For some time now I've maintained textbook errata lists on the net for
students reference. These consist pretty much of calculation errors in
problem solutions, and most of them are submitted by others. I don't
aspire to argue about anything controversial on the lists, just provide
reference to pretty clear errors. Which brings me to the submission
below. I can't even find this in my own copy - which admittedly is
about a decade old. I'm curious some of you would make of this:
*************
On the webpage about errata in Resnick and Halliday, I would like
to
point out that the objection to their proof of Conservation of Angular
Momentum using Newton's third law is invalid. The torques produced by
equal and opposite forces are indeed equal and opposite about any origin
given only that the forces act along the line joining the two particles.
i.e. We have to use Newton's third law in the 'Strong Form'.
And the proferred counterexample is not valid either - Newton's
third
law talks of forces of interaction between two material particles only.
Newton's laws of dynamics do not talk of specific interactions such as
coulombic or gravitainal interactions. Forces arising due to the loss of
energy in the form of radiation are not referred to in Newton's laws. So
the counter example, though correct in itself, does not disprove either
Newton's laws or Resnick and Halliday's proof of conservation of angular
momentum.