3 ms·
Very cool. It seems less paradoxical when you think in terms of energy instead of speed. In other words, thinking about it as (1) drawing energy from the wind
by techiferous 16y ago
Very cool.
It seems less paradoxical when you think in terms of energy instead of speed. In other words, thinking about it as (1) drawing energy from the wind and transforming this energy into forward physical motion instead of (2) the wind pushing something faster than itself.
- mechanical_fish 16y agoYes, this is why the concept of energy is given such a prominent position in physics. It is a great tool for predicting what might happen even when the detailed mechanism is unknown or seemingly impossible. I haven't yet taken the time to understand the details of these explanations, but when I heard about this cart I immediately thought "hmm, the wind is blowing, there's energy all around, so some tricky person can probably figure out how to make use of that energy; hence, it's plausible". Of course, the flip side of this principle is that physicists can be driven to spend years and years and years trying to extract energy that is obviously there, but that has no known mechanism for getting it out. The classic example is nuclear fusion. Everybody knows it's energetically favorable; nobody knows how to get over or under the activation barrier in any useful way, other than "build something the size of a star".
- jacquesm 16y ago> build something the size of a star It will even contract all by itself and ignite.