Which force term is omitted within the virtual work equation_______________?
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Answer: D. all of the above
Explanation
Ideal constraints do not perform mechanical work because their reactions are perpendicular to motion paths. Smooth contact surfaces exert forces normal to sliding directions resulting in zero displacement work. Fixed pivot axes cannot move so any reaction force there produces zero virtual displacement. The principle of virtual work simplifies complex mechanical equilibrium problems by ignoring internal reactions. Virtual displacement refers to an imaginary infinitesimal movement consistent with structural constraints. Conservative systems equate total virtual work done by active forces to zero at equilibrium.
Mechanics problems involving multiple connected bodies become much easier to solve using this principle. Analyzing linkage mechanisms in mechanical engineering often benefits from omitting passive constraint reactions. Frictionless rollers and pinned joints are common ideal constraints found in structural analysis models. Option A covers smooth surfaces which are indeed omitted due to perpendicular reaction paths. Option B includes rolling without slipping where instantaneous contact points have zero velocity. Option C accounts for fixed hinges and axes which cannot undergo any spatial translation.
- Subject
- Engineering
- Category
- Civil Engineering
- Topic
- —
- Difficulty
- medium
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