NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Navigating Around Hills and Dips in the Ocean
From: Bill Noyce
Date: 2003 Aug 19, 15:18 -0400
From: Bill Noyce
Date: 2003 Aug 19, 15:18 -0400
Here's another analogy about the equipotential/g situation that might help intuition. Imagine you're walking across a landscape of rolling hills, always keeping the same altitude above sea level. In this case you're walking along a line of equal gravitational potential -- these are called contour lines on a topographical map. As you're walking, or perhaps pushing a soccer ball, you will notice a force to the side that depends on the steepness of the hill where you happen to be. This is the 2-dimensional analog to the strength of gravity, and is represented on the topo map by how close together the contour lines are. You can certainly walk from a place where this force is very weak (the hill is very shallow) to a place where it is strong (the hill is steep) without gaining or losing altitude, and therefore without gaining or losing any potential energy. -- Bill