Question

A stone is dropped from a cliff. Calculate it's speed after it has fallen 80m. (Take g=10 m/s²)

Answer 1

1/2mv2=mgh

1/2v2=80*10

v2=1600

v=40

40m/s

Answer 2

$\huge\mathfrak\purple{Answer :}$

Given,
•Initial Velocity = 0 [ stone is being Dropped ]
•Distance [ h ] = 80m
•Gravitational Acceleration = 10ms^-2

From Third Equation of Motion
v^2 = u^2 + 2as
v^2 = 0 + 2*10*80
v^2 = 1600
v = √1600 = 40

Therefore, The Velocity of the Stone after it has fallen 80m is 40ms^-1.

$\huge\mathfrak{Hope\:it\:Helps}$