Q. A man is $ 45\,m $ behind the bus, when the bus start accelerating from rest with-acceleration $ 2.5\,m/s^{2} $ . With what minimum velocity should the man start running to catch the bus?
J & K CETJ & K CET 2005
Solution:
In order that the man catches the bus, let his minimum velocity be $v$, then from equation of motion
$v^{2}=u^{2}+2 a s$
We have, $u=0$ (initial velocity),
$a=2.5 \,m / s ^{2} $
$s=45\, m $
$\therefore v^{2}=2 \times 2.5 \times 45$
$\Rightarrow v=\sqrt{225}=15\, m / s$
