Question

A body is released from the top of the tower $H$ metre high. It takes $t$ second to reach the ground. Where is the body after $t/2$ second of release ?

• A. at $3H/4$ metre from the ground
• B. at $H/2$ metre from the ground
• C. at $H/6$ metre from the ground
• D. at $H/4$ metre from the ground

Answer 1

The correct option is A at $3H/4$ metre from the ground

Applying: $S=ut+\frac{1}{2}g{t}^2$ for the first case

$H=\frac{1}{2}g{t}^2$ .......(i)

Let $S_1$ be the distance after $t/2$ secs.

$S_1=\frac{1}{2}g{\left(\frac{t}{2}\right)}^2$

$\Rightarrow S_1=\frac{1}{8}g{t}^2=\frac{1}{4}H$ .......(ii)

Hence, height from the ground is $H-\frac{H}{4}=\frac{3H}{4}$