Out of the three speed$-$time graphs shown below

Identify the graph for the following cases.

$(i)$ A ball thrown vertically upwards and returning to the hand of the thrower ?

$(ii)$ A body decelerating to a constant speed and accelerating.

A body moves on three quarters of a circle of radius $r .$ The displacement and distance travelled by it are

The branch of Physics which deals with the motion of objects while taking into consideration the cause of motion is

The velocity$-$time graph of a truck is plotted below

$(a)$ Calculate the magnitude of displacement of the truck in $15$ seconds.

$(b)$ During which part of the journey was the truck decelerating ?

$(c)$ Calculate the magnitude of average velocity of the truck.

"The direction in which an object moves is given by the direction of velocity of the object and not by the direction of acceleration". Give an example to justify this statement