Constraints and Statical Determinacy

[sami23]

Homework Statement

Which of these bodies has redundant constraints for the given loading conditions? F_1 and F_2 are applied, known forces. In the first choice, the support at A is fixed and a cable connects points B and C. In the second choice, the support at A is a smooth pin, and a cable connects points B and C. In the third choice, the support at A is a single thrust bearing, and a cable connects points B and C.
Check all that apply.

Homework Equations

Redundant constraints - when a body has more supports than necessary to hold it in equilibrium it becomes statically indeterminate.

The Attempt at a Solution

the first and last seem to have redundant constraints.

 

[Quinzio]

agree about a and b, but not about c.