Key Concept: Always start your analysis with one or
more complete and accurate
free body diagrams.
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Strategy to Solve Equilibrium
Problems in a Plane
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1.
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Draw a FBD of one or more parts to identify the forces
(and possibly moments)
that act on each part. This is the key step. If incorrect, then all remaining
calculations will be for naught. |
2. |
Write equations of equilibrium
for each part. i.e. ∑ Fx
= 0, ∑ Fy = 0, ∑ Mpoint = 0 |
3. |
Check to see the unknowns. The unknowns may be forces, moments, or
perhaps
lengths. |
4. |
If
the number of unknowns equals the number of independent equations of
equilibrium, then proceed to solve for the unknowns.
If
the number of unknowns exceeds the number of independent equations of
equilibrium, then you need more information. More information may come
from additional free body diagrams along with the corresponding equations
of equilibrium, or perhaps relations from friction if that applies. |
5. |
Once you
have the same number of unknowns as number of independent
equations of equilibrium, then proceed to solve for the unknowns. |
Click here to
return to general equilibrium problems.
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