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29

Assume also that I have access to an immense amount of parallel computing processing power (I do). Unless you are an important person in the Chinese computational science world (using Tianhe-2), or you have access to secret government computers us mere mortals don't know exist (so they don't appear in rankings of the best supercomputers in the world), I ...


26

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 ...


6

There are two primary factors that allow the cochlea to isolate frequencies. These are generally referred to as passive and active properties: tl;dr version: The passive properties are due to the mechnical properties of one of the membranes in the cochlea, the basilar membrane, primarily the width and stiffness at a given point. The active properties are ...


4

The cochlea has a complex physical structure, with multiple membranes and fluid-filled chambers. Therefore to explain the separation of frequencies along the basilar membrane of the cochlea is complex to. Sure, there are a lot of very general descriptions (even the answer of theblackcat) and a lot never go into the actual physics of the system. This ...


3

UPDATE - With a reference to: http://www.researchgate.net/publication/48323925_Applying_physics_makes_auditory_sense__a_new_paradigm_in_hearing OP, user263399, COMMENT: Can you explain the phase wave and its cause? On reading the linked paper I'm confused on how ther explanation involving the change in liquid volume velocity would create a ...


2

There is some interesting data on the subject. People looked at the relationship between the prevalence of radon in counties in the US with the mortality due to lung cancer, and found a surprising relationship. Instead of the "more radon kills more people" correlation that was expected, there was an initial "dip" in the curve - as though "a little bit of ...


2

I believe that as the body starts to decompose, the action of bacteria, particularly in the gut, produce gases, which are trapped. The gases expand the volume of the body, thereby reducing its density and hence leading to buoyancy, which causes the body to float. Interesting that a question which looks like physics has a biological answer.


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 ...


2

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

What affects would traveling at this speed have on the human body? The Earth revolves around the Sun at 18.5 miles per second and humans (as well as other living things) don't seem to notice. In addition, the Sun is travelling around the Milky Way at 143 miles per second. The astronauts and cosmonauts aboard the ISS are travelling at about 4.75 miles ...


1

Raphael, Active SONAR emits pressure waves that bounce off of things in the water; the timing of the pressure wave bounced back is used to measure distance and develop images of what is underwater. Given that the energy in the pressure wave dissipates at a rate defined by the inverse of the square of the distance traveled (1/r^2), it obviously takes a ...


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 ...


1

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.


1

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 ...


1

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 ...


1

The explanation that I heard was that the human body with air in the lungs is less dense than water but with water in lungs such as drowning is more dense than water and sinks. The underwater, presumably dead body, still has live gas producing bacteria in the intestines which start to digest undigested food and eventually the dead person's tissues. When ...


1

For our three compartment hearing sense, from a physics point of view, there is a basilar membrane stimulation, from base to apex, in its pathway in the cochlea, to a place on the basilar membrane. By periodic movement of perilymph, non viscous fluid, backwards and forewards, in the cochlear duct meet the conditions of a potential flow. The basilar ...


1

If two twins (or clocks) decide to go live in differently strong gravity wells, they will age at different rates. It isn't based on where you were born. In particular it is not just that different planets spin at different rates or orbit their stars at different rates. Clocks just tick slower in a deeper gravity well. Hearts beat slower. Synapses fire ...


1

The general answer is "yes". There is a current flow through the solution and if you put part of yourself into it then part of the current will flow through you. How much current is the real question, and that depends on a whole lot of variables such as voltage and current between the electrodes, their separation, where you place the biological component, ...


1

As a chemist turned engineer, I think I am well placed to answer this question. Does there exist a graphics engine that is as true to our reality as possible given our current understanding of physics? Given appropriate constraints and simplifications, it is possible to build a useful model from simple elements. Whether you consider this "true to ...


1

Oh, I love this subject. The term here is radiation hormesis, and it's basically off-limits for nuclear regulators (If it's true, it horribly complicates the risk analysis for the use of any radiation source). The classic study comes from Taiwan http://www.jpands.org/vol9no1/chen.pdf where a number of apartment buildings were built using rebar that had been ...


1

The potential difference between the two points on the wire is negligible at all times but initially there's a potential difference between the wire and the bird and there would be a (very short lived) transient current which is similar to electrostatic discharge you feel when you touch an object with electrostatic charge build-up.


1

Perhaps I could share some idea for further research. If we could make actual and correct pressure measurements in the cochlea to reveal wether the non-stationary Bernoulli effect is a good description of the actual physics-of-how-the-cochlea-isolates-frequencies-along-its-length? I would consider: I would propose to use a pitot tube, with sensor in the ...



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