TGPSC HMWSSB Manager 2015 Paper 2 · Question 115
Question 115 of the TSPSC Manager (Engineering), HMWSSB, 2015: Paper 2 (Civil Engineering) (1 November 2015). Try it first, then open the answer and explanation.
The three member plane truss A-B-C-D, shown in Fig.4 supports a vertical load W at B. The magnitude of the force carried by member BD is ______.
- W (compressive)
- 0.5 W (compressive)
- (√3/2) W (compressive)
- 0.5W (tensile)
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Answer: (3) (√3/2) W (compressive)
AB and BC are both inclined at 30° to the horizontal, so A, B and C lie on one straight line, and BD (at 60° to the horizontal) is perpendicular to it. Resolving forces at B perpendicular to line ABC, only W and BD have components, so F_BD = W cos 30° = (√3/2)W, and since it pushes back on joint B it is compressive.