I have read this question:
My question is different, because that question does not talk about (only the comments) the fact (that I think matters most) that the Earth's rotation (or the person on the surface) is an accelerated frame. The answers (and comments) to that question talk about comparing the feeling to traveling in a ship with constant speed. That is an inertial frame of reference. My question is about why we do not feel being accelerated in the (non-inertial) frame of reference on the surface of Earth rotating?
Where Wouter says:
I know it's very late in the game for this question, but this is partly a biology question. We don't feel the rotation of the earth because our brains are biased, they evolved that way. It's not useful to experience/be aware of this rotation day by day, in the same way it isn't useful to be aware of gravity.
And where Dan says
Because the rotation of the earth is very smooth and doesn't change, the centripetal acceleration we feel is very nearly constant. This means that the (small) centrifugal force from the rotation gets added to gravity to make up the "background force" we don't notice.
Where it says:
So why can't we all feel it? The answer lies in the nature of Earth's movement. Think of being on an aeroplane when it's smoothly travelling at a constant speed and constant altitude. You've unbuckled your seatbelt to go on a walk down the aisle, but you can't feel the movement of the plane. The reason is simple: you, the plane, and everything else inside it is travelling at the same speed. In order to perceive the movement of the plane, you have to glance at the clouds outside.
So this one is saying that we don't feel it because like in an aeroplane, we move with the plane, so this is our inertial frame of reference.
But the plane is moving with a constant speed in this example. I believe it is not OK to compare it to the rotation of the Earth, because the Earth's spin is an angular momentum, and though the angular momentum itself is constant, this is considered acceleration, so any point (or person) on the surface of the Earth is accelerating.
Now one answer says that we do not feel it because our brain is used to the acceleration. The other one says it is because the angular momentum of the Earth is constant.
Which one is right? I do not understand, is it because there is no change in the acceleration, or is it because our brain is used to it, or is it because the centripetal force is so little compared to gravity?
Why do we really not feel the angular momentum of the Earth, is it because there is no change in the acceleration, or is it because our brain is used to it, or is it because the centripetal force is so little compared to gravity?
Even if the acceleration is not changing, the person on the surface is in a non-inertial reference frame. How can't we feel this acceleration? The equivalence principle only goes for gravity and the acceleration and as per GR we would not know the difference between them. But we would still feel it.