Question

a stone is dropped from a bridge and it reaches to the ground in 4 second so what is the height of the bridge

Answer 1

Assuming that the bridge exists on the earth

So, g = 9.8m/s^2

Let s be the height,

By Formula

$s = \frac{1}{2} \times g \times {t}^{2}$

Substituting the values.


$s = \frac{1}{2} \times 9.8 \times {4}^{2}$
Simple mathematical operations


$s = \frac{1}{2} \times 9.8 \times 16$

$s = 9.8 \times 8$

let's multiply


s=78.4metre


The height of the bridge is 78.4 metre