Answer: 19.6 m
Explanation:
A rock is dropped from the cliff. It means its initial velocity, u = 0 m/s
It free falls under gravity.
Using the second equation of motion:
s = u t + 0.5 a t²
s = height of cliff
u = initial velocity = 0
t = time of fall = 2.0 s
a = g = acceleration due to gravity = 9.8 m/s²
⇒ s = 0 + 0.5 × 9.8 m/s² × (2.0 s)² = 19.6 m
