The following table shows the position of three persons between $8.00\, am$ to $8.20\, am$.

Time	Position of Person $A$ $(km)$	Position of Person $B$ $(km)$	Position of Person $C$ $(km)$
$8.00\, am$	$0$	$0$	$0$
$8.05\, am$	$4$	$5$	$10$
$8.10\, am$	$13$	$10$	$19$
$8.15\, am$	$20$	$15$	$24$
$8.20\, am$	$25$	$20$	$27$

$(i)$ Who is moving with constant speed?
$(ii)$ Who has travelled the maximum distance between $8.00\, am$ to $8.05\, am$?
$(iii)$ Calculate the average speed of person $A$ in $km\, h^{-1}$.

The following graph describes the motion of a girl going to meet her friend who stays $50 \ m$ from her house.
$(i)$ How much time does she take to reach her friend's house?
$(ii)$ What is the distance travelled by the girl during the time-interval $0$ to $12$ minutes?
$(iii)$ During which time-interval is she moving towards her house?
$(iv)$ For how many minutes was she at rest during the entire journey?
$(v)$ Calculate the speed by which she returned home.

Which of the following figures (Fig.) represents uniform motion of a moving object correctly?

$(a)$ What is acceleration? Write its $SI$ unit.
$(b)$ Draw velocity-time graphs for an object having:
$(i)$ Uniformly accelerated velocity.
$(ii)$ Uniformly retarded velocity.

In a long distance race,the athletes were expected to take four rounds of the track such that the finish line was the same as the start line. Suppose the length of the track was $200 \ m$.
$(a)$ What is the total distance to be covered by the athletes?
$(b)$ What is the displacement of the athletes when they touch the finish line?
$(c)$ Is the motion of the athletes uniform or nonuniform?
$(d)$ Is the displacement of an athlete and the distance moved by him at the end of the race equal?

What is the difference between uniform motion in a straight line and uniform circular motion?