So, I've been having a bit of an argument with a guy about falling, identical items, with varying masses. 1. The problem statement, all variables and given/known data For the sake of the argument, we've been using the example of two identical jugs, one filled with water, and the other without. They are dropped at exactly the same time. I believe the one filled with water will hit the ground first, due to air resistance. He believes they will hit at the same time. I agree that they will, in a vacuum. 2. Relevant equations Force of Air Resistance = Constant Fg = m * g 3. The attempt at a solution http://www.physicsclassroom.com/class/newtlaws/u2l3e.cfm In situations in which there is air resistance, more massive objects fall faster than less massive objects. But why? To answer the why question, it is necessary to consider the free-body diagrams for objects of different mass. Consider the falling motion of two skydivers: one with a mass of 100 kg (skydiver plus parachute) and the other with a mass of 150 kg (skydiver plus parachute). The free-body diagrams are shown below for the instant in time in which they have reached terminal velocity. I'm not entirely sure why we're still having this argument, but he's very insistent, so I'd like a final answer from someone who knows this firsthand.