The window at left displays an undriven frictionless spring system consisting of two masses (one cyan and the other yellow) and three springs. Along the right edge of this window scales show the deviation of each mass from its relaxed position; when both masses are positioned at their respective \(0\) points all three springs are relaxed. Mouse-clicking and dragging either mass resets the initial condition.

Check boxes below the spring image toggle display of the position and velocity of the two masses in the graphing window at upper right. To the right of these boxes is a readout of the values for the selected value of \(t\). If a velocity display is selected, a diamond appears to the left of the corresponding mass; dragging it specifies an initial velocity.

Clicking the [>>] key animates this system and causes graphs of the positions and velocities of the two masses to be drawn as selected. When the animation begins the key is replaced by [||]; selecting it halts the animation. When \(t\) reaches \(10\) the key is replaced by [<<]; selecting it returns \(t\) to \(0\); dragging it specifies an initial velocity.

Rolling over the graphing window creates crosshairs and a readout of \(t\) and \(x\). Depressing the mousekey suppresses the crosshairs.

Selecting [Show all \(t\)] at lower left will display the full time series for position and velocity as selected.

© 2013 H. Miller, J. Orloff, and J.-M. Claus