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 ...

Acceleration = change of velocity ÷ time taken.. Question. Find the rate of change of speed of an athlete, if she starts from rest (0 m/s) and she reaches a speed of 6 m/s in 12 seconds.