The acceleration vs velocity graph of a particle moving in a straight line is shown in the figure. Then the slope of the velocity vs displacement graph

Two trains which are moving along different tracks in opposite directions are put on the same track due to a mistake. Their drivers on noticing the mistake, start slowing down the trains when the trains are $300 \mathrm{m}$ apart. Graphs given in the figure shows their velocities as function of time as the trains slow down. The separation between the trains when both have stopped is

The acceleration of a particle that moves along the positive $x$-axis varies with its position as shown in the figure. If the velocity of the particle is $0.8 \mathrm{m} {\mathrm{s}}^{-1}$, at $x=0$, then the velocity of the particle at $x=1.4 \mathrm{m}$ is (in $\mathrm{m} {\mathrm{s}}^{-1}$)