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The following was written by Professor Kathie E. Newman in the Summer of 2004.
Exercises
and Problems
Exericises
are generally easier than problems. Start by warming up with the
exercises. If this gives you difficulty, then start doing all of
the odd exercises.
The
exercises and problems chosen are mostly those solved in previous
year's classes.
Pay
particular attention to the * problems. These are "classics"
-- which are ones that physicists tend to gravitate to when designing
an exam. Yes, it is a judgement call labeling a problem a "classic."
I haven't worked all of the problems, so I'm sure that my list (which
had input from last year's class) isn't complete. And, remember
that I'm just one physicist, and the exam is designed by a committee.
The
** problems are ones that we judged to be particularly tough. Occasionally
one of these has appeared on a qualifier.
Problem-Solving
Psychology
Let's
start by acknowledging, there's a ton of problems, exercises, and
worked examples in the book. Any one of them can become a qualifier
exam problem. You will not be able to do all possible problems.
So, your task is instead to become confident that you can work a
certain percentage of possible problems, allowing 15 to 30 minutes
per problem. You want to maximize this percentage, but it is unrealistic
to think that your percentage will be 100.
Think
of this like physical exercise. You are in training to run a marathon.
Your goal is to finish the marathon in decent shape. You just want
to cross the finish line, it doesn't matter if you are first or
not.
An
unlike most marathons, you have a choice which way you run. You
will choose which 8 of 10 problems you solve. Just as you should
assess the steepness of a hill before you run up it, you should
learn to assess the difficulty of problems.
As
runners do, give yourself continual internal positive messages.
Try a mantra, "I am physicist and I am strong. With time, I
can solve the world!" Don't use negatives in your internal
messages -- eliminate the not's, don'ts, can'ts from your thoughts
(yes, those two phrases were phrased in the negative) -- instead
learn to phrase in the positive and tell yourself that you can solve
the problem, you can understand the physics.
Be
very honest with yourself. Listen carefully. When you feel uncomfortable
with something, try to find out why! There's usually a point of
physics that you are missing; you need to figure out what. Perhaps
you never studied some of this material previously, so allow yourself
more time to learn it properly. Perhaps you did study previously,
but you find you really didn't understand it. Learn to tell when
you have mastery.
Here's
a trick. Pick an imaginary audience -- perhaps your mother, your
little sister or brother or perhaps a freshman -- and now imagine
teaching this area of physics to that person. What's important?
What are the primary concepts? We use a variation of this trick
when working problems together in groups or at the blackboard. Remember,
being able to teach requires a higher-level mastery of the physics.
And, if you are a teaching assistant, you will really want to have
this mastery.
Try
to avoid paging back in the text in order to find answers. You can't
do this in a test, so form the habit now of challenging yourself
to work without crutches. Think what crutches you have -- the book,
the odd answers, the knowledge that a particular problem comes from
a particular chapter, and the equation sheet. You are allowed one
crutch in the exam -- the equation sheet -- so, try working as much
as possible using just the equation sheet.
It
does not hurt to do more problems or exercises than assigned, up
to a certain point. Thinking again of the long-distance race metaphor,
you want to train just to the point where you can handle the race
easily. You don't want to start exhausted. Your goal is to learn
to identify the point where you have mastery of the material.
Finally,
remember that physicists are like athletes in another way. I never
was enough of an athlete to enjoy the process of training. But,
as physicists, I do enjoy the training, that is, the process of
thinking about how physics explains the world. Halliday, Resnick,
and Krane is well written; it can be fun to go through problems.
Enjoy this time and chance to be a master, to be an athlete at the
top of his/her form.
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