You are here given the possibility to experiment with five sorts of pendulum :
All Java applets in the lab are organized like in this screen snapshot. In the center there is the animation area where the motion of the pendulum is shown. On the left-hand side in the parameter area, various parameters can be changed. In the measurement area either a stopwatch or an oscilloscope is available to measure certain properties of the system.
The parameter area shows control panels for several parameters. Each panel shows its verbal name (not the mathematical one!) together with its physical units. Its actual value is shown in a text field. It can be changed either by manipulating the scrollbar or by putting some numbers directly into the text field. Note, that parameters with fixed values are not shown.
The animation is stopped by pressing the stop button. The motion is resumed by pressing it again. Note, that stopping the animation also stops the stopwatch and the oscilloscope. The motion is also stopped by clicking and dragging with the mouse pointer inside the animation area. In addition, the position of the pendulum is also changed according to the mouse pointer. Thereby, the angular velocity is put to zero. The actual value of the angle (in degree) is shown in the lower left corner. The driving mechanism is visualized in the following way: A periodically stretched rubber band of zero equilibrium length shows driving by a sinusoidal force (left part of the figure). A driven support is visualized by showing the lever mechanism (right part of the figure).
Stopwatch It works similar to an ordinary stopwatch. It has three different phases which are indicated by the label of the leftmost button. In the stopped state it shows "Start". In the running state it shows "Lap" or "Run" depending on whether the display is updated constantly or not. In the stopped state the stopwatch is started by pressing the leftmost button. The stop and the reset buttons stop the stopwatch. In addition the reset button resets the display to zero. The simulation time runs parallel to the physical time. Nevertheless, the stopwatch doesn't show the physical time because stopping the animation also stops the stopwatch. Its like freezing the time. After animation is restarted, the stopwatch runs again. The time increment is (roughly) given by the inverse frame rate which is 10Hz.
It is switch on by the on/off button. The type of triggering, the type
of the x- and y-axis, and the scales of the x- and y-axis can be
chosen from choice menus. Putting the mouse into the black screen
turns the default cursor into a cross-hair cursor. In addition, its coordinates are shown.