KIM. Fri fall fart är när byggnaden faller och inget underifrån tar emot alltså det bara flyger igenom luften rakt ner som om du släppte en en krona från taket.
From experimentation, it has been discovered that, near the surface of the Earth, Earth's gravity will produce a downward acceleration of 32 feet per second per second.
What that means is that an object, after falling one second, will be falling at 32 ft/sec.
After the 2nd second, it will be falling at 64 ft/sec.
After the 3rd second, it will be falling at 96 ft/sec.
And so on.
Further, since gravity's acceleration is constant, and it's falling at 32 ft/sec after one second has elapsed, we know that it has averaged 16 ft/sec for the entire distance, which, after one second, is 16 feet.
As you might imagine, after quite a few such thought experiments, some simple free-fall equations have been derived which can be used to harness this knowledge via numbers and arithmetic:
Velocity = Gravity x Time
and
Distance = 1/2 x Gravity x Time(squared)
So if we want to know how far the object has free-fallen after 3 seconds:
Distance = 1/2 x 32 x 9 = 144 feet
So after 3 seconds, in Earth's gravity, an object will have fallen 144 feet and will be falling at 96 ft/sec.
Läs mer här
http://911blimp.net/prf_FreeFallPhysics.shtml