A particle is moving in a straight line and passes through a point $O$ with a velocity of $6\;m{s^{ - 1}}.$ The particle moves with a constant retardation of $2\;m{s^{ - 2}}\;$ for $4$ s and there after moves with constant velocity. How long after leaving $O$ does the particle return to $O$..........$s$
$3$
$8$
Never
$4$
A particle starts with an initial velocity of $10.0\,ms ^{-1}$ along $x$-direction and accelerates uniformly at the rate of $2.0\,ms ^{-2}$. The time taken by the particle to reach the velocity of $60.0\,ms ^{-1}$ is $.......\,s$
Derive the equations of uniformly accelerated motion by graphical method.