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

An object has moved through a distance. Can it have zero displacement? If yes,support your answer with an example.

State which of the following situations are possible and give an example for each of these:
$(a)$ An object with a constant acceleration but with zero velocity.
$(b)$ An object moving with an acceleration but with uniform speed.
$(c)$ An object moving in a certain direction with an acceleration in the perpendicular direction.

$A$ motorboat starting from rest on a lake accelerates in a straight line at a constant rate of $3.0 \, m s^{-2}$ for $8.0 \, s$. How far does the boat travel (in $m$) during this time?

Abdul,while driving to school,computes the average speed for his trip to be $20 \, km \, h^{-1}$. On his return trip along the same route,there is less traffic and the average speed is $40 \, km \, h^{-1}$. What is the average speed (in $km \, h^{-1}$) for Abdul's trip?

$A$ driver of a car travelling at $52\, km\, h^{-1}$ applies the brakes and accelerates uniformly in the opposite direction. The car stops in $5\, s$. Another driver going at $3\, km\, h^{-1}$ in another car applies his brakes slowly and stops in $10\, s$. On the same graph paper,plot the speed versus time graphs for the two cars. Which of the two cars travelled farther after the brakes were applied?