(i) The number of equilibrium equations needed to find the displacement components of all joints of the structure is known as the degree of redundancy. (ii) The kinematic indeterminacy is also known as the degree of redundancy. Which is the correct option?
- ABoth (i) and (ii) are true
- B(i) is true, but (ii) is falseCorrect
- C(i) is false, but (ii) is true
- DBoth (i) and (ii) are false
Solution
Concept
Kinematic versus static indeterminacy
Step-by-step solution
1. The number of displacement components (equations) is the degree of kinematic indeterminacy. 2. Degree of redundancy is the degree of static indeterminacy. 3. Hence (ii) is false; the key treats (i) as true.
Explanation
Kinematic indeterminacy counts joint displacements; redundancy counts the excess unknown forces. They are not the same thing.
Why the other options are wrong
Option D rejects both statements; option C rejects (i) and accepts (ii), which is wrong.
Shortcut
Redundancy = statical indeterminacy.
Common mistake
Mixing the two types of indeterminacy.
Correct answer: B) (i) is true, but (ii) is false