Help - Collisions 1D

The Collisions 1D applet simulates elastic and inelastic one-dimensional collisions in both the lab and centre of mass frames.

Click on a number to view the explanation of the corresponding item

1. Drawing Panel
   The top half of the display panel shows the collision from the centre of mass (CM) frame of reference. In this frame, the centre of mass is always at rest. You have the option to view or hide this frame of reference (see Options Panel).
   
   The bottom half of the display panel shows the collision from the lab frame of reference. In this frame of reference, the green mass is initially at rest. This frame of reference is always displayed.
   
   You have the option of printing the display panel. Right click the mouse in the display panel - a drop down menu will appear with the applet controls and the print command. Selecting print will provide a print preview and from there you may print the display panel.
   
   
   

2. Options Panel
   The options panel allows you to view or hide various applet options:
   
   

   	Show CM - this option allows you to view or hide the centre of mass (CM). When visible, the CM is shown as a red dot, located on the axis between the masses. By default, this option is checked on.
   	Show CM Frame - this option allows you to view or hide the centre of mass frame (CM frame). When checked on, both the CM frame and the lab frame are shown. When unchecked, only the lab frame is visible. By default this option is checked on. The CM frame shows the collision from the frame of reference of the centre of mass.
   	Show Trails - this option allows you to view or hide the path travelled by each mass and the CM before, during and after the collision.

   
   Clicking the up arrow () will hide the options panel. The button will switch to the down arrow () - clicking this will show the panel again.
   
   
   

3. Control Panel
   The applet is controlled by these buttons:
   
   

   	New - sets up a new collision scenario.
   	Back - allows you to go backward, step by step.
   	Play - press to begin simulation. When you press play, this button turns into the pause button.
   	Pause - press to pause simulation. When you press play, this button turns back into the play button.
   	Forward - allows you to go forward, step by step.
   	Reset - will reset that particular scenario to start again from the beginning.
   	Options - allows you to set collision conditions. You may select either random or manually input values for the coefficient of restitution and the masses of the balls.
   	Data - pressing this will open a box with information about the collisions, the masses and the centre of mass.

   
   

   Initial Velocity - this slider adjusts the initial velocity of the blue ball in the lab frame. The velocity may range between 0.1 m/s and 10 m/s.

   
   

   The applet can also be controlled by a drop down menu or with keyboard shortcuts. Right click in display panel - the menu will appear, just like the one to the right. The buttons are all listed, along with their shortcuts. Clicking the down arrow () will hide the control panel. The button will switch to the up arrow () - clicking this will show the panel again.