scott wrote:
> I think the key point is that most 
> things have a force that acts in the opposite direction of the movement, 

I've always found this to be quite fascinating. Why should that be?

Why is back EMF always in the direction that reduces the EMF? Why does 
friction work in a direction that reduces the effects of friction?

Almost everything one can think of works this way. I only remember 
encountering two or three effects in the last few decades (other than 
economics and some odd quantum stuff, IIRC) that don't damp themselves. 
Unless you get something like thermal runaway, where you have two separate 
effects reinforcing each other that would individually damp each other out.

Funkily enough, if you look at wikipedia under "Negative_mass", there's some 
stuff in there about what happens if mass is negative, with fun observations 
like "negative masses would produce an attractive force on one another, but 
would be repelled because of their negative inertial masses". I.e., the two 
minus signs on the mass cancel out, so two negative masses are attracted to 
each other, *but* they'll move apart, because negative mass moves towards 
the direction you push it from. :-)

</ramble>

-- 
   Darren New, San Diego CA, USA (PST)
   There's no CD like OCD, there's no CD I knoooow!

Post a reply to this message