Question

If a stone with an original velocity of 0 is falling from a ledge and takes 8 seconds to hit the ground, what is the final velocity of the stone? A. 39.2 m/s B. 42.6 m/s C. 78.4 m/s D. 156.8 m/s

Answer 1

your answer is C. 78.4 m/s

i just took the test

Answer 2

Getting the final velocity of a free fall, we need to use this formula:
vf = g * t
where
g = 9.8 m/s^2
t = time

From the problem given, the final velocity of the stone is
vf = g * t
vf = 9.8 m/s^2 * 8 s
vf = 78.4 m/s

So the correct answer is letter C. 78.4 m/s