the gravity at the poles and equator is the same
I wanted to write “almost the same” but didn’t want to confuse more.
The earth is slightly squished, right? So yes, gravity would be slightly stronger at the poles, but look at this
Distances from points on the surface to the center range from 6,353 km to 6,384 km
31km in it. That won’t have any noticeable effect, especially over the difference in reaction force caused by the earth spin.
Yes but you’ve still got your forces backward. Centrepetal force has no effect on people standing at the equator (unless they are tied round the ankles by a piece of rope connected to the centre of the earth)
Centrifugal force due to their angular momentum decreases the apparent gravity