Originally posted by sir_chancealot
If a plane just "falls", the only thing that can happen is zero Gs. Everyone will become weightless. You won't be violently thrown to the ceiling
(gravity doesn't take "longer" to pull you down than the plane itself). However, if the pilot put the plane into a negative G dive (for whatever
reason) then people WOULD be thrown to the ceiling.
I think you are confused. You're confusing a Keplerian Trajectory with what a sudden, externally influenced, downward "push" in altitude. Put a
quarter inside of a box with the top open and violently push/pull it toward the ground, what do you notice? The box, of course, is accelerating
faster than gravity but the quarter is not. If the downward acceleration is great enough, and the box was closed, the quarter would be pressed
against the top of the box for the duration and then slammed to the bottom once acceleration ceased. However, if you just drop the box with the
quarter in it, that won't happen and both the box and the quarter will fall at the same time.
The plane is not "falling" when it hits turbulence, rather, it is being pushed down (or up) by a more dense or faster moving pocket of air, so it is
experiencing that force plus gravity. Depending on how long this lasts, and how powerful the acceleration, the forces acting would have you hit the
ceiling - much like the quarter in a box - and continually press you against it until the downward acceleration stopped - after which, you would
likely be slammed against your seat or other people.
If the passengers in the plane, or anything else, is not secured somehow to the body of the plane, when it goes down, they go up, if it goes left,
they go right, etc...