Two cars, side by side, start from rest and travel along a straight road. The velocity of Car $A$ is given by $v=f(t),$ and the velocity of $\operatorname{Car} B$ is given by $v=g(t) .$ The graphs of $f$ and $g$ are shown in the figure. Are the cars still side by side after $T$ sec? If not, which car is ahead of the other? Justify your answer.