🚀 go-pugleaf

Donal Simanek wrote in response to a posting of mine
>
>There was an article in Physics Today a
>couple of years ago making this same point,
>(that it is unnnecessary to speak about relativistic
>mass) and an article by someone else taking the
>opposite side.

Don,

   Thanks for your kind response and thanks
for the refereence. When I posted my piece, I
knew that I had somewhere seen an article by someone
who was in position to speak authoratatively who spoke
out against the use of relativistic mass - but I couldn't
find the reference. Goldstein, in his graduate level
mechanics book does imply this, but his statement is
not the emphatic one I remembered. And Resnick, in his
book on relativity, does refer to relativistic mass without
any qualms. I must have been thinking about the Physics Today
article to which you refer,

Ed Schweber
e-mail: EdSchweb@ix.netcom.com

There's at least one college textbook in 'Modern
>Physics' which avoids use of relativistic mass (Burns, I think. I
*must*
>get near my library soon and supply some of these references.) I know
>these were instrumental in getting me to think about the matter, and
to
>revise my class notes to eliminate relativistic mass entirely. It
wasn't
>difficult. What's difficult is to explain to students who read other
books
>why we aren't using the idea in class. They seem to think it of great
>importance. So I ask: "How do you propose to measure the relativistic
mass
>of a moving object directly?"  Any method they come up with is a
measure
>of energy, or a measure of momentum, *not* a direct measure of mass of
a
>moving body. Then some of them get the idea.
>
>This is another example of how we teachers, and textbook writers,
>thoughlessly perpetuate modes of presentation which are wrong,
misleading,
>or unnecessary. I still catch myself accidentally speaking of 'current
>flow', or using the word 'voltage' or 'amperage' instead of
'potential' or
>'current' and then mentally kicking myself for mental laziness. I do
think
>textbook writers are the most to blame, for they have the luxury of
time
>to think about what they say, and have proofreaders and editors and
>reviewers who ought to catch these things, or at least question them.
Too
>many of them just copy each other, including the mistakes. Why doesn't
>someone write better textbooks? They have. I've seen excellent
>textbooks which departed from the pattern, and were not simply clones
of
>the others, which died in the marketplace because they were
'different'
>enough that few teachers dared adopt them. Old habits die hard.
>
>        -- Donald
>