http://www.walter-fendt.de/ph11e/acceleration.htm
This is an interactive applet that allows the student or teacher to change the velocity and acceleration of a car. There is a graphical representation of the car and the velocity vector as it moves across the top of the screen. On the bottom are three graphs that show the distance v time, the velocity v time, and the acceleration v time. I wish I had found this a month ago, it would have been helpful explaining these principles.