PHYSICS PROBLEM SOLVING

(^)
cable is too small." However, the diagram given with the problem statement clearly
shows the sign in an equilibrium position and thus the rebuttal is invalid. A rebuttal
usually begins with "unless," implying that situation is true unless other conditions apply.
(A rebuttal in kinematics might be, "Unless the object is moving at or near the speed of
light.") A rebuttal is not the same as a challenge to a claim.
A challenge is generated by the student and not by the inherent characteristics of
the problem. Although the Toulmin structure does not explicitly allow for a challenge, I
expected to see challenges because of the roles the students were introduced to in their
cooperative groups. The skeptic role is basically a challenging role.
GROUNDS
WB = 100N, WM = 200N,
L = 3 meters,  = 30
Picture  Equilibrium

WARRANTS
 F = 0

= 0
Vector components



CLAIM

Unknown forces can be

found by applying  F = 0

and  
 = 0.

 

BACKINGS

General validity of

Newton's Laws, nature of

vector algebra, both as expressed in the text, by

the professor, or teaching

assistant.

REBUTTAL

External forces (none are

indicated) could cause the

sign to collapse. Thus, rebuttal in this case. no

Figure 2-2. Toulmin Analysis of At The Gasthaus.