All Hokie, All the Time. Period.

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Joined: 01/17/2008 Posts: 6023
Likes: 1470

It wouldn't shock me because I don't think it's violating the law of

conservation of energy. More specifically, that a sail powered vehicle can't move faster than the wind pushing it is not because of limited energy in the wind. There's more energy there, it's just the manner it's being harnessed doesn't allow harnessing more energy. I.e. sails are not perfectly efficient. Similarly, it's why if you look at the energy contained in the gasoline you've burned in your car and the kinetic energy present, the latter is less. You don't capture all of the heat and you don't capture all of the wind's kinetic energy. Perhaps, the simplest counter-example is that the wind is still moving, therefore there is more kinetic energy present.

A more complicated counterexample, consider two ships of different masses. Next, consider that there exist sail sizes (i.e. more than enough) where both boats have the same max speed. So what that tells us is that the same surface area of sail and cross section of wind can deliver two different amounts of energy as the boat of greater mass has more energy. The total energy is the same, the different in kinetic energy is made up for by energy remaining in the air particles.

Another counterexample is to imagine a vehicle with a very long cord and a wind turbine. We could make that vehicle go a ton faster than the wind.

Okay, I've convinced myself, this working would not break the law of conservation of energy.

(In response to this post by EDGEMAN)

Posted: 06/10/2021 at 8:52PM


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