Hello, I have two question about the force of buoyancy.

1. When an object floats exactly at the surface of a liquid, is the buoyancy force 0? It is a bit confusing to me because according to the buoyancy force equation, no volume of the object is submerged in that case so Fb should be 0, but then if there is no force upwards (Fb), what is the force that is counteracting the force of gravity so that this object is not sinking?

2. I know that buoyancy force doesn’t change for a fully submerged object no longer where it moves as long as it is still fully submerged. When a fully submerged object moves from the middle of the water to resting at the bottom surface, how does the buoyancy force stay the same if there is an additional force now, which is the normal force and the force of gravity didn’t change?

Thank you!