[Daily Question] Theoretical Basis 2020.03.18
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Multiple choice questions: The two rods of the structure shown in the figure have the same area and material. Under the action of vertical force F, the rod whose tensile normal stress reaches the allowable stress first is (). (A) Pole 1 (B) Pole 2 (C) Reached at the same time (D) Unsure of the answer: B Tips: Those who can explain the problem-solving process will be given extra rewards, and the answers will be visible in the replies!
B At point C, the forces are balanced, the horizontal resultant force is 0, and the horizontal component of force F1 along rod 1 is F1* cos45°, with the horizontal component F2 of the force F2 along rod 2 * cos60°, F1 * cos45°=F2 * cos60°, cos45°>cos60°, then F1