Which of the following position-time $(s-t)$ graphs represents uniform acceleration?

For the following velocity-time graph, the average speed for the motion during first $80 \, s$ is

The graph between the displacement $x$ and time $t$ for a particle moving in a straight line is shown in the figure. Determine the sign of the acceleration of the particle for the intervals $OA$,$AB$,$BC$,and $CD$ respectively.

In the following velocity-time graph,the distance travelled by the body in metres is ............. $m$.

The velocity $v$ of a body moving along a straight line varies with time $t$ as $v = 2 t^2 e^{-t}$,where $v$ is in $m/s$ and $t$ is in $s$. The acceleration of the body is zero at $t =$

Between two stations,a train accelerates uniformly at first,then moves with constant velocity,and finally retards uniformly. If the ratio of the time taken is $1 : 8 : 1$ and the maximum speed attained is $60\,km/h,$ what is the average speed over the whole journey in $km/h$?