Which quantity is measured by the area occupied below the velocity-time graph of an object in motion?

The driver of a car travelling at $72 {\mathrm{kmh}}^{-1}$ applies the brakes and accelerates uniformly in the opposite direction at the rate of $5 {\mathrm{ms}}^{-2}$. How long the car will take to come to rest? How far will the car cover before coming to rest.

The figure below shows the distance-time graph of three motorcyclists $A,B$ and $C$. On the basis of this graph answer the following questions:

Which of them is travelling fastest?

The figure below shows the distance-time graph of three motorcyclists $A,B$ and $C$. On the basis of this graph answer the following questions:

Are all the three ever at the same point on the road?

The figure below shows the distance-time graph of three motor-cyclists $A,B$ and $C$. On the basis of this graph answer the following questions:

When $B$ passes $A$ where is $C$?

The figure below shows the distance-time graph of three motorcyclists $A,B$ and $C$. On the basis of this graph answer the following questions:

How far did $C$ travel when $B$ meets $A$?

What type of motion is represented by each of the following graphs?