Re: [Phys-L] Impossible vehicles.

[bnorwood111@gmail.com]

(In the one-dimensional case) the sailboat’s speed is said to max out at wind speed, but actually it must be less than wind speed, due to the water drag on the boat.

Bill Norwood
U of MD at College Park

Sent from my iPhone

> On Jun 2, 2021, at 2:31 PM, Brian Whatcott <betwys1@sbcglobal.net> wrote:
>
> Here's the directly upwind version of a similar vehiclehttps://www.wired.com/2012/07/wind-powered-car-upwind/?redirectURL=https%3A%2F%2Fwww.wired.com%2F2012%2F07%2Fwind-powered-car-upwind%2F
>
>    On Wednesday, June 2, 2021, 01:09:42 PM CDT, Brian Whatcott <betwys1@sbcglobal.net> wrote:  
>
> I know of two vehicles that give rise to invective from physics professors: The sand-yacht that rolls directly down wind at twice the speed of the wind
> https://www.youtube.com/watch?v=jyQwgBAaBag
>
>
>
>
> Couldn't find a video of a toy boat with a big air propeller driving a small water prop directly upwind.But they exist!
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