Three boxes move through the air. Rank in order, from largest to smallest, the m

Question

Three boxes move through the air. Rank in order, from largest to smallest, the magnitude of the three drag forces D(a), D(b) and D(c) acting on the boxes. Some may be equal.

Box A - velocity = 6m/s & dimentions are 20cm X 30cm

Box B - velocity = 6m/s & dimentions are 20cm X 20cm

Box C - velocity = 4m/s & dimentions are 30cm X 30cm

I was going off the equation:

Drag = 1/2 (density)(velocity)^2(Cd)(A)

Because they are in the same refrence area and are similar boxes, I thought you could disregard Cd and A because they would be the same in all three drag magnitues. I then wanted to plug in the densities, but you can't really do that because you are missing information. I decided that I am going about this the wrong way. How do you do this problem?

Explanation / Answer

I figured it out myself after a few hours: the order is a is the largest and b and c are tied. I was correct in assuming that you could neglect the Cd as well as the A and go off those values. I looked up this really complicated way to relate area to density and plugged those values in. It was correct.

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