If the velocity-time graph has the shape AMB, what would be the shape of the corresponding acceleration-time graph?

The velocity (v) and time (t) graph of a body in a straight line motion is shown in the figure. The point S is at 4.333 seconds. The total distance covered by the body in 6 s is :

A helicopter rises from rest on the ground vertically upwards with a constant acceleration g. A food packet is dropped from the helicopter when it is at a height h. The time taken by the packet to reach the ground is close to :
[g is the acceleration due to gravity]

A Tennis ball is released from a height h and after freely falling on a wooden floor it rebounds and reaches height $${h \over 2}$$. The velocity versus height of the ball during its motion may be represented graphically by :
(graph are drawn schematically and on not to scale)