The Ejs Coupled Oscillators and Normal Modes model displays the motion of coupled oscillators, two masses connected by three springs.  The initial position of the two masses, the spring constant of the three springs, the damping coefficient for each mass, and the driving force and driving force frequency for the left mass can be changed via text boxes.  You can modify this simulation if you have Ejs installed by right-clicking within the plot and selecting "Open Ejs Model" from the pop-up menu item.  

Ejs Coupled Oscillators and Normal Modes model was created using the Easy Java Simulations (Ejs) modeling tool.  It is distributed as a ready-to-run (compiled) Java archive.  Double clicking the ejs_ehu_oscillations_normal.jar file will run the program if Java is installed.  Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models.  Additional Ejs models for classical mechanics are available.  They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

Please note that this resource requires at least version 1.5 of Java (JRE).