Re: On the muliplication of negative numbers

On Jul 28, 4:35 pm, The TimeLord <math-n-physics-...@xxxxxxx> wrote:
Am Sun, 27 Jul 2008 14:18:06 -0700 schrieb Uncle Ben <b...@xxxxxxxxxxx> in
5277af6b-2456-4669-bec1-24e62a6f1...@xxxxxxxxxxxxxxxxxxxxxxxxxxxx:

It might seem strange to consider this plebian topic in a newsgroup
[...]
Negative numbers pose no problem in addition and subtraction.  And
multiplication of a negative number by a positive integer is quickly
understood as repeated addition.  But multiplication of two negative
integers is not so quickly dismissed as a problem.  I admit that I

[...]

The way I usually explain it is as follows. We know from physics that
under constant force, the work done by an object is F*x where x is the
distance travelled. So lay down a positive direction. If the force is in
the same direction as the distance travelled, you get positive work,
whether F>0 and x>0 or F<0 and x<0. The positive work just indicates the
force and distance are in the same direction. If the two are in opposite
directions then you end up with negative work. The bottom line is that
the work, which translates into energy, is independent of which direction
you chose as positive to begin with. So W=F*x is a law which is
independent of the observer, which is nice for formulating natural laws
mathematically.

Usually people buy that.

Interesting.

It works for a physicist, but I am aiming for younger readers.


--
// The TimeLord says:
// Pogo 2.0 = We have met the aliens, and they are us!

.

Relevant Pages

  • Re: On the muliplication of negative numbers
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  • Re: On the muliplication of negative numbers
    ... relativity, But, believe it or not, a controversy has arisen between ... multiplication of a negative number by a positive integer is quickly ... understood as repeated addition. ... strongly suggests), or the standard root sign, then you write ...
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