Question

A body reaches ground in time T when dropped from height h, what is the time taken by the body
if it is dropped from height 2h?
(a) 2T (b)(√2-1) t. (c)√2t. (d)T/√2 ​

Answer 1

Answer:

(c)

Explanation:

here displacement (S) from the ground is

S=H

(U)=0 , as it is dropped

a=g

Now. case 1

$S=ut+ \frac{1}{2} a {t}^{2}$

$H=(0)t+ \frac{1}{2} g (T)²$

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

Now.case 2

S=2H

t is time taken for 2H

$2H= \frac{1}{2} g(t)²$

$2[( \frac{1}{2} )g {T}^{2}] = \frac{1}{2} g(t)^{2}...using\:(1)$

$T²= \frac{1}{2} t² \\ 2T²=t² \\ t= \sqrt{2} T$