The critical load for a long column is 160 kN. If the same section is to be used for another column of double length, then the critical load is
- A320 kN
- B160 kN
- C80 kN
- D40 kNCorrect
Solution
Concept
Euler buckling load
Formula
Pcr = π²EI / L²
Step-by-step solution
1. Pcr ∝ 1/L² for the same section and end conditions. 2. Length doubled ⇒ Pcr = 160/4 = 40 kN.
Explanation
Buckling load falls with the square of the length.
Why the other options are wrong
320, 160 and 80 kN ignore the square dependence.
Shortcut
Double length → ¼ load.
Common mistake
Dividing by 2.
Correct answer: D) 40 kN