Question

A rock at rest falls off a tall cliff and hits the valley below after 3.5s. What is the rocks velocity as it hits the ground

Answer 1

t = 3.5 secs

Velocity (v) = g * t = 10 m/s^2 * 3.5 sec = 35 m/s

Answer 2

v = u + at
u=0(rest) ; a=gravitational acc(g)=10
v = 0 + 10(3.5) = 35m/s