[Phys-l] Pound mass or weight?

["John Clement" <clement@hal-pc.org>]

As I recall there was a pound mass, and a pound force defined at one time.
Currently engineers still are taught the slug mass and pound force.  The
"common" definitions are hopelessly at odds with each other, and confused.
Even the Natl Bureau of STD at least in one place equates mass with weight.

As to confusion caused by authors, some should know better.  An
astrophysicist and respected author wrote a hopelessly wrong explanation of
Newton's third law for the World Book Encyclopedia.  In it he uses motion to
explain how action = reaction, and never mentions force.  So of course when
he mentions a ball bouncing off of a wall, the action obviously does not
equal the reaction.  Now if he had used momentum, he would have been
correct.  Also he repeats the idea that negative acceleration is always
slowing down.  This is a common interpretation which is a resistant
misconception.  Do our own people have to try to be so popular that they
have to repeat these misconceptions, and imbed them deeper in student
psyches?

If anyone knows the man perhaps they could communicate with him about the
problem.  I sent him an E-mail, but he does not know who I am and assumes I
am a kook, which may be true.  Anyone who wishes to write physics accounts
should read a bit of the research about misconceptions and how language
should be used to promote clear communication about science.  The world book
is a major resource for students and families.  The Wikipedia is accurate,
but hopelessly difficult for students who are not engineers or physicists.

There is a website www.brainpop.com that is presenting lessons on many
topics including science.  They should be ashamed of the outrageous
misconceptions that they are promoting in both the movies and the quizzes
they distribute.  It is used by a number of teachers and districts have
bought access to it.  Don't they have physicists parsing their material?
The answer is rhetorical because they obviously don't

John M. Clement
Houston, TX


> Well, Wiki also disagrees with you
>
> http://en.wikipedia.org/wiki/Pound-force
>
> Bob
>
> On Nov 4, 2008, at 10:43 PM, Bernard Cleyet wrote:
>
> > I, too, went thru life (about > 50 years) thinking the pound was a
> > unit of force.  It is not, as pointed out by JD recently.
> >
> > https://carnot.physics.buffalo.edu/archives/1999/10_1999/msg00645.html
> >
> > "For what it's worth" Wiki. agrees w/ me also:
> >
> > http://en.wikipedia.org/wiki/Pound-mass
> >
> > bc, disabused.
> >
> >
> >
> > On 2008, Nov 04, , at 10:25, Rick Tarara wrote:
> >
> > >  The technically
> > > incorrect 2.2 lbs = 1 kg (formally the weight of 1 kg is 2.2 lbs)
> > > works
> > > fine.