A cantilever beam AB of length L and uniform flexural rigidity EI has a bracket AC attached to its free end shown in Fig. Vertical load is applied to the free end C of the bracket. In order that the deflection of point A to be zero the ratio a/L should be
- A. 1/2
- B. 1/3
- C. 1/4
- D. 2/3
Answer: D. 2/3
Explanation: Load P at C causes force P and moment $M=Pa$ at A. Downward deflection due to P: $PL³/3EI$. Upward deflection due to M: $ML²/2EI$. Equating: $PL³/3EI = (Pa)L²/2EI \Rightarrow L/3 = a/2 \Rightarrow a/L = 2/3$.