If some links in a mechanism can move in more than one direction, it is termed as?

• A. Incompletely constrained motion
• B. Partially constrained motion
• C. Completely constrained motion
• D. Successfully constrained motion

Answer: (A)

When a mechanism allows links to move in more than one direction, it signifies that the movement isn’t confined to a single path or set of directions. This situation is described as incompletely constrained motion. In this context, the term "incomplete" indicates that the constraints applied to the movement of the links are not sufficient to restrict the motion fully; hence, the links can exhibit multiple degrees of freedom.

In contrast, other terms imply varying levels of constraint. Completely constrained motion would mean that the links can only move in one specific manner based on the constraints imposed, which is not the case here. Partially constrained motion would describe a situation closer to complete constraint but allows for some variability in movement, though still less than what is seen in incompletely constrained scenarios. Successfully constrained motion is not a standard term used in mechanics, which further supports why incompletely constrained motion is the correct choice in this situation.