What can you say about the motion of an object if its speed-time graph is a straight line parallel to the time axis?

$A$ farmer moves along the boundary of a square field of side $10 \, m$ in $40 \, s$. What will be the magnitude of displacement (in $m$) of the farmer at the end of $2 \, min \; 20 \, s$ from his initial position?

$A$ stone is thrown in a vertically upward direction with a velocity of $5 \, m s^{-1}$. If the acceleration of the stone during its motion is $10 \, m s^{-2}$ in the downward direction,what will be the height attained by the stone and how much time will it take to reach there?

$A$ train starting from a railway station and moving with uniform acceleration attains a speed $40 \, km \, h^{-1}$ in $10$ minutes. Find its acceleration (in $m / s^{2}$).

$A$ trolley,while going down an inclined plane,has an acceleration of $2 \,m \,s^{-2}$. What will be its velocity (in $cm \,s^{-1}$) $3 \,s$ after the start?

What is the nature of the distance-time graphs for uniform and non-uniform motion of an object?