Disk Collision Applet
How It Works
The applet is able to accomplish the collision is by the use of vectors. Instead
of using the conservation of momentum or conservation of energy, the program uses
impact vectors to calculate the velocities of the disks after the collision.
It works by first calculating a direction vector from the center of disk1(red)
to the center of disk2(blue).
It then takes the velocity vector of the disk2 subtracts it by the velocity vector
of disk1 to form a resultant velocity vector..
Then the applet dots that resultant vector with the direction vector to determine the
speed of impact.
The direction vector is then scalar multiplyed by the product of the imactspeed and
the root of the product of the 2 disk's masses.
Then the direction vector gets divided by the mass of the corresponding disk and it
is added to the velocity of that disk
How To Use The Applet
- Enter the values for position, velocity, and mass into the input panel. (Note: The
units of velocity are gridspaces per second)
- When satisfied with the values, click start to engage the movement of the disks.
- While the disks are moving, you can display the disk's velocity vectors by checking
the "display vectors" checkbox
- As the disks move, they will generate their corresponding values in the table below,
these numbers will be generated every half second.
The benefit of the table to display the values of the disks, is the values can be
copied from the table and put into any spreadsheet program. The velocities of disks
of the same mass have been repeatedly tested and conserve both momentum and energy
with a typical inbalance of 1*10^-14, a miniscule number caused by the rounding
of the spreadsheet. If you want to try it out yourself, an excel spreadsheet can
be downloaded from this project's main page at