PHYSICS PROBLEM SOLVING

(^) Example of Group 4D
Group 4D consisted of one woman (CB) and two male students (ME and ST).
Based on their individual cumulative exam scores at the time of this problem session, this
was a below average group (z = -.81). All three students were full-time, residential
students at the University. ST was identified as the Recorder. This group also lacked
some physics knowledge due to ST being the only one in class the day before when the
instructor did another similar problem as an example.
(^) ST: Were you, you were in class yesterday, weren't you?
ME: No. CB: You're the only one. [i.e., who was in class]
ST: Oh, and I don't remember this. [covers face with palms] ME: I was drained, I was drained two days...
Such self-disclosures were useful in identifying poorly prepared groups. Their
lack of physic knowledge influenced their approach to solving the problem. In the dialog
segment in Table 3-12 (page 96), the students coax the teaching assistant into giving a
hint. Although the teaching assistants were discouraged from directly answering
questions, they would occasionally intervene to make a point about the physics. Dialog
sections in which there was considerable teaching assistant intervention were not
included in the analysis procedure. This segment is included here as an example of a
teaching assistant intervention.
An error in the construction of the free-body diagram eventually led to a mistake
in the writing of the equations for the equilibrium condition. They neglected to place the
weight of the strut in the center of the strut. Later, when finding the torques, they used a
moment arm of 2 meters instead of 1.5 meters. A sketch of their free-body diagram
appears in Table 3-13 (page 97) opposite line 22.