Arock is dropped downward from the top of a cliff. if the rock hits the ground after 2.0 s, what’s the height of the cliff?

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

d₁ = displacement of tern from arctic to antarctic = 11000 miles

d₂ = displacement of tern from antarctic to arctic =   - 11000 miles

d = total displacement for the journey

total displacement for the journey is given as

d = d₁ + d₂

d = 11000 + (-11000)

d = 0 miles

t₁ = time of travel from arctic to antarctic = 3 months = 3 x 30 days = 90 days

t₂ = time of travel from antarctic to arctic = 3 months = 3 x 30 days = 90 days

t = total time of travel

total time of travel is given as

t = t₁ + t₂

t = 90 + 90

t = 180 days

average velocity is given as

average velocity = total displacement/ total time

v = d/t

v = 0/180

v = 0 miles/day