Question

a stone dropped from the roof of a building takes 4s to reach the ground.calculate the height of the building.

Answer 1

T = root over 2 h /g

H =T^2 g/2

H =80 m

Answer 2

$\bf{\underline{\underline{Answer:}}}$

$\bold{\pink{\green {\sf{\therefore\:Height\:=\:78.4\:m}}}}$

$\bf{\underline {Given:}}$

$⟹Initial \:velocity\: of \:object, \:u\: =\: 0$

$⟹Acceleration \:due\: to \:gravity, \:g = 9.8 m {s}^{-2}$

$⟹Time, \:t = 4\: s$

$\bf{\underline {To\:Find:}}$

$⟹ The\: height\: of \:building = ?$

$\bf{\underline{\underline{Step\: by\: step \:explanation:}}}$

We know that,

${h} = ut + \dfrac{1}{2}gt^2$

Substituting the values, we get

$h = \dfrac{1}{2}×9.8×16 = 78.4m$

$\bf{ Thus, \:the \:height \:of \:building\: is\: 78.4 \:m}$