Which of the following velocity-time graphs is physically not possible?

The position $(x)$ of a particle moving along the $x$-axis varies with time $(t)$ as shown in the figure. The average acceleration of the particle in the time interval $t=0$ to $t=8 \, s$ is ........... $m/s^2$.

From the $v-t$ graph,find the total distance covered by the car in time $t = t_1 + t_2$.

$A$ particle starts from rest and moves in a straight line. It travels a distance $2L$ with uniform acceleration and then moves with a constant velocity for a further distance of $L$. Finally,it comes to rest after moving a distance of $3L$ under uniform retardation. Then the ratio of average speed to the maximum speed $\left(\frac{\bar{V}}{V_m}\right)$ of the particle is

The acceleration versus velocity graph of a particle moving in a straight line starting from rest is as shown in the figure. The corresponding velocity-time graph would be:

$A$ car starts from rest and travels with uniform acceleration $\alpha$ for some time and then with uniform retardation $\beta$ and comes to rest. If the total travel time of the car is $t$,the maximum velocity attained by it is given by: