I spent about 30-45 minutes trying this out. The item consists of four applets. The first represents cannon balls colliding...
I spent about 30-45 minutes trying this out. The item consists of four applets. The first represents cannon balls colliding with a railway car. The remaining three represent the collision of two railway cars, one of which is initially at rest. The applets contribute little to the conceptual understanding of momentum or its conservation. Two can be used to test quantitative predictions, but only for totally inelastic collisions (assuming that the cannon ball collisions are totally inelastic, which is not stated nor subject to confirmation). The remaining two can be used as tests of students' ability to perform quantitative calculations involving momentum conservation in totally inelastic collisions. Two of the four questions with the first applet require only the ability to count; that is, no physics understanding is required on the part of the student. Furthermore, the lack of specification of units reinforces the undesirable tendency of students to ignore units. Most annoyingly, some of the applets are VERY slow to develop.Technical Remarks: Two of the four applets do not load under Netscape Communicator (4.75) The motion of the rail cars is rather jerky under IE 5.5.