if a rock is dropped from the top of a 200 ft building, solve for the time it takes for it to hit the ground. (when h=0)

Question

hint-initial velocity when dropped is 0

Answer 1

in non-metric units

h = -16t^2 + 0t + 200 , where t is in seconds and h is in feet

so when it hits the ground , h = 0
so 0 = -16t^2 + 200
16t^2 = 200
t = √(200/16) = 10√2/4
= 5√2/2 or appr 3.54 seconds