>From:         "Karl F. Bloss" <bloss@enter.net>
>
> > based on the original poster's assumption that the water pump has to work
> > relatively hard to pump coolant uphill, would it do less real work if
> the van
> > were constantly driven downhill?
>
>Forget differential equations.  If it's a closed non-leaking system, it
>doesn't
>matter how the van is facing, the waterpump is only overcoming the frictional
>losses in the system, not pumping up or down.  I.e. the more piping, the more
>friction, the more the pump has to work.
>
>Uphill and downhill don't matter because the starting and stopping point for
>the fluid is the same.  If the van is facing downhill, for every unit mass of
>coolant that's going downhill, another unit mass is going uphill and vice
>versa
>if it's pointing uphill.
>
>-Karl

OK, I understand how this applies (& makes sense) when driving North, or
South, but what about East <-> West???

Austin (save for Friday...)