To set the inital conditions for a myPhysicsLab simulation
click the “rewind” button to both pause the simulation and set its variables
to the stored intial conditions at time zero. Or give the reset command in the
Terminal command line which does the same thing.
for many simulations you can move the objects around to the initial positions by dragging with mouse or touch.
to set initial velocity, use the Terminal command line.
Initial positions can also be set here. The values command shows the names and
current values of all available variables. In the Double Pendulum simulation you
would see
SIM_VARS.ANGLE_1=0.39269908169872414;
SIM_VARS.ANGLE_1_VELOCITY=0;
SIM_VARS.ANGLE_2=0;
SIM_VARS.ANGLE_2_VELOCITY=0;
> symbol indicates what was entered).> angle_1 = 1
1
> angle_1_velocity=2
2
enter the save command to save the current initial conditions. The next time
you click “rewind” the simulation will return to this state.
click the “play” button, or give the resume command to run the simulation.
The above instructions use the EasyScript feature of myPhysicsLab. Customizing with EasyScript has more information.
To set initial conditions using Javascript
click the “rewind” button to both pause the simulation and set its variables
to the stored intial conditions at time zero. Or give the reset command in the
Terminal command line which does the same thing.
give the vars command in Terminal to confirm that varsList is an available
variable.
enter prettyPrint(varsList) in Terminal to see the variables listed
with their index number and value. For the Double Pendulum simulation it looks like
this
(0) ANGLE_1: 0.39270,
(1) ANGLE_1_VELOCITY: 0.00000,
(2) ANGLE_2: 0.00000,
(3) ANGLE_2_VELOCITY: 0.00000,
(4) ACCELERATION_1: -6.54247,
(5) ACCELERATION_2: 6.04446,
(6) KINETIC_ENERGY: 0.00000,
(7) POTENTIAL_ENERGY: 2.98392,
(8) TOTAL_ENERGY: 2.98392,
(9) TIME: 0.00000,
enter varsList.setValue(0, 1); varsList.setValue(1, 2) to set angle-1
and its velocity. Or use any other
VarsList methods
or JavaScript code.
enter the save command to save the current initial conditions. The next time
you click “rewind” the simulation will return to this state.
click the “play” button, or give the resume command to run the simulation.
Customizing with JavaScript has more information about using JavaScript with myPhysicsLab.