Which statement regarding instantaneous centers is incorrect____________________?
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Answer: D. the double centre can be denoted either by 02 or Ol2, but proper selection should be made
Explanation
Double centers in mechanism analysis represent coincident instantaneous centers for links in multi-loop chains. Standard notation uses two digits separated by a comma or written together like O_12 to denote specific centers. Option D claims that double centers can be denoted interchangeably as O_2 or O_12, which violates proper subscript rules. Aronhold Kennedy theorem states that three bodies having relative planar motion have instantaneous centers on a line. Instantaneous centers simplify velocity analysis by treating complex mechanisms as pure rotation points momentarily. Proper subscript notation is vital to avoid confusion when applying Kennedy theorem to complex multi-bar linkages.
Statement A correctly defines an instantaneous center as a point of zero relative linear velocity between two links. Statement B correctly notes that two rigid links share no linear velocity relative to each other at their center. Statement C correctly describes how instantaneous centers relate the linear velocities of multiple connected links.
- Subject
- Engineering
- Category
- Mechanical Engineering
- Topic
- —
- Difficulty
- medium
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