A stone is projected vertically upwards from the top of a tower with speed 14 m s-1. It passes a point PPP, which is 6 m above the point of projection, twice. The stone is modelled as a particle moving freely under gravity. Use g=9.8 m s−2g=9.8\text{ m s}^{-2}g=9.8 m s−2.
Find the time between the two occasions on which the stone passes PPP. Give your answer to 3 significant figures.