Make your example of a parabola in real life (Bouncing ball) the subject of your post and then tell us in your own words about your parabolic find (at least 250 words). Do not just make this up off the top of your head. The St Louis Arch, for example, is NOT a parabola - it is an inverted catenary. Please cite a source confirming that your example is, indeed, parabolic and not some other more exotic curve.