ATRACTOR

The applet consists of what we call the viewing area (with a gray background) and menus with buttons, text boxes and value control bars (with a blue background). However, it is worth noting that, as we will see later, in some cases it is possible to also enter data directly into the display area.

Click on the image where you have questions.

Note: The following figures are non-manipulable images. In the figures marked with , if you hover the mouse over them you will see an animation.

The display zone is divided into four areas:

• in the area on the left, a pendulum formed by a ball of mass m, suspended by a string of length L, subject to the action of gravity of value g, is represented. The pendulum string rests on a «constraining» curve, which causes its useful length to decrease as the amplitude increases. Drag the ball to the desired starting position with the mouse;

• in the central area there is a representation of the potential, kinetic and total energies of the pendulum at each instant.

  Dragging the mouse in this area vertically allows you to zoom;

• in the right area (from top to bottom) are represented:
  • the graph of the function x(t) in which x(t) represents the measurement (in R) of the angle corresponding to the arc traveled by the ball from the vertical, at time t;
  • the graph of the speed of the ball as a function of time t.

The initial parameters of the pendulums can be modified:

• in the case of the initial angle value,
  • directly in the text box: ;
  • dragging the pendulum ball;

 

• in the case of the value of the length L, the mass m of the pendulum and gravity (g),
  • entering the values in the text boxes;

  

  • dragging the control bars.

  

Once these values have been chosen, click on the button , to see the simulation of the movement of the pendulums.

The menu has the following options:

• : to reset the time value (t = 0);
• :to return to the initial configuration.

The option , when selected, allows the «constraining curve» for the pendulum thread to be visible.

In the two areas on the right of the applet, try clicking on them with the right mouse button: you will get a menu with other options for manipulating objects.

Among the options, it allows you to have a resizable window of the area where you clicked - for more information, click here.

The flag, at the top of the applet, indicates the language used. If you wish, click on it and select another language:

By clicking , you can choose between:

• : access this instruction page;
• : accesses information about the applet version*.