Question

A body projected vertically upward from the ground is at same height $h$ from the ground at two instant of time $t_{1}$ and $t_{2}$ (both measured from instant of projection). Then velocity of projection

• A. $\frac{g}{2}\left(t_{1}+t_{2}\right)$
• B. $g\left(t, t_{2}\right)$
• C. $g\left(t_{1}+t_{2}\right)$
• D. $\frac{g}{4}\left(t_{1}+t_{2}\right)$

Answer 1

Answer: (A)

$t_{1}+t_{2}=\frac{2 v}{g}$
$u=\frac{g}{2}\left(t_{1}+t_{2}\right)$
$h=u t_{1}-\frac{1}{2} g t_{1}^{2}=\frac{g}{2} t_{1} t_{2}$