What is the maximum acceleration of the train during the journey in $km \ h^{-2}$?

The $x-t$ graph of a particle moving along a straight line is shown in the figure. The $v-t$ graph of the particle is correctly shown by:

For the velocity-time graph shown in the figure,the distance covered by the body in the last two seconds of its motion is $S_1$. What is the ratio of $S_1$ to the total distance covered by it?

The $x-t$ graph for a uniformly accelerated particle is as shown in the figure. Find the average velocity between points $(i)$ and $(ii)$ in $ms^{-1}$.

$A$ body starts from rest and travels a distance $S$ with uniform acceleration,then moves uniformly a distance $2S$ and finally comes to rest after moving further $3S$ under uniform retardation. The ratio of the average velocity to maximum velocity is

Suggest a suitable physical situation for the following $x-t$ graph.