Final answer:
The furthest below the top-most surface that supports can be placed for a hoop supporting fluid is anywhere below the top surface, ensuring stability and weight distribution. Structures must support the weight exerted by gravity, and in the context of a basketball subject to gravity, the net external force would be below horizontal.
Step-by-step explanation:
To address the question regarding the positioning of supports for the main hoop, we need to understand the principles of statics and the distribution of forces. Assuming we are dealing with a structure designed to hold fluids, the design must account for the fluid weight which the bottom surface exhaustively supports, as stated in the reference figures. Vertical sides provide no upward force due to their inability to sustain shearing forces, indicating that all vertical support must come from below.
In the context of a container or a hoop structure, if gravity is considered, all the supported weight is due to the gravitational pull on the contained fluid. Hence, supports can be positioned anywhere below the top-most surface, as long as they ensure stability and bearing of the entire weight below this point. For a basketball subjected to gravity, the net external force, when unopposed by other forces, would point below horizontal due to gravity.