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Given that the total mass of an aeroplane is 112 000 kg with a centre of gravity position at 22.62 m aft of the datum. The centre of gravity limits are between 18 m and 22 m.

How much mass must be removed from the rear hold (30 m aft of the datum) to move the centre of gravity to the middle of the limits?

  • A

    16 529 kg

  • B

    8 680 kg

  • C

    43 120 kg

  • D

    29 344 kg

The Center of Gravity (CG) is where the entire mass is evenly distributed. Remember the formula for CG calculation:

  • CG = Total Moment ÷ Total Mass
    Where Total Moment = Total Mass x CG.

To determine the mass, we'll use a simple equation. By calculating the total moment in the current configuration and subtracting the moment of the load removal, we can ascertain the new total moment. Given the provided data - old and new CG, station of load removal, and total mass, we may find the mass "m" of the load removal:

New Total Moment = Old Total Moment - Load Removal
(112 000 - m) × 20 = 112 000 × 22.62 - m × 30
112 000 × 20 - m × 20 = 112 000 × 22.62 - m × 30
2 240 000 - m × 20 = 2 533 440 - m × 30
-m × 20 = 293 440 - m × 30
m × 10 = 293 440
m = 29 344 kg


Alternatively, for a more straightforward approach, you may use the following formula:
Change in Mass / Old Total Mass = Change in CG / Distance from mass to new CG

Change in Mass = (Change in CG / distance from mass to new CG) x Old total mass
Change in Mass = (2.62 / 10) x 112 000
Change in Mass = 29 344 kg

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