There are several formulas that describe the distance, speed, and time for
a falling body. The one I use the most happens to be the one that'll be the
most useful to solve this problem:
Distance = 1/2 g t²
We know the distance and we know ' g ', so we can use
this formula to find ' t '.
Distance = (1/2) (gravity) (time)²
(239 m) = (1/2) (3.7 m/s²) (time)²
Divide each side
by 1.85 m/s² : (129 m) / (1.85 m/s²) = (time)²
(129/1.85) sec² = (time)²
Take the square root
of each side: 8.35 sec = time