Velocity-time graphs show how the velocity (or speed) of a moving object changes with time. These graphs also show if the object is moving at a constant speed or accelerating, decelerating, or still.

National 5 Velocity-time graphs Speed-time graphs Velocity-time graphs are used to describe the motion of objects which are moving in a straight line.

Here is what I get. Since the acceleration is defined as the change in velocity divided by the change in time, the slope of a velocity-time graph will be the acceleration of the car.

Suppose that the biker's velocity function is given by the graph below on the time interval $0 \le t \le 4$ (where $t$ is measured in hours), and that $s (0) = 1$.