Why Do Reaction Forces Differ When Isolating Different Members in Statics?

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SUMMARY

The discussion centers on the differences in reaction forces when isolating various members in statics problems. Specifically, the user encountered a scenario where isolating two or three members resulted in consistent reaction forces of W/3, while isolating a single plank yielded different reaction forces at each contact point. This discrepancy highlights the importance of applying the three general equilibrium equations correctly and considering the entire system's interactions.

PREREQUISITES
  • Understanding of static equilibrium and the three equilibrium equations.
  • Familiarity with reaction forces in structural analysis.
  • Basic knowledge of free body diagrams.
  • Experience with isolating members in statics problems.
NEXT STEPS
  • Review the principles of static equilibrium in mechanics.
  • Study the application of free body diagrams in isolating members.
  • Learn about the effects of load distribution on reaction forces.
  • Explore common mistakes in calculating reaction forces in statics.
USEFUL FOR

Students and professionals in engineering, particularly those studying statics, structural analysis, or mechanics, will benefit from this discussion.

AdamMcParland
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Homework Statement


I found this question and thought the situation was quite an interesting one.[/B]
upload_2015-12-25_22-26-9.png


Homework Equations


Seem to only be the 3 general equilibrium form of equations.

The Attempt at a Solution


The problem I encountered with this question was that when I isolated 2 or 3 members out of the system I got an answer for the reaction forces as W/3 but when I isolated only one plank, the equations suggested that the reaction forces were different at each point of contact. Has me mind boggled, all replies would be greatly appreciated, thank you![/B]
 
Physics news on Phys.org
Hi Adam,
1. Show your work. Perhaps someone sees where something goes awry.
2. Make is side view showing all the forces.
 

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