What is the nature of the displacement-time graph of a body moving with constant acceleration?

Distinguish between the terms distance and displacement.

Study the speed-time graph of a body given below and answer the following questions:
$(i)$ What type of motion is represented by $OA$,$AB$ and $BC$?
(ii) Find positive and negative accelerations of the body.
(iii) Find the distance travelled by the body from $A$ to $B$.

What can you say about the motion of a body if its displacement$-$time graph is a straight line parallel to the time axis?

$A$ circular cycle track has a circumference of $314 \ m$ with $AB$ as one of its diameters. $A$ cyclist travels from $A$ to $B$ along the circular path with a velocity of constant magnitude $15.7 \ m s^{-1}$. Find the:
$(a)$ distance moved by the cyclist.
$(b)$ displacement of the cyclist,if $AB$ represents the north-south direction.
$(c)$ the average velocity of the cyclist.

Give an expression for the speed of an athlete if he takes time $t$ to complete one round of a circular track of radius $r$.