Two ballast items: 700 lb at 10 inches and 900 lb at 26 inches, total weight 1,600 lb; CG at ?

Two ballast items: 700 lb at 10 inches and 900 lb at 26 inches, total weight 1,600 lb; CG at ?

• A. 18 inches
• B. 20 inches
• C. 19 inches
• D. 21 inches

Answer: (C)

Center of gravity is the point where the entire weight can be considered to act. To locate it, multiply each ballast by its distance from the reference, sum those moments, and divide by the total weight. For 700 lb at 10 inches, the moment is 7,000 lb·in. For 900 lb at 26 inches, the moment is 23,400 lb·in. The total moment is 30,400 lb·in, and the total weight is 1,600 lb. Dividing gives 30,400 / 1,600 = 19 inches. So the center of gravity sits at 19 inches from the reference, between the two ballast placements and slightly toward the heavier 900 lb ballast at 26 inches.

Center of gravity is the point where the entire weight can be considered to act. To locate it, multiply each ballast by its distance from the reference, sum those moments, and divide by the total weight. For 700 lb at 10 inches, the moment is 7,000 lb·in. For 900 lb at 26 inches, the moment is 23,400 lb·in. The total moment is 30,400 lb·in, and the total weight is 1,600 lb. Dividing gives 30,400 / 1,600 = 19 inches. So the center of gravity sits at 19 inches from the reference, between the two ballast placements and slightly toward the heavier 900 lb ballast at 26 inches.