1. The problem statement, all variables and given/known data Finding yourself in a nearly empty airplane, you take a seat other than your allotted seat. Soon, an air hostess comes up to you and requests you to occupy a different seat. What may be the reason? A) The plane momentum can change if the passengers change their position that affects the safety of the flight. B) Certain seating positions, when occupied in a nearly empty plane, would raise the center of gravity of the plane. C) Depending on the places occupied, inertia of the plane may decrease that allows the engine to provide less thrust and expend less fuel. D) Changing seats may keep the position of the center of mass of the plane unchanged. 2. Relevant equations Momentum Center of gravity 3. The attempt at a solution B or D? But I m not sure whether "raise center of gravity" would affect anything of the flight... As the weight is still remain the same...(vertical?) Thanks.