Strongly reminiscent of this really fantastic talk from Eric Mazur, a Harvard physics professor (and a charismatic speaker!) who was shocked when he discovered the pervasive misconceptions held by his undergraduate students.
Mazur describes how he discovered and carefully measured the lack of fundamental understanding among the majority of his students, and how after attempting to address the problem in various ways, he found that a discussion-based, peer-assisted method of working through material was much more effective than more a lecture-oriented approach.
Thanks for that! You should submit this to the front page. Suggested title: "Students Ace Textbook-Style Physics Questions While Struggling With Basic Understanding."
On the hoop / disc question, I could figure out that there is more work involved in rotating the hoop so the disc would go faster. However, what if the incline of the surface is so extreme that both of them are falling? Surely in that case they should fall with equal speed, so alpha would seem to matter.
http://www.youtube.com/watch?v=WwslBPj8GgI
Mazur describes how he discovered and carefully measured the lack of fundamental understanding among the majority of his students, and how after attempting to address the problem in various ways, he found that a discussion-based, peer-assisted method of working through material was much more effective than more a lecture-oriented approach.