> Hi!
> I don't doubt that the gravitational acceleration of 9.81 m/s2 is
> right but somehow it often looks too low for me.
varies from place to place, but that is a good estimate. ;)
I have discussed the same concern with game producers.
The problem as I see it is that few people have watched
cars hit abrupt steep ramps at 250 kph and leave
the ground. The effect of a 5 degree flight path angle
at 250 kph are, well, roughly 2.5 times as great ;)
as at a more normal speed of 100 kph.
Most games also have visual fields of view that
are compressed. If you aren't used to compensating for the
effects you can't really evaluate the motion properly.
Even if you drop the car from rest they will note the
apparent slow motion at the start of the acceleration
and ignore how fast the car has gotten just moments
later as it hits (as it does in real life.)
Another problem is that most people are bad at telling
time in small increments. I was once told that a 4 sec
drop test took 7 sec, with back of the envelope
calculations to show that our gravity must be very wrong.
The actual problem in this case was in the calibration
of the one-Mississippi two-Mississippi three-Mississippi
experimental equipment ;).
Depends on the upward component of the velocity as they leave the
ground. (How steep they are flying and how fast they are going.)
In games, an artist can easily put in several degrees of ramp
without noticing it. The "Looks flat to me" problem ;)
Also, see comments above about off the cuff time measurements :)
--
Matthew V. Jessick Motorsims
Vehicle Dynamics Engineer (972)910-8866 Ext.125, Fax: (972)910-8216