A simple GUI for simple pendulum simulation. You can set the length and initial
angle of the pendulum. You can also change the acceleration due to gravity,
simulation speed and number of oscillations. You can plot different quantities
for example, t vs , t vs , phase space trajectory, etc. There are three
buttons: To start the simulation press Start button, if you want to pause the
simulation press Pause button, and if you want to reset the simulation press
Note : If you want to change any parameter such as length of pendulum first
pause or reset the simulation, the again start the simulation.