learn physics is by problem solving. Problem solving is an art
which must be mastered in order to do well in the course. This
skill (quantitative reasoning) will also be useful in many other
fields, from engineering to finance to making sensible decisions as
a consumer and citizen of an increasingly technically complex world.
- We teach problem solving in several ways:
- Class Examples: We will work many examples in class. Follow
this `style'.
- Book and Study Guide Examples: Many examples are provided to
aid the student. See the User's Guide in the front of the text (pages
xxvii-xxxi) to see how the book provides insights and strategies to help you
become good problem solvers.
- Homework: This is your chance to practice what you have
learned. Lot's of homework is given, and it is collected and graded every
class and is weighted in your grade. You can probably copy someone
else's work, which we greatly discourage, but you will ultimately be
the loser if you do so. It is not a bad idea to work together as a
team on the homework, if you wish. Often peers can learn much from
each other. However, there is the danger of becoming dependent on
whichever team member is quickest at problem solving.
- Homework instructions:
- Use 8 1/2" x 11" notebook paper. Keep your old homework in
a binder for study purposes (and who knows you may be a grader later
yourself!). Use only one side of the paper.
- Staple your sheets together and fold them in half the long
way. Put your name, social security number, and problem set number
on the top right side of the first sheet (inside) and on the top
right side of last sheet (outside).
- Neatness does count. The grader can't give partial credit
if he/she can not read your paper. Sloppy work often reflects sloppy
thinking.
- Use a reasonable number of significant figures for your numerical
answers. You will be graded down for ridiculous accuracy. Writing
down an answer as 3.999999999 when the number is really 4 for all
practical purposes is not just lazy, it shows a lack of
understanding that one does only measure things usually to a few
decimal places. Indeed acquiring some sense about how much accuracy
is need is important to the physics, and vital to engineering and
many other practical matters.
- If you do not see how to do the job intuitively, then try to
follow the recipe below when doing problems:
- Paraphrase the problem (briefly): write it out in your own terms.
- Draw a diagram and label it. Diagrams are often crucial; problems
without diagrams will usually be graded down.
- Write down what is given and what to find.
- Write down the relevant formulae. Use symbols at this stage,
except for constants.
- Reorganize the formulae to get the desired unknown on
the left of the equal sign and the known quantities on the right.
- Rewrite the equation with numbers and units inserted.
- Write the solution with units and put a box around it.
Be sure that you use vectors and scalars properly when writing your
final results.
last revised 14 August 2000, jgl.