Question

A ball is thrown up under gravity (g = 10m/sec). Find its
velocity after 1.0 sec at a height of 10m IMP PMT 2010)​

Answer 1

$\sf Keep ~in~ mind ~that~ initial ~velocity~ (u)~ is ~0 \\\\\sf By~ Equation ~of~ motion,~ \\\\\sf \boxed {s=ut+\frac{1}{2}at^2}\\\\\sf here~u=0 \\\\\sf 20=at^2 \\\\\sf a=20m/s^2 \\\\\sf Now, ~ \boxed {v^2=u^2+2as} \\\\\sf v^2=2as \\\\\sf v^2=2x20x1 \\\\\sf v^2=40 \\\\\sf \boxed{\bf{v=2 \sqrt{10}m/s}}$