Question

A body is released from a great height falls freely towards the earth. Another body is released from the same height exactly a second latter. Then the separation between two bodies, $2\,s$ after the release of the second body is, nearly

• A. 15 m
• B. 20 m
• C. 25 m
• D. 30 m

Answer 1

Answer: (C)

25 m

Answer 2

$s=u t+\frac{1}{2} a t^{2}$
For 1st body $u =0$ and a $= g$ (freely falling body)
Distance covered in $2\, s$
$s_{1}=0+\frac{1}{2} g(2)^{2}$
For 2 nd body Distance covered in $2\, s$
$s_{2}=0+\frac{1}{2} g(3)^{2}$
hence $s_{2}-s_{1}=\frac{1}{2} g\left[(3)^{2}-(2)^{2}\right]$
$=\frac{1}{2} g[9-4]$
$=25\, m$