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A comment on Show HN: Long Range E-Bike. Parent comment

Re:Show HN: Long Range E-Bike by sokoloff on Friday November 12, 2021 @10:27PM (#29207130)
> you really start to feel the air resistance and it becomes exponentially harder to go beyond 45kph

Nitpick: it becomes cubically harder. ;)

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Re:Show HN: Long Range E-Bike by antisthenes on Saturday November 13, 2021 @12:08AM (#29207566)
Nitpick to nitpick: cubically is a subset of exponentially.
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Re:Show HN: Long Range E-Bike by newaccount74 on Saturday November 13, 2021 @12:48AM (#29207748)
You are both wrong. Air resistance increases quadratically with speed, not cubically. And you mixed up polynomial with exponential.

Quadratic: x^2

Cubic: x^3

Polynomial (eg. 3rd degree): a + b x + c x^2 + d x^3

Exponential: e^x

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Re:Show HN: Long Range E-Bike by sokoloff on Saturday November 13, 2021 @03:44AM (#29208396)
Drag force rises quadratically with speed. Power is force dot velocity; in this case force and velocity are in the same direction, so dot product becomes simple mulitiplication making drag power (exertion, formally: work per unit time) cubic with speed.
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Re:Show HN: Long Range E-Bike by newaccount74 on Saturday November 13, 2021 @04:41AM (#29208648)
Oh, you are right! Sorry.
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