In the data, the numbers +352 and +380 appear next to weights. What do these numbers represent?

• A. Distances from the datum line (inches)
• B. Weights in pounds
• C. Moments in inch-pounds
• D. Times in seconds

Answer: (A)

These numbers are the arm values—the distance from the datum line to where that weight is located, measured in inches. They show how far the weight sits from the reference point and, with the sign, indicate direction relative to the datum. This arm is what you multiply by the weight to get the moment around the datum, which is how CG calculations are built. The numbers aren’t the actual weights (those would be in pounds), they aren’t moments (moments are weight times arm and would be larger values in inch-pounds), and they aren’t times. For example, a 200-pound item with an arm of +352 inches would have a moment of 200 × 352 = 70,400 inch-pounds.