This is a freefall movement, which is unformly accelerated.
Then the equation that rules the relation of distance and time is:
d = Vo*t + at^2/2
Where Vo, is the initial velocity =0
a = acceleration = 1.62 m/s^2
t = time
d= distance
Then, d = a*t^2/2 ==> t = sqrt(2d/a) = sqrt (2*1.2m/1.62m/s^2) = 1.2 sec.