This Demonstration simulates a spring pendulum moving in a vertical plane with damping. You can adjust the initial conditions and spring parameters, then start the simulation. The damping force is proportional to the velocity of the moving mass. Forces acting on the moving body can be shown in real time.
This Demonstration shows how the body moves in the first 50 seconds. If forces are too large or too small in appearance, you can rescale them.
With the path shown, you can draw beautiful Lissajous-like figures.