Answer:
W = 112 lb
Explanation:
Given:
- δb = 0.025 in
- E = 29000 ksi    (A-36)
- Area A_de = 0.002 in^2
Find:
Compute Weight W attached at C
Solution:
- Use proportion to determine δd:
               δd/5 = δb/3
               δd = (5/3) * 0.025
               δd = 0.0417 in
- Compute εde i.e strain in DE:
                εde = δd / Lde
                εde = 0.0417 / 3*12
                εde = 0.00116
- Compute stress in DE, σde:
                σde = E*εde
                σde = 29000*0.00116
                σde = 33.56 ksi
- Compute the Force F_de:
                F_de = σde *A_de
                F_de = 33.56*0.002
                F_de = 0.0672 kips
- Equilibrium conditions apply:
                (M)_a = 0
                3*W - 5*F_de = 0
                W = (5/3)*F_de
               W = (5/3)* 0.0672 = 112 lb
