Which of the following is not a vector?

$A$ motorbike running at a speed of $90\, km h^{-1}$ slows down to $18\, km h^{-1}$ in $2.5\, s$. Calculate:
$(i)$ Acceleration
$(ii)$ Distance covered during the deceleration

What can you conclude about the motion of a body depicted by the velocity-time graphs $(i)$,$(ii)$ and $(iii)$ given below?

What is the average velocity of a particle when it returns to the starting point? Can its average speed be zero?

$A$ piece of stone is thrown vertically upwards. It reaches its maximum height in $3 \ s$. If the acceleration of the stone is $9.8 \ m s^{-2}$ directed towards the ground,calculate the initial velocity of the stone with which it is thrown upwards. Find the maximum height attained by it.

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 then accelerating.