Hi all. This is my first question on these forums. I am given a task to test out whether or not FD=1/2 CDAρv2 is a good model to test drag force. Where CD is described by Reynold's Number. We have a balloon a small ball and a myriad of basic physics lab equipment. What is a experiment I could do that would test this model and its reliability? I'm thinking of dropping the ball into the graduated cylinder and timing it hitting the bottom to get its velocity. I have the density of water, as well as the cross sectional area (it's half the area of the ball, right?). When it comes to CD, the drag coefficient, I'm simply confused about determining linear size of the object to obtain Reynold's number. After I figure that out though, I think I'll be good. Is this a good idea? Will it accurately test the model? My only confusion is that if I'm testing to see if it's reliable, don't I need something to compare? I have nothing else. Thanks!