The displacement of a particle as a function of time is shown in Figure. It indicates :-
Let $v$ and $a$ denote the velocity and acceleration respectively of a body
A man in a balloon rising vertically with an acceleration of $4.9\, m/sec^2$, releases a ball $2\, seconds$ after the balloon is let go from the ground. the greatest height above the ground reached by the ball is ..........$m$ :-