Larry C. answered 11/30/18
Computer Science and Mathematics professional
The general equation that would apply here is d = vi*t + 0.5at2 where d is the distance traveled, vi is the initial velocity, t is the time and a is the acceleration. In this case, we are dropping the container from rest, so vi is zero, which simplifies the equation to d = 0.5at2. Since we want to know t, this becomes t = sqrt(d/0.5a) or sqrt(2d/a).
We know d is 30 feet. a is the acceleration due to gravity, which is roughly 32 feet/sec2, so the final equation is t = sqrt(64/32) = sqrt(2) = approx 1.41 seconds