Hi Wu,
Nice question. The answer is yes. If you accelerate an elevator
upwards at the acceleration of gravity (9.8 m/sec^2), then the strength
of "gravity" inside the room will be double earth's gravity. And if you
accelerate it at 19.6 m/s^2, you get three times the gravity in that
room.
This isn't quite as trivial as it may sound. Einstein, while
working on the General Theory of Relativity, hypothesized that
acceleration due to gravity is indistinguishable in every way from
acceleration due to anything else (as long as the gravitational field
does not change over the volume of the elevator -- otherwise you get
"tidal" effects). If the elevator is falling freely, then it will be
impossible, from inside the elevator, to tell that one is not in space
far away from any gravitating planets or stars. It is the cable on the
elevator and our feet on the ground accelerating us away from our
natural free-falling trajectories which are determined by the geometry
of space and time.
A more practical piece of equipment for testing the effects of
large accelerations is a centrifuge. NASA uses (or used) them to train
astronauts. These are distinguishable from gravity because they turn
around in circles, and lots of experiments (notably, with gyroscopes)
can detect rotational motion and differentiate between that and uniform
acceleration.
Tom J.
(published on 10/22/2007)
