Final answer:
The conservative forces from the given options are gravity and spring force. Friction and air drag are not conservative forces because they dissipate energy instead of conserving it.
Step-by-step explanation:
The question is asking which forces are considered conservative forces. A conservative force is a force with the property that the total work done in moving an object between two points is independent of the taken path. Instead, it only depends on the objects' start and end points in a system. Typically, conservative forces have potential energies associated with them and they conserve mechanical energy within a system.
Given the choices:
These are both examples of conservative forces. Changes in their associated potential energies are predictable based on the positions of the objects involved. On the other hand, static friction, kinetic friction, and air drag are not conservative forces. They dissipate energy in the form of heat or other forms of energy and do not have associated potential energies that are solely dependent on the position of the objects in the same way.
As for the potential energy changes of a diving board, assuming negligible friction, which makes the forces conservative, when a swimmer steps on the board, potential energy is stored in the board as it bends. This energy is at its maximum when the board is maximally bent downward. Just after the diver leaves the board, the potential energy is converted into kinetic energy, which then decreases to zero as the board returns to its equilibrium position.