It's a two part question, but it basically says this:
a bolt drops from an elevator 9.0 ft from the ground, at what time does it hit the ground?
x = x0 + vx0t + 1/2ax(t^2)
The Attempt at a Solution
since it's a free fall question and we're starting from above ground:
0 = 9.0ft - 16ft/s^2 (t^2)
-9.0/-16 = t^2
t = 0.75 seconds.
But the book says that t = 0.71 seconds..