A 72.0-kg swimmer jumps into the old swimming hole from a diving board 3.25 m above the water. Use energy conservation to find his speed just he hits the water
(a) If he just holds his nose and drops in,
(b) If he bravely jumps straight up (but just beyond the board) at 2.50 m/s, and
(c) If he manages to jump downward at 250m/s.