Note: When running this simulation on a tablet or smart-phone, set the parameters, then press the Play button. When running this simulation on a computer, be sure to uncheck “Accelerometer,” then set the parameters and press the Play button.

Four-Spring Accelerometer

The Four-Spring Accelerometer mobile JavaScript model is intended to show how a mobile device detects acceleration. The simulation displays the forces and dynamics of a small mass connected to four walls by springs and it is designed to use the accelerometer on your mobile device to respond to the direction of the gravitation field g and the mobile device's xy-acceleration. You may need to lock the orientation of your screen to maintain a fixed view as you tilt your device. For use on computers without an accelerometer or for classroom use, uncheck Sensor to simulate a tilted device in the view.

A force body (free body) diagram showing the spring force (blue), the gravitational force (black), and the force of friction (green) is shown. Users can set the initial position, velocity, and the viscous damping (friction) coefficient using the input fields above the buttons. Test your understanding of how the accelerometer works by answering the questions and comparing your answers with the simulation results. Remember to press the play button after you set the initial values to observe motion.

Initial values, such as x₀ and vx₀, should be set when the simulation is paused but not when the simulation is running. (Non-editable input fields have a grey background.) You may also drag the mass when the simulation is paused. The reset button returns the system to its default state while the reset time button returns the system to the previous values of x₀ and v₀.