To solve this problem, we will use the equation of motion:
v = u + at
where:
v is the final velocity = 117.72 m/sec
u is the initial velocity = zero (body starts falling from rest)
a is the acceleration of the body which is equivalent to acceleration due to gravity = 9.8 m/sec^2
t is the time that we want to calculate
Substitute with the givens in the above equation to get the time as follows:
v = u + at
117.72 = 0 + 9.8t
117.72 = 9.8t
t = 117.72 / 9.8
t = 12.0122 seconds