Question

a ball is thrown from a cliff of mass , m it reaches the bottom after 5 seconds then find the hieght from which ball was thrown

Answer 1

Using kinematic equation
$s = ut + \frac{at {}^{2} }{2}$
If initial velocity is zero equation reduces to
$s = \frac{a {t}^{2} }{2}$
Here a is acceleration due gravity ie. 9.8m/s
$\frac{1}{2} (9.8)( {5)}^{2} = 122.5 \: m$