If ballast of 60 lb is added at 60 inches, what is the new CG?

• A. CG ≈ 77.0 inches
• B. CG ≈ 75.5 inches
• C. CG ≈ 78.5 inches
• D. CG ≈ 76.2 inches

Answer: (A)

CG is the weighted average of all weights’ positions. When you add ballast, the overall CG shifts toward the ballast location in proportion to how heavy the ballast is relative to the total weight. You compute it with the moment balance: New CG = (W_initial × CG_initial + W_ballast × ballast_arm) ÷ (W_initial + W_ballast). Here the ballast is 60 lb at 60 inches, so it pulls the CG toward 60 inches. If the original CG was in the high 70s, this forward ballast causes a modest shift toward 60, and the resulting CG ends up near 77 inches. That’s why the closest approximation is about 77 inches. The other values would require a different initial weight/CG or a ballast at a different location.