- #1
Physicsterian
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Homework Statement
- Question: Which cyclist (A, B or C) profits the most from cyclist slipstream (also called “aerodynamic drafting”)?
- Given: the direction of the wind, the positions of each cyclist; an illustration representing this
- NOTE that I am expected to solve this question conceptually, without using a pen, paper and/or calculator. From personal interest, however, I am also wondering if the problem could be solved concretely. However, the priority right now is, solving it conceptually.
Homework Equations
- Perhaps, the drag reduction due to slipstream could be estimated(/calculated) by using the drag equation, which is FD = ½ ρ * v^2 * Cd * A (with FD = Drag force, ρ = fluid density, v = Relative velocity between the fluid and the object, Cd = Drag coefficient and A = Transversal area or cross sectional area)
The Attempt at a Solution
According to the answer sheet, confusingly enough, the answer is cyclist B. What I can make up from the situation is that cyclist A catches up a significant amount of the oncoming wind force, which favors cyclist B in that he or she has to put in less effort against the wind force. The x as well as y component of the wind force are reduced, meaning that the "v^2" in "FD" and thus "FD" becomes smaller. So far, so clear. However, I do not get it why it is not cyclist C who profits the most of drag-reduction, as cyclist B catches up a great amount of the wind that passes by cyclist A, wherefore C should face the oncoming wind even less than B. Wondering what I am doing wrong. The only reason I can think of is the fact there are three arrows and that that might be explanatory for B profiting more from slipstream compared to C, but I fail to make a logical conclusion.
Might something not be clear enough, please let me know.
Thanks a lot in advance.
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