Gravity vs Centrifugal Effect

[georgert]

If I have a mass of 80 kg, what would the difference in my weight be at either the North or South Pole and at the equator? It would seem to me that the spin of the earth would induce a centrifugal effect that would counter somewhat earth's gravitational pull at the equator, but not do so at earth's axis of spin.

[arildno]

If I have a mass of 80 kg, what would the difference in my weight be at either the North or South Pole and at the equator? It would seem to me that the spin of the earth would induce a centrifugal effect that would counter somewhat earth's gravitational pull at the equator, but not do so at earth's axis of spin.
That's absolutely correct.
The effects of having an equatorial bulge and flattened poles also contributes to variation of the local value of "g", compared to what you'd get by a strictly spherical shape.
"g" is also slightly dependent upon density variations.


According to Wikipedia, the local values of "g" are as follows:
local gravity, g, increases from 9.789 m·s−2 at the equator to 9.832 m·s−2 at the poles.[1]