This question is incomplete, the missing diagram is uploaded along this answer below;
Answer:
the increase in the overturning moment is 10.1 × 10⁶ lb.ft/ft
Option c) 10.1 × 10⁶ lb.ft/ft id the correct answer
Explanation:
Given the data in the question and illustrated in the image below;
Hydrostatic force on Dam ( per unit length )
P = [tex]\frac{1}{2}[/tex] rH.H = [tex]\frac{1}{2}[/tex]rH² lb/ft
Now, Overturning moment;
M = R × P = H/3 × [tex]\frac{1}{2}[/tex]rH² = [tex]\frac{1}{6}[/tex]rH³ lb.ft/ft
so when H = 175 ft
M₁ = [tex]\frac{1}{6}[/tex]r × ( 175 )³ = [tex]\frac{1}{6}[/tex] × 62.4 × ( 175 )³
M₁ = 55737500
Also, When H = 185 ft
M₂ = [tex]\frac{1}{6}[/tex]r × ( 185 )³ = [tex]\frac{1}{6}[/tex] × 62.4 × ( 185 )³
M₂ = 65848900
∴ Increase in overturning moment will be;
⇒ M₂ - M₁ = 65848900 - 55737500
⇒ 10111400 ≈ 10.1 × 10⁶ lb.ft/ft
Therefore, the increase in the overturning moment is 10.1 × 10⁶ lb.ft/ft
Option c) 10.1 × 10⁶ lb.ft/ft id the correct answer
