複雜系統之簡介(梁鈞泰) - 中研院物理研究所- Academia Sinica
複雜系統之簡介(梁鈞泰) - 中研院物理研究所- Academia Sinica
複雜系統之簡介(梁鈞泰) - 中研院物理研究所- Academia Sinica
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2. Mechanism of locomotion<br />
To move, one must push on something backward, something that carries<br />
the momentum. It's the ground (earth) that we push when we walk, and<br />
vortices in water when we swim. How about for water striders?<br />
Long believed to be surface waves (capillary waves).<br />
But surface wave speed = (4 g σ/ρ) ¼ = 23 cm/s for water.<br />
A strider must beat its legs faster than this speed.<br />
No problem for adults, but measurements show that infant striders<br />
can’t beat that fast.<br />
Denny's paradox.