PHYSICS PROBLEM SOLVING

(^)
STATEMENT OF THE PROBLEM
Problem Solving
Traditionally, college physics teachers have emphasized problem solving as a way
to learn physics (Fuller, 1982). Teachers and students alike are not always satisfied with
their problem-solving efforts. One reason for this may lie in the different approach that
an expert (teacher) and novice (student) take to a problem (Larkin, McDermott, Simon
and Simon, 1980). Novices tend to concentrate on the superficial features of a physics
problem, whereas experts use principles of physics to analyze and solve a problem. For
example, a novice would examine a problem like At the Gasthaus (Figure 1-1, page 4),
see a sign suspended by a post and a cable, and interpret it as a "sign problem." On the
other hand, an expert would most likely see the same problem and interpret it as a "static
equilibrium problem." Novices also tend to immediately seek the proper equations that
will solve the problem. That is, they attempt a quantitative analysis of the problem
before constructing an adequate qualitative analysis.
(^) Above the entrance door of an old German
"GASTHAUS" hangs a sign. A 200 N metal beer
mug hangs at the end of a 3 meter long strut that is
attached to the wall by a hinge. The weight of the
strut is 100 N. A support cable is attached to the strut at a point 2 meters from the wall and makes a
30
angle with the strut. Find all the forces acting
on the strut. Useful information: F = 0 and 
=
0
GASTHAUS
Figure 1-1. AT THE GASTHAUS