Timeline for Linear relationship between air resistance and power consumption?
Current License: CC BY-SA 4.0
9 events
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| May 8, 2020 at 13:47 | comment | added | mmesser314 | In part c, the idea that doubling the velocity doubles the air resistance is wrong. The link shows why air resistance goes up 8 times. As I said above, to does all the power used to overcome air resistance: that is a better approximation at high speeds than low speeds. | |
| May 8, 2020 at 5:35 | comment | added | Max | I mean in the context of the question posed. In part (c), doubling the velocity doubles the air resistance, which doubles the power consumption (compared to the 30 m/s scenario where the velocity increases without doubling the air resistance)—a linear relationship. From your comment, I deduce that the answer to "Is the problem implying that all of the power delivered to the wheels is used to overcome air resistance?" is yes. Is that right? | |
| S May 8, 2020 at 3:37 | history | edited | Max | CC BY-SA 4.0 |
improved format
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| S May 8, 2020 at 3:37 | history | suggested | Harish Chandra Rajpoot | CC BY-SA 4.0 |
improved format
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| May 8, 2020 at 3:32 | review | Suggested edits | |||
| S May 8, 2020 at 3:37 | |||||
| May 8, 2020 at 3:22 | comment | added | mmesser314 | The relationship is not linear. It is cubic. Yes and no. At low speed it is a better approximation that all of the power overcomes engine friction. The faster you go, the better the approximation that is all goes to air resistance. Fluid dynamics is very complex. It full of rules of thumb that simplify life, even if they are not perfect. | |
| May 8, 2020 at 3:16 | comment | added | Max | Thanks for the link. So—yes? | |
| May 8, 2020 at 3:14 | comment | added | mmesser314 | This post is about a fan blowing air, but it applies to a car driving through air too. physics.stackexchange.com/q/536074/37364. Internal friction, particularly in the engine dominates at low speed. I have heard that around 35 mph, air becomes more important. Air dominates at high speed.But I don't have a model of engine friction. | |
| May 8, 2020 at 2:53 | history | asked | Max | CC BY-SA 4.0 |