Question

A rock tumbles straight down from a cliff, its moving at 20 m/s when it hits. What is the height of the cliff? The mass of the rock is 8 kg.
a) 2.5 m
b) 400 m
C) 20.4 m
d) 160 m

Answer 1

What's the time?

Answer 2

v = g t
20 = 9.81 t
t =2.03 seconds

h = (1/2) g t^2
h = 4.9 (2.03)^2
h = 20.4 meters

Answer 3

yolo