What kind of motion of a body is represented by the graphs given below?

$(a)$ Draw velocity-time graphs for the following cases:
$(i)$ When the object is at rest.
$(ii)$ When the object is thrown vertically upwards.
$(b)$ $A$ motorcyclist riding motorcycle $A$ who is travelling at $36 \, km \, h^{-1}$ applies the brakes and stops the motorcycle in $10 \, s$. Another motorcyclist of motorcycle $B$ who is travelling at $18 \, km \, h^{-1}$ applies the brakes and stops the motorcycle in $20 \, s$. Plot the speed-time graph for the two motorcycles. Which of the two motorcycles travelled farther before it came to a stop?

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

The velocity-time graph (Fig.) shows the motion of a cyclist. Find $(i)$ its acceleration $(ii)$ its velocity and $(iii)$ the distance covered by the cyclist in $15\,s$.

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.

The displacement-time graph of a body is parallel to the time axis. What will you infer about the velocity of the body?