PROBLEM SET 4 COMMENTS - SPRING 2003

	The material needed to do all of these problems is from
	French, and so the required readings are important.

	4.1:  For starters, if you consult the appropriate part of
          French's text (try the index), the problem is mostly done.
          However, the section "THE ENERGY IN A MECHANICAL WAVE",
          Pages 237-240, was not assigned (the subject will be covered
          in recitation, March 6).

	4.2:  Especially for part (b), you are strongly encouraged to
          read French pages 256-258.  In reading these pages, look
          carefully at the notation (I think he wants a g_1 in
          Equation (8-1), but it's the only "g" of any kind in the
          discussion).  French admits the use of a "subtle but very
          important piece of reasoning."  Part (c) is crucial;  if you
          don't get the expected results, it means that something in
          one of the previous parts is not quite right.

	4.3: It doesn't matter much (besides the presence of a
          not-so-swift figure), but this is B&B 2.5, and you might
          want to refer to that text for notation.  Remember, "p" is
          the "overpressure", the amount by which the pressure differs
          from equilibrium or "atmospheric" pressure.  In the B&B
          text, and in lecture March 5, the atmospheric pressure was
          denoted as p_0, which in the problem is also the
          overpressure at the middle of the pipe.  So, this would mean
          a total pressure of twice atmospheric at the middle of the
          pipe, which could happen, but is unlikely for an open pipe.
          For the purposes of this problem, it doesn't matter.

	4.4:  In about as unsubtle a hint I can give, if you read
          French really carefully, you'll know where to find the
          answers to a very simlar problem.  (The above sentence is
          deliberately vague).