“If the Earth is rotating, why when we throw a rock upward, it would fall to the original location?” The explanation is that the rock maintains the momentum before it is thrown. Before it is thrown, the rock has the same velocity as the surface of the Earth, it does not suddenly lose its momentum after being thrown, and there’s nothing exerting a force to alter its trajectory.
We usually use the moving vehicle analogy to illustrate this. If we throw the rock upward inside a moving vehicle, it would also fall to the original location, despite the fact that the vehicle is moving.
Flat-Earthers reject the analogy. Their usual excuse is that the atmosphere is not separated from space, and the rock is thrown “inside” the vehicle, separated by the body of the vehicle from the outside. They offer the analogy of being on the top of a moving vehicle as the correct analogy. They are wrong.
The atmosphere is part of the Earth. It has the same rotating motion as the rest of the Earth. If it were not, we would feel a 1656 km/h (1030 mph) wind near the equator. We never experienced such wind, and thus, we can conclude that the atmosphere is practically not in motion relative to the surface.
An observer at the top of a vehicle moving at 60 km/h (37 mph) would feel a wind with the same speed of 60 km/h (37 mph) toward the back of the vehicle. If we throw a rock upward in such condition, the wind will exert a mechanical force and cause it to move toward the back of the vehicle; not unlike a fan that blows a sheet of paper away from it.
This case is one of the many cases where flat-Earthers failed to control unrelated variable that has no relation to the experiment. And worse, sometimes they not only failed to control such variable but they deliberately introduce it to the experiment.
The “on the top of a moving vehicle” analogy is invalid because it has the wind factor that affects the experiment, and does not exist in the situation the analogy is being applied to.