Hello, I have very interesting physic problem. But i really have no idea how to solve it... Maybe somebody can give me some useful hints? Here we go: "Air drag (air resistance, drag) is a resisitvie force which is the result of a moving object colliding with air molecules. Dervie the drag formula for a thin disc of area A moving with velocity v throught the air. Treat the air as a dense crowd of tiny particles, of concentration n0 per m^3 and with each having a mass u. Treat the collision as elastic ones. You should obtain the expression of the form Fd = 0.5 C q v^2 A, where C is a dimensionless drag coefficient, and q is air density"