Next message: George Huxtable: "Re: Navigating Around Hills and Dips in the Ocean"
George says: "It's possible to go from one value of g to another, always
following
> an equipotential path, and there will be changes in elevation above
> the Earth's centre along that path, but being an equipotential path,
> there will be no work done against gravity. None at all. In fact, this
> is exactly what
> happens when a ship travels from one latitude to another and from one
> value
> of g to another, over the oceans."
Can we have further explanation of this? My brain tells me that moving
along an isobar (to make a simple analogy) can't move you to an area of
higher pressure. Are equipotential shells not analogous to isobars?
Keith Williams
