Question

A ball is released from a height and it reaches the ground in $3s$. If $g=9.8m{s}^{-2}$, find
(a) the height from which the ball was released and
(b) the velocity with which the ball will strike the ground.

• A. (a) $88.2$ $m$ , (b) $29.4$ $m$ $s^{-1}$
• B. (a) $44$ $m$, (b) $25$ $m$ $s^{-1}$
• C. (a) $49$ $m$ , (b) $29.4$ $m$ $s^{-1}$
• D. (a) $44.1$ $m$ ,(b) $29.4$ $m$ $s^{-1}$

Answer 1

The correct option is D (a) $44.1$ $m$ ,(b) $29.4$ $m$ $s^{-1}$

$s=ut+0.5a{t}^2$
$s=\frac{1}{2}\times 9.8\times 9=44.1m$
$v=u+at$

$v=0+\left(9.8\right)\left(3\right)=29.4m/s$