A ball is dropped from rest from a height h. Neglecting air resistance and taking the acceleration due to gravity to be g, calculate how ling it takes to hit the floor in terms of g and h.

so i set up two equations of motion.

there is not motion in the x direction so

so integrating twice i get two equations

not sure where to go from here, any help appreciated, how do i work out the constants on integration ? I know the ball is dropped from rest, so one of the constants will be 0?