The Lagrange Applet has eight general parameters that determine the
basic functions of the applet. In addition, for each specific physical
system (such as, a double pendulum) there is a set of parameters that
determine the physical properties and initial condition of the system.
| Name | Possible Values | Description |
| type | DoublePendulum, SpringPendulum, DoubleSpring
| Physical system to be displayed.
|
| frames | a positive integer (10)
| Number of frames per second. |
| timefactor | a decimal fraction (1.0)
| Time factor for slow or fast motion. |
| trace | true, false
| Draw a trace? |
| controls | true, false
| Display a panel of control buttons? |
| showenergy | true, false
| Display the total energy? |
| constrainenergy | true, false
| Enforce energy preservation? |
| energycontrol | true, false
| Display button to toggle energy preservation? |
| deterministic | true, false
| Deterministic simulation? |
| bgcolor | #xxxxxx (getBackground())
| The background color. |
| fgcolor | #xxxxxx (#000000)
| The foreground color. |
| tracecolor | #xxxxxx (#ffffff)
| The color of the trace. |
| scalecolor | #xxxxxx (#000000)
| The color of the metric scale. |
| timecolor | #xxxxxx (#000000)
| The color of the time scale. |
| energycolor | #xxxxxx (#000000)
| The color of the energy display. |
| Name | Default | Description |
| m | 1 | mass, in kg |
| l0 | 1 | first spring length, in m |
| l1 | 1 | second spring length, in m |
| k0 | 5 | first spring constant, in N/m |
| k1 | 1 | second spring constant, in N/m |
| b | 1.9 | distance between pivot points, in m |
| g | 0 | gravity, in m/s^2 |
| x | 1.2 | initial value for coordinate of mass, to right of midpoint of pivots, in m |
| x' | 0 | initial derivative for coordinate of mass, to right of midpoint of pivots, in m |
| y | 1 | initial value for coordinate of mass, above midpoint of pivots, in m |
| y' | 0 | initial derivative for coordinate of mass, above midpoint of pivots, in m |
| Name | Default | Description |
| m0 | 2 | inner mass, in kg |
| m1 | 1 | outer mass, in kg |
| l0 | 6 | inner length, in m |
| l1 | 4 | outer length, in m |
| k0 | 60 | spring constant, in N/m |
| g | 9.81 | gravity, in m/s^2 |
| x | 2.2 | initial value for coordinate of inner mass, right of pivot, in m |
| x' | 0 | initial derivative for coordinate of inner mass, right of pivot, in m |
| y | 3 | initial value for coordinate of inner mass, above pivot, in m |
| y' | 0 | initial derivative for coordinate of inner mass, above pivot, in m |
| alpha | 1 | initial value for angle of outer leg, counterclockwise from south, in radians |
| alpha' | 0 | initial derivative for angle of outer leg, counterclockwise from south, in radians |
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