Now When galileo performed his experiment it was not in a vaccum here there was force retarding the motion (the viscous force) which depends on the velocity hence this leads to retardation which will be the function of distance as velocity increases with increase in distance.

you mean that velocity decreases with increasing distance due to the viscous force because of air??

i dont quite inderstand ur qn...galelio concluded the rate of change of velocity is constant for all objects what is meant by that is it is independent of mass  he never said anything about the rate of change of the same body with distance   that rate differs due to acce due to gravity but the change is same for all bodies regardless of mass...this is what he meant  if im correct u understood his statement wrongly...

no no this is not xactly a question, this line was written in ncert. nd thats why i asked it... look galileo was experimentin that tym and he found out that change in velocity with distance is not constant... it decreases with the increasing distance of falll.....so my question was how... nd its a free fall so mass does not come anywhere na?? its independent of the mass, xactly wat u said...

 When a body is in free fall, as galileo rightly pointed out the acceleration is the same (g). but i don't see anything responsible other than the viscous force of air for decreasing change in velocity with increasing distance! viscous force of air is extremely extremely small so i reckon it might be a misprint or maybe i have missed something :O

Viscous force of air is not that small. When objects fall the drag force due to air is proportional to velocity of object. So when an object falls there will be a reduction in acceleration but not velocity.

Velocity keeps on increasing till a stage where drag force becomes equal to the gravitational force on the fallin object. This velocity is termed as terminal velocity. Rain drops fall to earth in terminal velocity and without any acceleration.

Most of the falling solid objects even burn off/melt  before reaching earth due to air friction like meteors.

thnx guys 4 helpin... i finally understood!!!!