Ok, classic old question. Two tennis balls dropped from a very high height. One normal, one filled with lead, for example. So what will hit first? I am certain that they will hit together (theoretically) by looking at the equation v = u + at so no mention of weight or mass. However equally there is no mention of air resistance. Now I know these are the same shape however when arguing my point someone said that the heavier ball would cut through the drag better. I can't really see this being true however I would like this confirmed.... So, basically my question is, in the real world what would happen?