If it is hovering, you are being told that vi = 0 [The initial downward velocity is 0]
Givens
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vi = 0
a =9.81 m/s
d = 200 m
Find
====
t
Formula
=======
d = vi * t + 1/2a*t^2
Substitution and Work
================
200 = 0 + (1/2)* 9.81 * t^2
200 * 2 = a*t^2
400 = 9.81 * t^2
200 / 9.81 = t^2
20.39 = t^2
t = sqrt (20.39)
t = 4.52 seconds.
