I think you are confused about the word 'simulation'. A game like
tetris, where the blocks fall down the screen, is not in any way a
simulation, but it does have some idea of gravity. The blocks fall at
a constant speed, so there is no resultant force acting on the block,
so either there is no gravitational force acting on the block, or the
block has reached terminal velocity, where the air resistance stops it
from accelerating towards the ground. We can discount this second
theory because if you had a block which was straight (ie four squares
in a row), it would slow down when you rotated it from vertical to
horizontal, as there would be more air resistance. So tetris does not
model air resistance. Therefore, it does not 'simulate' gravity. It
does however have a 'notion' of gravity, as the blocks move down the
screen (pixel by pixel), instead of up or diagonally or some other
direction. That is obvious, but I spelled it out for you.
A 'simulation' would actually model the equations of motion which can
be used to calculate the gravitational force on an object. Usually,
-9.81m/(s^2) will suffice as an approximation of gravitational
acceleration at the Earth's surface, and when that value of
acceleration is applied to an object, it falls in a realistic manner.
Technically, a true 'simulation' would calculate the equation G = (m1
* m2)/(r^2) for two masses, at a distance r from each other. This is a
more complete 'simulation' of the effects of gravity, and works in
cases where the first one does not (ie not at the surface of planet
Earth, or where another large mass is concerned). Usually for a game,
this is not necessary, as it approximates to -9.81m/(s^2) anyway.
So, in conclusion, just because something moves downwards through the
air, or moves forwards when you push a button marked 'accelerator',
doesn't mean it is a 'simulation'. Even the best racing 'sims' we play
today, 'simulate' an extremely small amount of what is actually
happening, for example, most racing 'sims' model a car engine as two
torque curves, one at 100% throttle, and one at 0%. They then linearly
interpolate between these two values at a given RPM to get a resultant
torque. Is that simulating an engine? In absolutely no way whatsoever,
but it approximates the output you would get in real life. Does
Pacejka 'simulate' how tyres work? No, it is a mathematical function
which generates a graph, and this graph loosely fits over someone's
experimental data from a real tyre.
You are thinking that the most basic game is a 'simulation' in the
most basic sense, while something like NR2002 is a full 'simulator'.
Well, NR2002 is a 'simulation' in the most basic sense, and we have
yet to see where more computing power and more understanding of the
nature of physics will lead us in decades to come.
Ithankyou.
