HOMEWORK AND BOARDWORK OPERATING PROCEDURES [82004 RJ Bieniek]
The following Operating Procedures for Homework (HW) and Boardwork (BW) will develop your
personal power and insight to solve problems thrown at you in homework, quizzes, or exams.
1. A full appropriate diagram or physical sketch must appear as the starting point of your solution.
2. In any derivation, your mathematics must begin with a correct rendition of an equation in the list
of Official Starting Equations (OSEs). (However, this need not be followed for purely
mathematical problems, such as those dealing solely with graphing or trigonometry.)
3. During steps of a derivation after the OSE, a physical quantity must eventually appear as an
algebraic symbol representing a magnitude, e.g. distance d, height h, initial speed vi , launch
angle θ, and free-fall acceleration magnitude g. For instance, substitute vi cosθ for vix just after
it first appears in an OSE, but keep vi cosθ through to the end before evaluating numerically.
4. If an axis-system label or an algebraic symbol for system distance, position or vector appears in a
mathematical step after the OSE, it must appear in the diagram. This helps to define what a
complete diagram is. These symbols can be added as you go, but they still must appear before
they are used in a mathematical step. If a vector is labeled, its components need not be.
5. If you use a vector component in your equations at some point (e.g., v0x in vx = v0x + ax t), then
you must draw the associated vector in your diagram (e.g., an appropriate arrow labeled by v0).
Also, lightly draw in components based on the chosen coordinate system with arrow at the
appropriate ends. You are advised not to label the components.
6. Carry the symbols associated with the magnitudes of system parameters and physical constants
down to the end of your derivation. Before substituting in numerical values for them, you must
box your algebraic answer with the desired quantity alone on one hand side of the
expression and relevant algebraic system parameters on the other. Then substitute in
numerical values and box the resulting numerical answer. In a multi-part question that requires
the answer for a prior part to do the part you are on, you can just use, if you wish, the symbol of
your answer to the prior part throughout your derivation and then make
the full algebraic substitution at the end. The only exception to this is for
quantities that require the solution of a quadratic equation; in such
v0
situations, you may substitute in numerical values at the end of the
algebra before solving for the desired value.
7. When substituting in numerical values and their units for the symbols in your final algebraic
answer, verify by unit analysis that your resulting numerical answer has appropriate units.
Unless the question specifically deals with significant figures, carry 3 significant figures
throughout your numerical work; e.g., if you are given a 3-kg mass, use 3.00 kg.
Official Starting Equations
A list of initial Official Starting Equations has been distributed to you. The Official Starting
Equations are comprehensive, and are all that you will need to do the homework and boardwork.
Component versions of vector OSE are also OSE. This means that vx = v0x + axt is as good an
OSE as v  vo  at . Appropriate identifying labels can be added as subscripts, including replacement
of 0 and i with labels associated with initial states, e.g., to determine 1-D velocity V in a constant
acceleration from A (initial) to B (final): VBx = VAx + ax t is equivalent to v  vo  at