A ball is dropped from the top of a tall building h=5m about how long does it take for the ball to hit the ground.

D=-5m

a (gravity) = - 9.8m/s^2

vi = 0m/s

t=?

use equation d=vi*t+0.5a*t^2

because vi=0, you can cross out vi*t because anything multiplied by 0 = 0

rearrange the equation to say t^2=d/0.5a

t^2 = - 5/-4.9

t^2=1.02

find the square root ...

final answer: t=1s