A body starts from origin and moves along $x$-axis so that its position at any instant is $x=4 t^2-12 t$ where $t$ is in second and $v$ in m/s. What is the acceleration of particle is ............. $m / s ^2$
$4$
$8$
$24$
$0$
A body starts from rest with uniform acceleration $a,$ its velocity after $n\,seconds$ is $v$. The displacement of the body in last $3\,s$ is : (assume total time of journey from $0$ to $n\,seconds$ )
A train starting from rest accelerates uniformly for $100\,\,s,$ then comes to a stop with a uniform retardation in the next $200\,\,s.$ During the motion, it covers a distance of $3\,\,km.$ Choose the wrong option