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Unformatted text preview: example, if we have two unknown vertical forces and one unknown horizontal force, then solve for the horizontal force first using ∑ FX = 0. 3. If the answer for an unknown comes out as negative number then the direction of the unknown force is opposite to that drawn on the FBD. APPLICATIONS
For a given load on the platform, how can we determine the forces at joint A and the force in the link (cylinder) BC? A steel beam is used to support roof joists. How can we determine the support reactions at each end of the beam? TWOFORCE MEMBERS
The solution of some equilibrium problems can be simplified if we can recognize members that are subjected to forces at only two points (e.g., at points A and B). Applying the equations of equilibrium to such member one can determine the resultant forces at A and B. These resultants must be equal in magnitude and act in the opposite directions along the line joining points A and B. EXAMPLE
Twoforce Members In the above figures, since the directions of the resultant forces at A and B are known (along the line joining points A and B), all AB members can be considered twoforce members if their weights are neglected. This...
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This note was uploaded on 10/31/2010 for the course CEE CE 221 taught by Professor Baladi during the Fall '10 term at Michigan State University.
 Fall '10
 Baladi
 Equilibrium

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