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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.


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Barbra Bied Sperling
Barbra Bied Sperling (Administrator)
19 years ago
I spent about 20-30 minutes with this item. At first glance, this is a very
appealing applet with a simple user interface and clear display. However, its
effectiveness as a teaching/learning aid is very limited. All calculations seem
to be correct (though not to the number of digits displayed). The impact
parameter is selected as an integer between 0 and 30 (inclusive) -- there is no
indication of the meaning of this number since none of the quantities have units
and the size of the balls is not given. The scattered angle is given as NaN for
an impact parameter of 0 -- most students will not know what this means. The
applet could be used as a lecture/demo to qualitatively show the relationship
between impact parameter and scattering angle, and the relationship of the
velocity components to momentum conservation. It is not of much use as a
quantitative interactive lecture demo, or as homework, or for drill and practice
because too much information is given -- nothing is left for students to figure
out. Students could use it to check an analytic solution to this special class
of collisions.