problem in the basic engineering sciences, the following questions
help students formulate a solution:
What exactly are we trying
to find? What is known from the problem statement?
What is the system? (This
must be explicit to apply the accounting principles because they
are written for a system.)
What are the important
extensive properties to count? (This encourages students to think
in terms of the quantities found in the physical laws.)
What's the time intervalfinite
time, transient, or steady state?
How does the system interact
with its surroundings? (Interactions depend on the boundary selected
and the properties counted.)
What are the modeling assumptions
that can help us simplify the basic equations for this specific
How many equations are
required to solve for the unknowns?
If the accounting equations
are insufficient, what other equations (constitutive equations)
may be used to relate the unknowns in the problem?