Question

A body falls freely under gravity from rest and reaches the ground in time $t$. Write expression for the height fallen by the body.

• A. $H=\frac{1}{2}$ $g{t}^2$
• B. $H=ut+\frac{1}{2}$ $g{t}^2$
• C. $H=\frac{1}{2}$ $gt$
• D. $H=ut-\frac{1}{2}$ $g{t}^2$

Answer 1

The correct option is A $H=\frac{1}{2}$ $g{t}^2$

We know that second equation of motion is given by
$S=ut+\frac{1}{2}g{t}^2$
where $\text{S = distance, u = initial velocity = 0 , t = time , g = acc. due to gravity}$
$\Rightarrow S=\frac{1}{2}g{t}^2$
Since, $u=0$