Chronology | Current Month | Current Thread | Current Date |
[Year List] [Month List (current year)] | [Date Index] [Thread Index] | [Thread Prev] [Thread Next] | [Date Prev] [Date Next] |
Many authors say that N's 3rd law pair forces do not cancel because theyYou can add any two vector having same magnitude and opposite direction
are acting on different (i.e. opposite) objects. Randy Knight, in his new
PER-based textbook, says, in his discussion of conservation of momentum,
that
\vec{F}_{k on j} + \vec{F}_{j on k} = \vec{0}. Is the discrepancy between
these two statements real or imagined? Would you tell your students one or
both or neither of these statements? I have told students that we don't
even add forces on different objects together; should I not have? What's
the best pedagogical approach to this? Further comments?
Thanks in advance,
Larry