At which position, a or b, is the potential energy of the
swing the greatest?
as the swing moves from point b to point a, which form
of energy is increasing, kinetic or potential?

i would think it's food chain

force tends to be low and long diustance masses are high

because if the tool that you are using is not balanced it there would be false mass.

no. bullets are macro objects. wave nature is for light waves, extremely tiny particles. if a light particle was the size of your finger, the bullet would be the size of the universe. so basically, that huge difference in size makes the wave nature of matter insignificant.