Modeling a Pump Jack

In the following model, drag Point E along the circle to simulate the pum jack. Don't forget to PLAY with the four parameters and the position of Point D and Point A. Enjoy the simulation and think of ways to save energy and the planet Earth!
1) What is the point in making such a model and simulation, mathematically speaking? 2) For students to start on such a project, what do they need to know? 3) How is modeling related to general mathematical problem solving strategies? 4) Be to honest, I had no idea what I might do when I wanted to give it a try. It is simple and a bit complex. 5) This project was prompted by the oil leak in the Gulf when I tried to find it how oil is pumped from under the ground.