In fact it was a bad example, but the only one i could come up with at noon.

Well, just remember the hammer and the feather experience done in space. :D

any object will given a long enough fall, reach their terminal velocity by 9,8 m/s/s by http://upload.wikimedia.org/math/6/e...b3a7f16172.png

Vt is the terminal velocity,
m is the mass of the falling object,
g is gravitational acceleration,
Cd is the drag coefficient,
ρ is the density of the fluid the object is falling through, and
A is the object's cross-sectional area.

On the contrary. As stated earlier in this thread, the two masses (say 2kg and 4kg) would experience the same force of gravity and thus, all other things being equal, fall towards the ground from any given altitude, at the same rate. On the other hand, if we actually take into account the gravitational forces applied by the masses on Earth, there is a very small, for all intents and purposes, unmeasureably miniscule difference in the rates at which they would fall. For two VERY massive objects, the rate would be significantly different than for one very massive object and something lighter, like a building, or a bowling ball, or a feather (all of which would be significantly lighter than the "very massive" object.

^ Thank you for further explaining it. 8)

^^ No prob...at least I get to use the Physics degree somewhere! :-D

ok leaving drag out of it, and making the gravitational pulling question a bit more uhmm clear...

the effect we are looking for is more suited for an example in space... imagine placing a planet next to the sun, and then imagine placing another star next to the sun. What we are trying to determine is whether or not the rate of which the gap between the objects close is the same.

i'm suddenly starting to have my doubts

ok...put the Earth next to the Sun...the distance between the two would decrease at rate A, given that the two started from fixed positions and moved in a straight line towards each other (yes, both would be moving as, they would both exert some gravitational pull on each other).

Now put a star the same mass as the Sun next to the Sun, under the same conditions as the Earth-Sun system, the distance between the two would decrease at rate B, which would be GREATER than rate A, as the gravitational forces at work would be significantly greater than in the Earth-Sun system.

Now, the only reason that there is a MEASUREABLE difference between the two is because the Sun (and the star in question) is significantly more massive than the Earth.