A Problem Solving Framework
Based on the work of
Heller & Heller
University of Minnesota
The traditional “GUESS” method





Givens - Identify the “given” information
Unknown - Identify what is wanted
Equation - Select equation for solution
Solution - Solve equation for unknown
Survey - Make certain solution is realistic
Physics Problem-Solving
Strategy
 A better metacognitive approach to solving problems
 Provides students with a more structured approach to
solving problems, especially early on in the semester
 5 steps:
 Focus on the problem
 Describe the physics
 Plan the solution
 Execute solution plan
 Evaluate the solution
Focus on the Problem
Construct a
mental image
of the
sequence of
events
described in
the problem
statement.
Sketch a
picture that
represents this
mental image;
include given
information.
Determine the
question.
Select
approach(es)
that you think
will lead to a
solution of the
problem.
Describe the Physics
Construct
diagram(s) to
show
important
space and time
relationships
of each object.
Make sure all
symbols
representing
quantities
shown on
diagram(s) are
defined.
Declare a
target quantity.
State
mathematical
relationships
from
fundamental
concepts and
specific
constraints.
Plan a Solution
Choose one of
the quantitative
relationships
that involves
the target
variable.
Substitute
specific
variable
symbols into
general
equations;
drop variables
with zero
value.
Are there
additional
unknowns?
Choose a new
equation that
involves the
new unknown;
Yes
substitute
specific
variable
symbols.
No
Outline how to
use the specific
equations to
determine the
target variable.
Execute the Plan
Select the last
(unused)
equation from
your plan, and
isolate the
unknown
quantity.
Substitute this
relationship
into each of the
other equations
in the plan.
No
Has the target
variable been
isolated?
Check each
Yes term for the
correct units.
Compute the
value for the
target variable
and answer
original
question.
Evaluate the Solution
Check that the
answer is
properly
stated.
Is the answer
reasonable?
Review
problem
No
solution; make
corrections.
Yes
Determine if
the answer is
complete.
Using the Competent Problem
Solver Answer Sheet: Example 1
 An airplane lands on a runway at 175mph.
The plane uniformly slows to a stop over a
distance of 4049ft. What is the average
acceleration in meters/second squared?
How many g’s does this represent?
Using the Competent Problem
Solver Answer Sheet: Example 2
 A car’s initial mass and velocity are m and v
respectively. A truck’s mass and velocity
are M and -V respectively. Assuming a
head-on collision where they stick together,
what is the speed of the vehicles
immediately after the collision? The truck is
twice the mass of the car; the speed of the
car is one-half that of the truck.
Using the Competent Problem
Solver Answer Sheet: Example 3
 A toy rocket leaves the surface of the Earth
with an acceleration of 35m/s2. After 1.3s,
the rocket engine expires. Assuming no
wind resistance as it coasts upward, how
high does the rocket go?