Question

A stone falls from a building and reaches the ground 2.5 seconds later. How high is the building ? (g =9.8 m/s²)

Answer 1

Given: u (initial velocity) = 0 m/s

a (acceleration due to gravity i.e. g) = 9.8m/s²

t (time) = 2.5 sec

Formula: S = ut +1/2 gt²

= 0 ×2.5 + ½ × 9.8× 2.5× 2.5

= ½ ×9.8 ×2.5× 2.5

= `61.25/2`

= 30.625 m