Question

You accidently throw your car keys horizontally at 8.0 m/s form a cliff 64m high how far is the keys from the kliff

Answer 1

First, find how long they fell, t,
from distance y = (1/2) g t^2.
64m = 0.5 (10m/s^2) t^2.
t = sqrt[64/5)

Next use t (in sec) to find horizontal distance
x=v t, x=(6 m/s) t

There you are.