(^) 51. In the middle. Cl Weight vector is at the center
- RM. Yeah, goes in the middle. Sp of the bar. Supports the previous
- MR. That [i.e., the weight] always goes in warrant.
the cen54. MK. OK, ster. o this is weight bar. [labels W Supports the previous claim.
diagram with WB while talking.] Sm This is a gmoving oRecorder sn. ood exummarizinample ofg bef the ore - M55. MRK. W. That should be athat? one end, 1.5 meters. RQCl G^ RQCl = RQ for Clarification.
- T57. MRhey alw. The ways do it feight ofrom the bar. the center. We Cl^
alwhave to knoays do it fw horom thw fae cenr over it is. [Indicating ter. We're going to
labels for the distances.]
C B
RQGC = DoB = “They a it from thlways do it.” e center.
RQG = Request for Grounds.- So it's always at 1.5. G Always at 1always in the m.5 imiddle, i.e., at plies it is
- MK. Oh, OK [Draws and labels the 1.5 the center of mass.
meters.] Sp^
WBT
30 o
1.5m- MR. Meters. Cl
Table 3-1. Group 4A, Lines 39-61.
The students in Group 4A had just written down the “Question” and identified the
principles they will use (equilibrium and torque). In this specific segment they are
beginning to draw the free-body diagram. In the first episode (lines 39 to 43) they
identify the diagrams (“free-body” and “force thingy”) they will draw in the Physics
Description. Member MK, who is the Recorder, makes the Claim (line 43) that they will
need to draw the bar before they can draw the free-body diagram. From identifying the
necessary diagrams in this episode they next go to a discussion of which forces to include
on their free-body diagram. This was a change of thought, and thus the new episode
takes over in line 44. The statement “And this is a weird force,” is difficult to interpret.