Why does the buoyant force on a submerged object not act sideways?

Answer 1

The origin of buoyant force is earth's gravitational pull, which is basically "vertical" at a point on the earth's surface. You don't possibly have another object to the side, so heavy that it can affect earth's gravitational pull. Buoyancy is the reaction force to explain why an object, which has a finite weight, is floating in water. In deep space where gravity is extremely weak, the object will not experience much buoyancy at all (in deep space, up or down has no meaning either).

Answer 2

Because buoyant force arises out of different pressures at different depths ...

the pressure on the bottom of a submerged object is greater than the pressure

on top of it. But there is no difference between the pressure on the object's

left side compared to its right side, at the same depth, so there's no net

horizontal component of force on it.

Answer 3

It does. But every sideways force on one side of the object is balanced by an

opposite sideways force on the other side of the object, so the net horizontal

force is zero. You don't have that balance among the vertical forces, because

the pressure varies with depth, so the forces on the top and bottom can't be

equal, and plus there's also the force of gravity thrown in there.