Topic: Engineering Mechanics
A perfect frame is that which satisfies the equation (Assume n = No of members and j = No. of joints)
- A. n = 3j - 2
- B. n > 3(j - 1)
- C. n < 3(j - 1)
- D. n = (2j - 3)
Answer: D. n = (2j - 3)
Explanation: For a 2D pin-jointed truss or frame with 'j' joints and 'n' members, it is classified as a perfect frame if it exactly satisfies the condition n = 2j - 3. If n < 2j - 3, the frame is deficient (imperfect or unstable). If n > 2j - 3, the frame is redundant (statically indeterminate).