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]

Re: impulse/momentum



I take your point that the reaction of Earth is unmeasurable. But to
prefer that we tell our impressionable young charges that Newton's
third law applies only when neither mass is too large is, in my
opinion, to greatly sully the concept of universal physical law and
to beg the question, "How large is too large?"

John is quite right here. Recall the silly debates we have when we talk
about the ice skater pushing off from a wall. The Earth _does_ move!



Jim Green
mailto:JMGreen@sisna.com
http://users.sisna.com/jmgreen