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It is all about the loss of energy during each stride - the tendons store some energy, but not a lot. A kangaroo and a greyhound, for example, have far more efficient elastic storage in their legs / tendons, allowing them to achieve (and maintain) greater speeds with less effort. Key phrase from the abstract in that reference: elastic storage of energy ...


2

I don't think it's clearly physics, but ... The same shape assumes your head or your hand or ... Circle (sphere) is the most efficient as regards the proportions of the "content" and the "skin". Any other shape requires more protective cover to hold the same amount of "content". And protecting the body from the outside world is the most important function ...


2

This phenomenon is probably related to the cold shock response, a set of physiological changes that come about in response to rapid temperature change, such as that experienced by a human whose face is immersed in a cold fluid. The response is accompanied by respiratory changes, including an initial gasp (see here). It is related to the dive reflex. This ...


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Let's assume the drag coefficient for the borrowers is the same as that for a human. The drag force depends on the velocity and the area, which will be 144 times smaller, if your assumption of " twelve times smaller in each dimension" is correct. \begin{align} F_D &= 0.5 \rho V^2 S C_D \\ &= 0.5 \rho C_D V^2 \frac{S_{\rm human}}{144} \\ \end{align} ...


1

Schrödinger's work is known for two distinct ideas relating to the nature of living systems. The first is what he called "order from disorder," meaning the way in which organisms can maintain a low entropy (or high free energy) state by increasing the entropy of their environment. (I.e. by eating low-entropy food and excreting high-entropy waste). Although ...


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Because work done to pull a pulley is less and the wind resistance is less while cycling than while walking because of the aerodynamic shape of the cycle. While cycling you are sitting and while walking you are standing which requires more energy. The friction between the tires and the ground is less than our legs and ground.


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This would be perhaps better off as a comment, but my reputation says I can't yet comment. All the other answers get the physics aspect right, but there is more to it from the biology point of view which might help the total average: you can rest on a bicycle more effectively. You can rest (or at least save some energy) going downhill (while actually ...


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faster long-distance runners hit ~20 km/h (marathon records) while fastest cyclists can do ~40 km/h So what causes the difference? different cardiac activity? different power output during these activities? more energy loss for running? friction? impact of the bike gearing? something else? That is the main negative factor, than ...


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If all you did was drink distilled water, it would not be terribly healthy for you. But most people eat as well - and that combination probably includes "healthy" minerals. Unless you binge-drink distilled water without any food, it's unlikely to cause serious health effects. Having said that - ions are pretty small - certainly smaller than 15 nm. But their ...



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