This applet simulates a simple two dimensional collision between
two objects of equal mass. After the applet loads, two balls
will appear, a red one and a blue one. The blue one is the
"target". Drag the red ball up or down to establish the impact
parameter, b. Then type an initial velocity between 0 and 100 in
the "Vxi" field for the red ball. Finally press the "Go" button
to begin the simulation. When the simulation is done, press
"Reset" to try a new one. Press "Stop" at any time to pause the
simulation. Press "Go" to continue.