ESS229
Prof. Jin-Yi Yu
Apparent Gravity (g) and Geopotential (Φ)
•An object at rest on earth’s surface experiences both the gravitational force (g*) and a centrifugal force (-Ω2R).
•As a result, these two forces together result in an “apparent gravity” force (g):
•True gravity (g) is perpendicular to a sphere, but the apparent gravity (g*) is perpendicular to earth’s surface.
•Geopotential is the work required to raised a unit mass to height z from mean sea level:
and