Im trying to win an argument. Please help?

Question

If a plane was shot down from 35,000 feet, how long will it take to hit the ground?

Answer 1

The _soonest_ it could hit the ground is about 47 seconds. That assumes that there is no air resistance to slow its descent. In reality, the air resistance will slow it down, but it's hard to say by how much. So the best I can tell you is that it would take "at least" 47 seconds. This is based on the gravity acceleration formula:

t = sqrt(2*h/g)

Answer 2

Are the wings still attached? If so, it will still be generating some lift, thus it won't just drop. Also, you can't even just apply good old acceleration due to gravity because the viscosity of the air will slow the fall. Closest you could probably do is gravitational settling of a solid particle in a fluid (the fluid being air in this case), however it would be hard to approximate an aircraft for the settling without making wild assumptions or otherwise making a hugely over-complex calculation. You could perhaps model a cylinder in gravitational settling... a cylinder isn't too far off from an airplane (if you assume the wings have been severed).

Answer 3

What exactly does "shot down" mean? if only the pilot was incapacitated, and the plane in in a power dive, it could hit the ground even sooner than gravity alone would bring it down.
In short, the question as asked has no specific answer, we can't even give a really definite minimum number.