If you move the entire payload from the rear seat (arm 84 in) to the front seat (arm 60 in) without changing total weight, what happens to CG?

• A. CG moves forward (toward the nose) because weight is shifted to a smaller arm.
• B. CG moves aft toward the tail
• C. CG remains the same
• D. CG becomes undefined

Answer: (A)

Center of gravity location is the total moment divided by total weight. If you move the same weight from a rear location at 84 inches to a front location at 60 inches, the total weight stays the same but the moment changes. Since the weight is moved from a larger arm to a smaller arm, the sum of weight times arm (the moment) decreases. With a smaller moment over the same total weight, the CG value moves toward the nose (forward).

In math terms, moving Δw from 84 in to 60 in changes the moment by ΔM = Δw(60 − 84) = −Δw(24). The total weight W is unchanged, so the new CG x̄ = M′/W is smaller than before, i.e., forward. This is why shifting payload to a smaller arm makes the CG move forward.

So the correct result is that the CG moves forward toward the nose.