I was in my physics of the human body class and we got on the topic of pistons. It was given to me that the dampening force pertaining to such a piston filled with a gas is proportional to the square of the velocity of the piston; however, for fluids it was given as simply proportional to the velocity. So my question is why is this true? I suspect the fact that liquids have intermolecular forces present and ideal gases don't (in real gases these forces are very weak) has something to do with this but I'm not sure how. Thanks in advance for your input guys and girls! To clarify what I'm asking about: I'm asking why the dampening force associated with a gas filled piston is proportional to v^2 rather than v.