oh i'm going to mess things up. Any thing of similar shape will drop the same distance in a given amount of time, a feather and a rock don't apply as the feather has a wide enough surface (so would say a piece of paper) to trap air under so it floats down, if you sqeezed the feather into a ball then it would drop the same distance in a given amount of time. If you dropped a rock straight down, and fired a 300 win mag with the barrel level over a level area both would hit the ground at the same time. The test I did so many years ago when they taught us this silly idea in school was to drop a 1 lb and a 10 lb rock off a 30' silo. It still does't seem right but it is